Application of Electrospun Nanofiber Membranes in Outdoor Sportswear: From Preparation Technologies to Multifunctional Integration

Abstract

Outdoor sportswear increasingly demands multifunctional performance, including waterproofness, breathability, and intelligent thermal regulation. Nanofiber membranes, especially those prepared via electrospinning, offer a promising platform due to their tunable pore structures, high specific surface area, and ease of functionalization. This review outlines progress from fabrication to multifunctional integration, highlighting key quantitative advances: electrospun membranes achieve water vapor transmission rates >10,000 g·m⁻²·day⁻¹ with hydrostatic pressure resistance of 80–150 kPa, and thermal conductivity as low as 0.033–0.040 W·m⁻¹·K⁻¹. We analyze how structural designs enable tailored functionalities for diverse outdoor scenarios. The review’s key contributions include establishing a clear “process-structure-function” framework, critically comparing nanofiber membranes with conventional materials, and identifying industrialization challenges—scalability, durability, cost—while pointing toward smart, sustainable, and customizable future directions.

1. Introduction

In recent years, with the rise of global health awareness and the increasing popularity of outdoor lifestyles, the outdoor sportswear market has continued to grow. Consumer demands for clothing performance have shifted beyond basic protection toward intelligence, comfort, and personalization [1,2]. This has driven continuous iteration in textile technology, with the core challenge focusing on how to synergistically optimize multiple performance aspects in extreme environments, such as balancing waterproofing and moisture permeability, warmth and heat dissipation, and protection and lightweight design. Currently, mainstream outdoor clothing primarily relies on multi-layer composite fabrics and microporous membrane technologies [3,4]. Although these traditional solutions are quite mature, their performance improvements are approaching physical limits, and they lack flexibility in multifunctional integration. Additionally, the production processes or disposal of some traditional materials face challenges related to environmental sustainability, which constitute key bottlenecks for the further development of current outdoor clothing technologies [5]. It is worth noting that conventional coating techniques (e.g., polyurethane wet coating, silicone coating) have been widely adopted for imparting waterproofness and wind resistance to textiles due to their mature industrial processes and cost-effectiveness. However, such coatings often form dense, continuous layers that inherently compromise breathability, limit multi-functional integration, and may involve solvents with environmental concerns. Against this backdrop, nanofiber membrane technology, particularly electrospinning, offers a new pathway to address these contradictions due to its unique structural designability. By precisely controlling fiber diameter, pore structure, and surface properties, nanofiber membranes can achieve performance combinations in a single-layer structure that traditionally require multi-layer fabrics, and even introduce active response and intelligent sensing functions that are difficult to achieve with conventional materials [6,7]. Their high specific surface area and ease of functional modification make them an excellent platform for integrating functional units such as phase change materials, conductive nanoparticles, and antibacterial agents, thereby meeting the urgent demand for adaptive, multifunctional, and integrated clothing in outdoor sports. Over the past five years, research on nanofiber membranes in areas such as waterproofing and moisture permeability, thermal and moisture management, and intelligent sensing has experienced explosive growth, with various new structures and composite material systems continuously emerging [8,9,10]. However, research achievements in this field remain relatively scattered, lacking systematic organization from basic preparation to scenario-specific applications. In particular, the correlation analysis between performance requirements for different outdoor sports categories and material design strategies is still insufficient. Therefore, this article, guided by the framework of structural design—functional realization—scenario adaptation, integrates the latest advancements in this field, clarifies the technological development trajectory, identifies current industrialization challenges, and proposes future directions for intelligence, personalization, and sustainable development, aiming to provide comprehensive reference and inspiration for researchers and industry practitioners in related fields.

2. Preparation Technologies, Structural Regulation, and Performance Relationships of Nanofiber Membranes

2.1. Electrospinning Technology

In recent years, with the rapid development of nanotechnology, electrospinning technology has become a research hotspot for preparing nanofibers due to its advantages such as simple equipment, convenient operation, low cost, good process controllability, and wide applicability [11]. Electrospinning technology can produce fibers with diameters ranging from tens of nanometers to several micrometers. These fibers possess extremely high specific surface area, high porosity, and a three-dimensional network structure, which can mimic the structural characteristics of natural extracellular matrices, providing an ideal platform for various applications [12]. After decades of development, electrospinning technology has evolved from single-needle spinning to various forms such as multi-needle, needleless, coaxial, and bubble electrospinning, significantly improving the production efficiency and structural diversity of nanofibers. Particularly in recent years, with a deeper understanding of the electrospinning mechanism and optimization of process parameters, this technology has gradually progressed from laboratory research to industrial production, demonstrating broad application prospects in multiple fields [13].

Electrospinning technology is an efficient method for preparing polymer nanofibers that utilizes high-voltage electrostatic field force as the driving force. A schematic diagram of a typical electrospinning setup is shown in Figure 1, which consists of four core components: a high-voltage power supply, a solution storage device, a jetting device, and a collection device [14]. The equipment for preparing nanofiber films using electrospinning technology in industry is shown in Figure 2. The fundamental principle involves using the high-voltage electrostatic field force to overcome the surface tension of the polymer solution or melt, enabling the stretching and thinning of the liquid jet, which ultimately solidifies into nanoscale fibers [15]. This process can be divided into three key stages: Taylor cone formation, jet instability, and fiber collection and solidification.

During the electrospinning process, when a high-voltage electrostatic field of thousands to tens of thousands of volts is applied between the metal nozzle (capillary) and the collection device, the polymer droplet at the nozzle tip is subjected to various forces. Surface tension maintains its spherical shape, while the electrostatic field force stretches it toward the collection device. As the electric field strength increases and overcomes the surface tension of the droplet, the droplet gradually transforms from spherical to conical, forming what is known as a “Taylor cone”. At the apex of the Taylor cone, where the electric field is most concentrated, a fine jet with a microscopic diameter is ejected, marking the beginning of the electrospinning process [16]. Once the electric field strength reaches a critical value, the electrostatic force overcomes the liquid’s surface tension, and a jet is ejected from the Taylor cone. As this jet travels toward the collection device, it undergoes high-frequency bending, oscillation, and irregular spiral motions under the influence of the high-voltage electric field, a phenomenon referred to as “jet instability”. This instability causes the jet to be stretched by tens of millions of times within milliseconds, rapidly reducing its diameter from the micrometer scale to the nanometer scale, while the solvent evaporates quickly. During the jet’s movement, the solvent continuously evaporates, the polymer concentration gradually increases, and the viscosity rises rapidly, ultimately leading to the solidification of the jet into solid nanofibers [18]. These fibers deposit randomly on the collection device, forming a nonwoven nanofiber membrane with high specific surface area and high porosity [19]. In the electrospinning process, key controllable parameters include the applied voltage, the distance between the nozzle and the collector, and the solution flow rate, which collectively regulate jet stability and the final morphology of the fibers. Typical optimization ranges for these parameters are as follows: the applied voltage is usually 5–30 kV, depending on the polymer-solvent system; the working distance between the nozzle and the collector is generally set between 5 and 20 cm; and the solution flow rate is typically adjusted within 0.1–2.0 mL/h. A schematic diagram of the nanofiber membrane fabrication process and the outdoor sportswear manufacturing process is shown in Figure 3 [20]. The final morphology of the fibers is influenced by various factors, including the type of polymer, solution concentration, electric field strength, collection distance, and environmental conditions.

2.2. Factors Influencing the Preparation of Nanofiber Membranes via Electrospinning Technology

Similar to many other processes, the electrospinning process is governed by operational parameters and the material properties of the substances being processed. The progression of the process and the characteristics of the product are controlled by these fundamental parameters. The structural properties of nanofiber membranes prepared by electrospinning are synergistically influenced by various factors, which can be systematically categorized into three types: solution properties, process parameters, and environmental conditions. The effects of these three types of electrospinning process parameters on fiber morphology are summarized in

Table 1. Influence of Electrospinning Process Parameters on Fiber Morphology.

Parameter Category	Specific Parameters	Effect on Fiber Morphology	Optimization Direction
Solution Properties	Concentration/Viscosity	Too low (8 wt%) tends to form beads, while too high (20 wt%) increases the diameter and may even clog the nozzle; viscosity is often positively correlated with fiber diameter.	Adjust to 2–2.5 times the critical concentration range, with the optimal spinning concentration being approximately 4–5 wt%.
	Elasticity/Relaxation Characteristics	Affects the stability and stretching behavior of the jet. High elasticity suppresses the bending instability of the jet, facilitating the formation of straighter and more uniform fibers; excessively low elasticity may lead to jet breakage or the formation of irregular fibers.	Select polymers with appropriate molecular weight/structure or add plasticizers for adjustment.
	Electrical conductivity	Increased electrical conductivity leads to reduced fiber diameter	Add an appropriate amount of salt or ionic liquid
	Surface Tension	Reducing surface tension helps initiate jetting	Adding an appropriate amount of surfactant
Process Parameters	Voltage	As voltage increases, the diameter first decreases and then increases, with the distribution broadening	Identify the optimal voltage value, typically 1.2–2 times the critical voltage. For many systems, optimize within the range of 10–20 kV.
	Receiving distance	Distance affects stretching and volatilization degree	Adjust according to solvent volatilization rate, commonly within the range of 10–20 cm. For low-volatility solvents, a longer distance is required (~20 cm); for high-volatility solvents, the distance can be shorter (~12 cm).
	Solution flow rate	Flow rate increases, diameter increases	Under the condition of ensuring a continuous jet, the flow rate is typically reduced to 0.1–2.0 mL/h.
Environmental conditions	Temperature	Affect solvent evaporation rate	Adjust according to the solvent boiling point (Tb), usually controlled within the range of Tb ± 10 °C.
	Humidity	Excessive levels leading to fiber moisture absorption or formation of porous structures	Control humidity based on material hydrophilicity/hydrophobicity: hydrophobic polymers can be electrospun at higher RH (40%–60%) to induce porous structures; hydrophilic polymers require low RH (<30%) to prevent moisture absorption and adhesion.
	Airflow velocity	Affecting volatilization kinetics	Maintain stable low-speed airflow (<0.5 m/s)

. These parameters are interrelated and collectively determine the morphology and performance of the final fiber product [21].

2.2.1. Solution Properties

The intrinsic properties of the precursor polymer solution are fundamental factors determining fiber morphology, and precise control of the solution’s parameters is the basis for preparing fibers with specific diameters and defect-free morphologies. The molecular weight, molecular weight distribution, and molecular structure of the polymer directly affect the spinnability of the solution. Polymers with higher molecular weights favor the formation of continuous, bead-free fibers due to enhanced chain entanglement. Solution concentration is closely related to viscosity; too low a concentration tends to form beads or broken chains, while too high a concentration leads to increased fiber diameter or even difficulty in jetting [22]. Solution concentration and viscosity are key factors in controlling fiber diameter and morphology. Under low-concentration conditions, insufficient molecular chain entanglement causes electrohydrodynamic instability, resulting in bead-on-string structures or even discrete droplets on the collector screen. As the polymer concentration increases, bead structures gradually decrease. When the concentration reaches 2–2.5 times the entanglement concentration, uniform-diameter, bead-free fibers can be obtained. However, excessively high viscosity hinders Taylor cone formation and restricts the electrostatic stretching and thinning of the jet, leading to increased fiber diameter or even clogging of the spinneret orifice.

Solution conductivity significantly influences jet stretching and fiber refinement. Higher conductivity enhances the jet’s charge-carrying capacity, thereby increasing the electrostatic stress experienced under a given electric field. This enhanced stretching force promotes jet thinning, enabling the production of fibers with smaller diameters and superior uniformity. Solution conductivity is typically adjusted by adding ionic salts or ionic liquids. However, excessively high conductivity may lead to excessive jet splitting and instability, potentially causing wider diameter distribution or the formation of porous fibers [23]. Furthermore, solution surface tension determines the critical voltage required for the electric field force to overcome droplet stability and form a Taylor cone. Lower surface tension facilitates the formation of a stable Taylor cone and jet ejection, thereby promoting the formation of finer fibers [24]. Surfactants are often added to fine-tune surface tension to improve jet stability and fiber morphology. The solvent evaporation rate governs the jet solidification kinetics. Highly volatile solvents promote rapid solidification, helping to maintain the morphology of stretched fibers, but may also lead to surface skinning and internal cavity defects. Conversely, low volatility solvents may result in incomplete solvent evaporation, causing fiber fusion upon deposition on the collector [25].

2.2.2. Process Parameters

External process parameters in electrospinning play a crucial regulatory role in fiber formation, with the applied voltage being the primary driving force. An appropriate voltage stabilizes the Taylor cone and ejects a uniform, bead-free jet; insufficient voltage prevents proper jet formation, while excessive voltage can trigger jet splitting, arcing, and other unstable phenomena, leading to a wider fiber diameter distribution or even thermal degradation. Simultaneously, the working distance between the spinneret and the collector affects the degree of jet stretching and solvent evaporation time. Too short a distance can easily lead to incomplete solvent evaporation and fiber adhesion, while too long a distance weakens the electric field strength, resulting in insufficient stretching and potential bead defects. The solution flow rate further regulates fiber morphology; a high flow rate generally increases fiber diameter and, due to insufficient drying, tends to form irregular morphologies; a low flow rate may disrupt jet continuity and affect production efficiency [26]. Beyond these basic parameters, the geometric configuration and material of the collector more directly determine the final fiber alignment and spatial structure. A static flat plate collector produces non-woven mats, whereas a rotating drum collector can induce fiber alignment along the rotation direction, enabling the fabrication of highly oriented fiber assemblies, such as successfully prepared continuous, aligned PEO nanofibers. Ultimately, the synergistic optimization of voltage, working distance, and flow rate, combined with the selected collection system, is essential for producing customized fiber morphologies, improving productivity, and achieving desired macroscopic material properties [27].

2.2.3. Environmental Conditions

In addition to the inherent properties of the solution and external process parameters, environmental factors such as temperature, humidity, and airflow also significantly influence the final morphology and microstructure of electrospun fibers. Temperature primarily affects solvent evaporation kinetics and solution viscosity. Increasing temperature accelerates solvent removal and promotes rapid fiber solidification, which can reduce fiber adhesion, but excessive heating may lead to premature drying and nozzle clogging. Conversely, low temperatures prolong the drying process, potentially causing fibers to flatten or adhere to each other upon deposition on the collector. Humidity has a more direct impact on fiber morphology, especially in systems involving volatile solvents. In high-humidity environments, water vapor condenses on the surface of newly formed jets through vapor-induced phase separation, resulting in porous surface structures. This phenomenon begins with isolated pores at moderate humidity levels and evolves into interconnected pore networks as humidity increases. This strategy has been effectively employed to significantly enhance the specific surface area of fibers, thereby improving their performance in filtration and catalysis applications [28]. Meanwhile, local airflow can disrupt the delicate trajectory of charged jets and alter solvent evaporation kinetics, leading to uneven fiber deposition. Therefore, precise and coordinated control of these environmental variables is crucial for the controllable preparation of nanofibers, ultimately achieving functional properties that are highly compatible with application scenarios. In industrial production, electrospinning is typically conducted in a constant temperature and humidity environment to ensure product consistency.

The electrospinning process enables the precise construction of nanofiber structures with customized properties through the coordinated regulation of solution properties, process parameters, and environmental conditions. By strategically adjusting parameters such as solution concentration, electric field strength, collector geometry, and environmental humidity, key structural characteristics including fiber diameter, internal porosity, surface morphology, and orientation can be independently or synergistically controlled.

2.3. Overview and Comparison of Other Fabrication Techniques

Although electrospinning technology dominates laboratory research, particularly excelling in precise structural control and multifunctional integration, from a comprehensive evaluation of industrialization potential, cost, and scalability, alternative technologies such as air-jet spinning may hold advantages in certain application scenarios. Based on recent assessments of industrialization prospects, Table 2 and Table 3 systematically compare and analyze the characteristics, advantages, disadvantages, and applicability of various nanofiber membrane preparation techniques. Each of these technologies has its own features and suitable application ranges, aiming to provide diverse options for the preparation of nanofibers and offer a multi-dimensional perspective for material selection in the field of outdoor apparel.

Air-jet spinning, as an emerging nanofiber fabrication technology, operates on the principle of utilizing the aerodynamic shear force and stretching action generated by high-speed airflow to directly break and refine polymer solutions or melts into nanofibers, followed by solvent evaporation and deposition onto a collector to form nonwoven fiber membranes [29]. The core advantage of this method lies in its complete avoidance of high-voltage electric fields, which not only reduces the requirements for polymer dielectric properties—enabling efficient processing of high-conductivity or high-viscosity solution systems—but also greatly simplifies equipment configuration and enhances process safety, demonstrating significant potential for large-scale industrial production. However, due to the complex fluid dynamics and difficult-to-control turbulent characteristics within the gas jet, the resulting fibers exhibit a broader diameter distribution, and achieving highly ordered fiber alignment remains a major challenge, which to some extent limits its application in advanced fields requiring highly ordered nanostructures.

Centrifugal spinning utilizes centrifugal force generated by high-speed rotation as the primary driving force for fiber formation. In this process, a polymer solution or melt is placed inside a rapidly rotating spinning head; when the centrifugal force overcomes the solution’s surface tension, jets are ejected from the nozzle tip and gradually stretched into fine fibers [30]. The advantages of this technique include high production efficiency and the absence of high-voltage electric fields or organic solvents, highlighting its great potential for industrial-scale production. The avoidance of high-voltage electric fields circumvents limitations related to the electrical properties of polymers, allowing for the processing of low-conductivity or non-polar materials. The elimination of organic solvents also brings significant improvements in environmental friendliness and safety. However, the produced fibers are typically deposited as isotropic nonwoven mats with random orientation, making it inherently challenging to achieve highly ordered fiber structures. Other limitations include the relatively complex mechanical structure of the equipment, significant operational noise and vibration, and current difficulties in fabricating complex multi-component fiber structures.

Self-assembly technology leverages weak intermolecular interactions to enable the spontaneous organization of molecules or particles into ordered nanofiber structures [31]. This method allows for precise control of fiber diameter at the molecular level, making it particularly suitable for producing ultrafine nanofibers. However, the self-assembly process is typically time-consuming and yields are extremely low, primarily limiting its use to laboratory research rather than industrial production. Template synthesis employs templates with nanochannels, where fibers are formed inside the channels via physical or chemical methods, followed by template removal to obtain nanofibers. This approach enables precise control over fiber diameter and length and is applicable to a variety of material systems. However, the main drawbacks of template synthesis include the complexity of the process, high template costs, and challenges in scaling up for large-scale applications.

Table 2. Comparison of advantages, disadvantages, and applicability of different nanofiber preparation techniques.

Fabrication Techniques	Main Advantages	Main Limitations	Applicable Materials	Commercial Feasibility
Electrospinning [32]	Simple equipment, uniform fibers, capable of producing complex structures	Requires high-voltage electric field, limited production capacity	Various polymer solutions/melts	Mainstream approach in laboratory research and high-end specialty products. Still faces efficiency and cost challenges in the textile and apparel sector [33].
Air-jet spinning [34]	No electric field required, high yield	Fiber diameter distribution wide	High viscosity solution	Possesses industrialization potential, suitable for fields requiring large-scale production with less stringent uniformity demands. More appropriate for use as a foundational functional layer in apparel [34].
Centrifugal spinning [35]	High safety, large output	Complex equipment, disordered fibers	Polymer solution/melt	Suitable for large-scale production of coarser nanofiber/microfiber nonwoven fabrics; less competitive in the high-end membrane segment of outdoor apparel [36].
Self-assembly [37]	Precise diameter, ultrafine fibers	Time-consuming process, low yield	Amphiphilic molecules, block copolymers	Suitable only for fundamental research and high-value-added micro-devices, not meeting the conditions for large-scale commercialization in outdoor apparel materials [37].
Template synthesis [38]	Size controllable, single fiber	High template cost, complex process	Various polymers and inorganic materials	Primarily serves academic research, standard sample preparation, or fields with special performance requirements. Due to cost and production limitations, it is difficult to apply to commercial clothing production [39].
Matrix Spinning [40]	Mild conditions, suitable for sensitive materials.	Low yield; matrix removal increases steps and costs	Biopolymers, hydrogels	Potential for applications in biomedical and other fields; for large-scale production of conventional outdoor clothing, it remains at the forefront of exploration, with technical and economic feasibility not yet mature [40].
Conventional Coatings	Mature process, low cost, high output, good waterproofness	Poor breathability, limited functionality, environmental concerns, heavy add-on	Polymer dispersions/solutions (PU, acrylic, PTFE)	Dominant in current mass market for basic waterproof apparel; faces challenge in high-end breathable and smart segments.

Table 2. Comparison of advantages, disadvantages, and applicability of different nanofiber preparation techniques.

Fabrication Techniques	Main Advantages	Main Limitations	Applicable Materials	Commercial Feasibility
Electrospinning [32]	Simple equipment, uniform fibers, capable of producing complex structures	Requires high-voltage electric field, limited production capacity	Various polymer solutions/melts	Mainstream approach in laboratory research and high-end specialty products. Still faces efficiency and cost challenges in the textile and apparel sector [33].
Air-jet spinning [34]	No electric field required, high yield	Fiber diameter distribution wide	High viscosity solution	Possesses industrialization potential, suitable for fields requiring large-scale production with less stringent uniformity demands. More appropriate for use as a foundational functional layer in apparel [34].
Centrifugal spinning [35]	High safety, large output	Complex equipment, disordered fibers	Polymer solution/melt	Suitable for large-scale production of coarser nanofiber/microfiber nonwoven fabrics; less competitive in the high-end membrane segment of outdoor apparel [36].
Self-assembly [37]	Precise diameter, ultrafine fibers	Time-consuming process, low yield	Amphiphilic molecules, block copolymers	Suitable only for fundamental research and high-value-added micro-devices, not meeting the conditions for large-scale commercialization in outdoor apparel materials [37].
Template synthesis [38]	Size controllable, single fiber	High template cost, complex process	Various polymers and inorganic materials	Primarily serves academic research, standard sample preparation, or fields with special performance requirements. Due to cost and production limitations, it is difficult to apply to commercial clothing production [39].
Matrix Spinning [40]	Mild conditions, suitable for sensitive materials.	Low yield; matrix removal increases steps and costs	Biopolymers, hydrogels	Potential for applications in biomedical and other fields; for large-scale production of conventional outdoor clothing, it remains at the forefront of exploration, with technical and economic feasibility not yet mature [40].
Conventional Coatings	Mature process, low cost, high output, good waterproofness	Poor breathability, limited functionality, environmental concerns, heavy add-on	Polymer dispersions/solutions (PU, acrylic, PTFE)	Dominant in current mass market for basic waterproof apparel; faces challenge in high-end breathable and smart segments.

For contextualizing the advancement of nanofiber membranes, a comparison with conventional coating technologies is imperative. Traditional coatings, such as polyurethane (PU) or polytetrafluoroethylene (PTFE) laminates/coatings, have dominated the waterproof apparel market for decades. Their primary advantages lie in proven scalability, robust waterproof performance, and relatively low cost. However, their dense, non-porous or microporous structures typically result in water vapor transmission rates below 5000 g·m⁻²·24 h⁻¹, creating a fundamental trade-off between waterproofness and breathability. Furthermore, integrating additional functions like intelligent thermal regulation, sensing, or high-efficiency filtration within a single coated layer is technologically challenging. The environmental footprint of solvent-based coating processes and the difficulty in recycling coated fabrics also present sustainability limitations. In contrast, nanofiber membranes, particularly electrospun ones, aim to redefine this paradigm by decoupling these performance trade-offs through designed porosity and multi-material integration.

Table 3. Comparison of performance parameters of different nanofiber preparation techniques.

Fabrication Techniques	Fiber Diameter Range	Production Efficiency	Relative Cost	Scalability	Fiber Quality
Electrospinning [41]	50 nm–5 μm	Moderate	Moderately high	Moderate	Uniform diameter, strong structural controllability
Air-jet spinning [42]	100 nm–10 μm	High	Low to moderate	High	Wide size distribution
Centrifugal spinning [43]	500 nm–20 μm	High	Low	High	Fibers are typically disordered
Self-assembly [44]	1–50 nm	Extremely low	High	Extremely low	Precise diameter, molecular-level control
Template synthesis [45]	20–500 nm	Low	High	Low	Highly controllable size and morphology
Matrix spinning [46]	10–500 nm	Low	Moderate	Low to medium	Wide size distribution

Table 3. Comparison of performance parameters of different nanofiber preparation techniques.

Fabrication Techniques	Fiber Diameter Range	Production Efficiency	Relative Cost	Scalability	Fiber Quality
Electrospinning [41]	50 nm–5 μm	Moderate	Moderately high	Moderate	Uniform diameter, strong structural controllability
Air-jet spinning [42]	100 nm–10 μm	High	Low to moderate	High	Wide size distribution
Centrifugal spinning [43]	500 nm–20 μm	High	Low	High	Fibers are typically disordered
Self-assembly [44]	1–50 nm	Extremely low	High	Extremely low	Precise diameter, molecular-level control
Template synthesis [45]	20–500 nm	Low	High	Low	Highly controllable size and morphology
Matrix spinning [46]	10–500 nm	Low	Moderate	Low to medium	Wide size distribution

Comparing the effects of these different spinning methods on the fiber-forming behavior, stacking morphology, and fiber production capacity of nanofibers is of great significance for selecting appropriate preparation techniques. Electrospinning has obvious advantages in fiber diameter control, structural diversity, and process flexibility, making it particularly suitable for laboratory research and small-batch production of high-performance products; whereas air-jet spinning and centrifugal spinning show more promise for large-scale production, suitable for mass production of products where fiber structure requirements are not extremely strict.

2.4. Construction Strategies for Multi-Level Structured Nanofiber Membranes

To meet the high demands for multifunctional integration in outdoor clothing, a single homogeneous nanofiber structure often fails to satisfy all performance requirements. Therefore, designing nanofiber membranes with multi-level structures through various advanced construction strategies has become a research hotspot. These strategies aim to regulate the structure of the fiber membrane from the micro to macro scales, thereby achieving optimization and integration of functions.

2.4.1. Precise Encapsulation of Multi-Axial Fiber Core–Shell Structures

Compared to simple fibers obtained by conventional uniaxial electrospinning, coaxial electrospinning technology can produce composite nanofibers with a core–shell structure. This special structure provides an ideal carrier for the effective encapsulation of functional substances. Coaxial electrospinning uses a specially designed coaxial spinneret, allowing two different polymer solutions to pass through the core and shell channels, respectively. Under the action of electric field force, they jointly form a jet, which eventually solidifies into core–shell structured nanofibers. Core–shell nanofibers are composed of two or more different materials, with the core layer completely wrapped by the shell layer, forming a microstructure similar to a “cable” [47].

This structure provides an ideal encapsulation carrier for functional components such as phase change materials, drugs, and bioactive ingredients. Taking the temperature control application in outdoor clothing as an example, phase change materials are encapsulated in the fiber core layer, while the shell polymer provides mechanical protection and shape fixation. When the ambient temperature reaches the melting point of the phase change material, the core layer material absorbs heat and undergoes a phase change, thereby forming a thermal buffer layer between the human micro-environment and the outside world, improving the thermal comfort of the clothing [48]. Similarly, in medical outdoor clothing, antibacterial or anti-inflammatory drugs can be encapsulated in the core layer, and the drug release rate can be controlled by selecting the shell polymer to achieve long-lasting protection.

In addition to the coaxial configuration, triaxial electrospinning can be further designed to construct a ternary composite structure with spatial gradient distribution, achieving precise spatial distribution and synergistic effects of multiple functional components. For example, in the design of photothermal conversion fiber membranes, photothermal materials are distributed in the core layer, moisture-wicking materials serve as the intermediate layer, and wear-resistant materials act as the outer shell, thereby integrating multiple functions within a single fiber system.

2.4.2. Porous/Beaded Fibers Increase Specific Surface Area and Roughness

By precisely controlling process parameters or solution composition, introducing porous or beaded structures into electrospun nanofibers can significantly increase their specific surface area and surface roughness, thereby providing enhanced functionality for high-end outdoor apparel. Specifically, the extremely high specific surface area greatly enhances the adsorption capacity of nanofiber membranes for water molecules and pollutant molecules, making these fiber membranes ideal candidates for efficient inner-layer materials. Simultaneously, the increased surface roughness can significantly alter the wettability of the fiber membrane; based on Wenzel and Cassie-Baxter theories, this property can be utilized to create superhydrophobic surfaces from intrinsically hydrophobic polymers, achieving water contact angles greater than 150° and sliding angles lower than 10°, thus endowing waterproof outdoor clothing with excellent self-cleaning properties [49]. Although beaded structures are traditionally viewed as defects, by controlling solution concentration or electric field strength, they can be strategically designed as beneficial features. In such applications, controlled beaded structures can improve the retention efficiency of particulate matter during filtration or serve as carriers for catalytically active sites, indicating that when these microstructures are precisely regulated, they can positively contribute to the material’s overall functional performance.

2.4.3. Special Wettability Surfaces Inspired by Lotus Leaves, Spider Silk, Etc.

Nature presents numerous surface structures with special wetting characteristics, such as the self-cleaning lotus leaf, the directional water collection of spider silk, and the water harvesting mechanism of desert beetles. These natural phenomena provide references for developing high-performance fiber membranes using electrospinning technology. In the case of lotus leaf biomimetics, its unique surface consists of micron-scale protrusions and nano-scale waxy crystals, forming a hierarchical rough structure. This micro-nano hierarchical structure significantly reduces the actual contact area with liquid droplets, endowing the material with excellent hydrophobic properties and self-cleaning functionality. Using electrospinning combined with subsequent processing techniques, similar micro-nano hierarchical structures can be constructed on fiber surfaces. Spider silk biomimetic research is also noteworthy; its periodic spindle-knot structure enables directional water transport. When moisture in the air condenses into water droplets, they are guided and transported along the fiber structure. Applying electrospinning processes combined with humidity control technology can replicate this special structure on nanofiber materials, significantly improving the moisture-wicking performance of outdoor apparel, promoting the directional migration of sweat from the skin to the external environment, thereby alleviating discomfort caused by moisture accumulation [50]. Inspired by biological structures such as rose petals, rice leaves, and butterfly wings in nature, researchers have developed biomimetic surfaces with directional fluid transport, selective permeability, and stimulus-responsive functions. This design approach, following the “structure-function” correlation principle, greatly enhances the application potential of smart outdoor textiles by finely tuning the liquid manipulation capabilities of nanofiber membranes.

2.4.4. Multifunctional Integrated Structures

To fully leverage the potential of nanofiber membranes in outdoor apparel, integrating them with composite structures and other functional materials is key to achieving multifunctional performance. Mainstream approaches include compounding with nanoparticles, combining with electrosprayed membranes, and integrating with traditional textiles.

Compounding with nanoparticles involves adding nanoparticles to the spinning solution or loading them onto the fiber surface through post-treatment, thereby endowing the fiber membrane with new functionalities. Commonly used nanoparticles include metal nanoparticles, metal oxides, carbon materials, and metal–organic frameworks. This composite technique imparts special functions to nanofiber materials by introducing nanoparticles. For instance, loading silver nanoparticles can provide antibacterial properties, which is particularly important for hygiene protection in outdoor clothing; loading TiO2 or ZnO nanoparticles can offer UV resistance, protecting the wearer from ultraviolet radiation; loading MXene or silver nanowires can enhance the conductivity of the fiber membrane, enabling electrothermal conversion or sensing functions; while loading MOFs materials can enhance the adsorption capacity for specific gas molecules [51].

Electrospraying involves adjusting process parameters so that polymer droplets do not fully form fibers during flight but instead deposit as micro-nano particles, forming a porous film. By alternating electrospinning and electrospraying, composite membranes with hierarchical pore channels can be constructed. Nanofibers provide mechanical support and basic breathability, while the micro-nano particles formed by electrospraying constitute a porous functional layer, serving as a functional surface or selective barrier that significantly improves the balance between waterproofing and moisture permeability of the membrane.

Laminating nanofiber membranes with traditional textiles compensates for the limited mechanical durability of nanofibers while preserving their high functional characteristics, typically forming a sandwich structure in outdoor apparel to achieve optimal protection and comfort. The composite method can involve multi-layer lamination or directly spinning nanofibers onto textile substrates. For example, laminating a waterproof and breathable nanofiber membrane with an outer fabric (providing abrasion resistance) and an inner fabric (providing comfort) through heat pressing or adhesive bonding to form a sandwich structure is a typical construction for outdoor clothing.

3. Research Progress on Multifunctional Integration of Nanofiber Membranes for Outdoor Clothing

3.1. High-Efficiency Waterproof and Moisture-Permeable

The waterproof and moisture-permeable function is the cornerstone of outdoor clothing, with its core principle being to block the penetration of liquid water while allowing water vapor to pass through smoothly, maintaining comfort and dryness inside the garment. Nanofiber membranes show great potential in this field due to their unique pore characteristics. The application and performance characterization of highly breathable and waterproof electrospun nanofiber membranes in outdoor sportswear are shown in Figure 4.

3.1.1. Mechanism Analysis

The waterproof and moisture-permeable functions of nanofibrous membranes are primarily achieved through two mechanisms: the hydrophilic-microporous synergistic effect and the Gibbs adsorption-evaporation mechanism.

The hydrophilic-microporous synergistic mechanism combines physical interception and chemical transport processes. The nanofibrous membrane possesses abundant microporous structures internally, with pore diameters typically in the range of 0.1–10 μm, which is much larger than the diameter of water vapor molecules but far smaller than the diameter of raindrops. This size difference allows water vapor to pass through freely while liquid water is physically blocked. Simultaneously, the built-in hydrophilic components actively adsorb water molecules, enhancing moisture permeability efficiency through a continuous adsorption–desorption “hopping” transport along the molecular chains [52]. This synergistic effect enables suitable nanofibrous membranes to provide both high hydrostatic pressure resistance and maintain high moisture permeability.

The Gibbs adsorption-evaporation mechanism explains the moisture permeability process from a thermodynamic perspective. According to Gibbs adsorption theory, hydrophilic surfaces have a strong adsorption effect on water molecules, forming an adsorption layer. When a humidity gradient exists between the inside and outside of the garment, water molecules adsorb from the high chemical potential side, continuously transport through the material’s interior, and desorb on the low chemical potential side, completing the “adsorption-diffusion-desorption” cycle [53]. The enormous specific surface area of the nanofiber structure significantly enhances this adsorption-driven transport by providing abundant active adsorption sites. Inspired by the gradient wettability design found in natural systems such as plant leaves, constructing bilayer fiber membranes with asymmetric hydrophilicity not only maintains strong waterproof performance but also promotes directional moisture transport, thereby delivering excellent moisture management performance for high-end outdoor apparel.

3.1.2. Implementation Strategies

To achieve efficient waterproof and moisture-permeable functionality, research focuses on the rational selection of material systems and the precise design of nanofiber membrane structures. In terms of materials, thermoplastic polyurethane (TPU), polyvinylidene fluoride (PVDF), and their copolymers are widely adopted due to their tunable segment structures, excellent film-forming properties, and inherent hydrophobic characteristics. TPU can balance its mechanical properties and moisture permeability by adjusting the ratio of soft and hard segments, while the PVDF family, with its low surface energy and high surface potential, provides good waterproofness while also enhancing the electrostatic adsorption capacity for particulate matter, enabling multifunctional integration [54]. In recent years, environmentally friendly bio-based material composite systems, such as cellulose acetate (CA) and polyvinyl alcohol (PVA), have also shown great potential. For example, CA/PVA composite nanofiber membranes cross-linked with glutaraldehyde vapor exhibit significantly improved water resistance, with the mass loss rate after 24 h in water decreasing from 70.76% before modification to 7.28%, while the breaking strength increases from 0.76 MPa to 1.51 MPa [55]. At the structural design level, cutting-edge strategies primarily involve constructing pore size gradient distributions and Janus asymmetric structures.

Pore size gradient design, by controlling the pore size along the thickness direction of the fiber membrane, enables directional and rapid moisture transport. Large pores on the inner side preferentially adsorb moisture, the middle layer with gradually changing pore sizes regulates the transport rate, and small pores on the outer side effectively block liquid water. The Janus structure, by endowing the two sides of the membrane with opposite wettability, creates a strong “unidirectional moisture conduction” effect, actively pumping sweat from the skin side to the external environment while preventing the reverse penetration of external water. Cheng et al. [56] developed a one-step preparation technique that successfully produced nanofiber membranes with a uniform microporous structure featuring pore sizes smaller than 30 nm and porosity exceeding 70%, achieving a hydrostatic resistance of up to 10,000 mmH₂O and a moisture permeability of 10,000 g·m⁻²·24 h⁻¹. This signifies that through the synergistic innovation of materials and structure, the performance boundaries of nanofiber membranes in the field of outdoor apparel are continuously being pushed forward.

3.1.3. Performance Comparison and Trade-Off Analysis

The performance of nanofiber membranes must be evaluated not only against high-end (ePTFE) membranes but also against the benchmark of conventional coatings which are prevalent in the industry. As an emerging waterproof and moisture-permeable platform, the performance of nanofiber membranes needs to be systematically benchmarked against traditional commercial membranes represented by expanded polytetrafluoroethylene (ePTFE), such as Gore-Tex, and conventional textile materials, to clarify their technological positioning and development potential. Although the preparation process of nanofibers still faces challenges in batch consistency and structural uniformity, resulting in greater performance fluctuations compared to traditional materials, the controllability of their performance has been significantly improved through the optimization of spinning parameters and post-treatment processes. Comparative data on the waterproof and moisture-permeable performance of different nanofiber membranes and commercial membranes are shown in

Table 4. Comparison of Waterproof and Moisture-Permeable Performance Between Different Nanofiber Membranes and Commercial Membranes.

Material Type	Hydrostatic Pressure (kPa)	Moisture Vapor Transmission Rate (g·m−2·24 h−1)	Contact Angle (°)	Key Features
TPU Nanofiber Membrane	85–120	8000–12,000	130–145	High elasticity, good comfort
PVDF Nanofiber Membrane	110–150	6000–10,000	140–155	Excellent chemical resistance, high waterproof performance
CA/PVA Composite Membrane	70–100	5000–8000	125–140	Biodegradable, environmentally friendly
PTFE Nanofiber Membrane	130–180	9000–13,000	150–165	Excellent durability, long-term stability
Commercial Gore-Tex Membrane	90–140	8000–10,000	135–150	Mature technology with balanced comprehensive performance

[57]. From a comprehensive performance perspective, traditional commercial membranes, optimized over decades, have established a reliable balance in the “waterproofness-moisture permeability-durability” triangle; whereas nanofiber membranes aim to redefine this balance by leveraging their structural advantages. In terms of core performance parameters, nanofiber membranes prepared via electrospinning, especially those based on thermoplastic polyurethane (TPU) or polyvinylidene fluoride (PVDF) systems, typically exhibit excellent moisture permeability due to their highly interconnected microporous structure. Their water vapor transmission rate (WVTR) can exceed 10,000 g·m⁻²·d⁻¹, a value significantly higher than that of traditional ePTFE membranes. a value that is 2 to 5 times higher than that of most conventional dense coatings while still maintaining competitive hydrostatic pressure resistance. To achieve such high moisture permeability, nanofiber membranes typically rely on high porosity and interconnected pores, but this may come at the expense of some hydrostatic pressure and intrinsic mechanical strength. However, in the key indicator of hydrostatic pressure (HH), which measures water resistance, traditional ePTFE membranes still maintain an advantage due to their inherent hydrophobicity and robust node-fibril structure, with HH values consistently above 100 kPa. Although single-layer nanofiber membranes can improve their water resistance through surface hydrophobic modification or by compositing with dense barrier layers, achieving HH values in the practical range of 80–100 kPa, such post-treatments (e.g., cross-linking or compositing) may slightly reduce moisture permeability or increase weight. In terms of mechanical properties, traditional textile materials (such as nylon or high-density polyester fabrics) typically exhibit higher tensile strength, tear resistance, and abrasion resistance due to mature spinning and weaving processes. In contrast, nanofiber membranes, due to their fine fiber diameter and low packing density, currently face significant shortcomings in mechanical durability, particularly in resistance to repeated hydraulic impact, bending, and abrasion. This remains a key obstacle to transitioning nanofiber membranes from laboratory settings to durable products [58]. However, nanofiber membranes possess significant advantages in terms of lightweight design, breathability, and functional integrability, which are difficult to match with traditional dense coatings or laminated fabrics. The superior waterproofness of ePTFE membranes stems from the extremely low surface energy of their perfluorocarbon chains and their unique stretched microstructure. In contrast, the high moisture permeability of nanofiber membranes benefits from their high porosity and interconnected channels, which provide low-resistance pathways for water vapor molecule diffusion. Nanofiber membranes offer unique advantages in lightweight design and wearing comfort: their areal density can be controlled within the range of 5–20 g/m², which is significantly lower than traditional laminated fabrics, benefiting the flexibility and heat dissipation of the garment; by constructing a Janus asymmetric structure or pore size gradient, directional moisture transport can be achieved, preventing sweat accumulation and thereby providing superior microclimate regulation in dynamic sports scenarios, demonstrating better wearing comfort compared to traditional commercial membranes with symmetric structures [59]. To overcome mechanical durability challenges, future solutions include developing tougher polymers (such as polyimide), implementing effective chemical/physical cross-linking, and designing multilayer composite structures with enhanced interfaces. In summary, current nanofiber membranes have demonstrated significant advantages in moisture permeability efficiency, lightweight potential, and structural/functional designability, making them particularly suitable for high-end sportswear applications that are sensitive to breathability and weight. However, they still lag behind traditional materials in terms of long-term mechanical stability, process controllability, and large-scale production costs. Through continuous material innovation, structural optimization, and process standardization, nanofiber membranes are expected to achieve broader practical applications in the outdoor apparel field.

3.2. Thermal Comfort Management

Outdoor environments experience drastic temperature changes, making efficient thermal comfort management one of the core requirements for outdoor clothing. Through ingenious material selection and structural design, nanofiber membranes can achieve a combined passive and active thermal management strategy.

3.2.1. Passive Thermal Management

Nanofiber membranes offer two complementary physical mechanisms for efficient passive human thermal management: static thermal insulation and radiative cooling. The insulation performance originates from the closed or semi-closed nanopores formed by the high porosity within the nanofiber membrane. These structures can effectively trap a large amount of static air, forming an effective thermal barrier that suppresses heat conduction and convection. Studies have shown that nanofiber membranes with a thickness of only 100 μm can achieve an overall thermal conductivity as low as 0.033–0.040 W·m-1·K⁻¹, meeting the lightweight requirements of outdoor apparel while providing excellent insulation [60]. On the other hand, radiative cooling, as an emerging zero-energy thermal regulation strategy, utilizes the nanofiber membrane as a functional carrier. By incorporating wide-bandgap nanomaterials with high reflectivity in the solar spectrum and maintaining high emissivity in the mid-infrared band, it achieves cooling through selective emission and reflection of thermal radiation wavelengths. This nanofiber membrane material can synergistically promote radiative dissipation of body heat and effectively reflect solar radiation [61]. For instance, integrating SiO₂ nanoparticles into the fiber network has achieved sub-ambient cooling effects under direct sunlight. These two mechanisms collectively demonstrate the great potential of nanofiber membranes as an advanced thermal management platform, providing innovative solutions to address thermal comfort challenges in complex outdoor environments.

3.2.2. Active Thermal Management

In addition to passive thermal management, nanofiber membranes can also be integrated with active thermal management functions, enabling on-demand thermal regulation through external energy stimulation.

Photothermal conversion utilizes solar energy, a clean energy source, by integrating photothermal materials to convert sunlight into thermal energy. Commonly used photothermal materials include carbon materials, noble metal nanoparticles, and semiconductor materials. These materials exhibit strong absorption in the visible and near-infrared regions, converting light energy into heat through mechanisms such as localized surface plasmon resonance or interband electron transitions. For example, incorporating reduced graphene oxide (rGO) into nanofibers can produce smart textiles with efficient photothermal conversion performance, which rapidly heat up under sunlight exposure, providing an additional heat source for outdoor activities in cold environments [62].

Electrothermal conversion, on the other hand, achieves heating by integrating conductive materials that generate Joule heat under an applied electric current. Commonly used conductive fillers include conductive polymers, MXene, and silver nanowires. Such electrothermal nanofiber membranes can be combined with miniature power supplies to enable low-power heating, and through material design, achieve uniform control of the temperature field, making them suitable for outdoor clothing in extremely cold environments [63].

As shown in Figure 5, in actual validation experiments where a volunteer wore nanofiber membrane clothing in (a) high-temperature and (b) cold environments, compared to commercial textiles, the nanofiber membrane clothing exhibited lower temperatures in high-temperature environments (Figure 5a) and higher temperatures in colder environments (Figure 5b), attributed to its rapid thermal response and efficient energy storage/release mechanisms. Particularly in summer, traditional textiles may cause thermal discomfort during temperature changes, but clothing containing nanofiber membrane materials can effectively address this issue. The synergistic application of passive and active thermal management strategies enables nanofiber membranes to adapt to diverse outdoor environmental demands, providing comprehensive thermal comfort protection for the wearer.

3.3. Enhanced Durability and Protection

Outdoor clothing often faces harsh environmental challenges, and enhancing durability and protection is key to expanding its application scope. A schematic diagram of the materials, structure, and characteristics of nanofiber membranes in outdoor sportswear is shown in Figure 6. Outdoor sportswear prepared using different nanofiber composite membranes exhibits high durability, UV protection functionality, comfort, physiological monitoring, and antibacterial properties.

3.3.1. Mechanical Performance Enhancement and Key Parameter Analysis

In the application of nanofiber membranes in outdoor apparel, mechanical durability is one of the key performance indicators determining whether they can transition from the laboratory to the market. Although the structural characteristics of nanofiber membranes (such as porosity and fiber orientation) affect the final functionality of the garment, mechanical parameters such as tensile strength, elongation at break, tear resistance, abrasion resistance, and fatigue resistance are directly related to the service life and reliability of the apparel. In recent years, researchers have significantly improved the mechanical properties of nanofiber membranes through various strategies, including cross-linking techniques, fiber blending, and structural design [65].

The use of cross-linking methods can significantly enhance the mechanical properties of materials [66]. Chemical cross-linking, such as using glutaraldehyde to cross-link polyvinyl alcohol nanofiber membranes, can increase their tensile strength from approximately 5 MPa for pure PVA membranes to over 15 MPa, while maintaining elongation at break within the practical range of 80%–150%. Physical cross-linking, such as inducing hydrogen bonding and chain interpenetration between polyurethane nanofibers through hot-pressing treatment, can significantly improve tear resistance, with tear strength increasing by 2–3 times. While cross-linking enhances strength, it is often accompanied by a slight reduction in material flexibility or moisture permeability, reflecting the challenge of performance trade-offs [67].

Fiber composite technology, by incorporating high-rigidity or high-strength components, can achieve synergistic reinforcement effects [68]. For example, adding a small amount of carbon nanotubes to polyacrylonitrile spinning solutions can increase the tensile modulus of the resulting composite nanofiber membrane from 0.5 GPa to 2.5 GPa, while simultaneously enhancing electrical conductivity, which is beneficial for multifunctional integration. Another typical case is polyimide nanofiber membranes, which inherently exhibit excellent heat resistance and mechanical strength but are relatively brittle. By blending them with elastic fibers to form an interwoven network structure through composite spinning, not only are the high-strength characteristics of the material maintained, but the elongation at break is also significantly increased from the original 10% to over 100%, thereby effectively optimizing their performance in practical applications [69].

Structural design also has a decisive impact on mechanical performance. Aligned nanofiber membranes exhibit higher tensile strength and modulus in the fiber alignment direction, with anisotropy ratios ranging from 3:1 to 10:1, which enables directional reinforcement design in different stress-bearing areas of garments [70]. By adopting a multi-layer composite approach, such as laminating ultra-thin fabric meshes on both sides of the nanofiber film or alternating electrospinning with spray deposition, crack propagation can be effectively hindered, thereby enhancing the material’s puncture resistance and hydrostatic pressure fatigue performance [71].

Although the aforementioned methods effectively improve the mechanical properties of nanofiber membranes, most pure nanofiber materials still fall short compared to traditional high-density woven fabrics. Therefore, current research trends focus on developing new high-strength polymer systems, optimizing composite interface bonding, and exploring self-healing mechanisms to extend service life. The precise evaluation and enhancement of these mechanical parameters are directly related to whether nanofiber membranes can meet the durability standards for outdoor apparel, representing a critical technical challenge that must be overcome for their commercialization.

3.3.2. Anti-UV Functionality

Outdoor apparel needs to provide effective ultraviolet (UV) protection to reduce skin damage caused by prolonged outdoor activities. Nanofiber membranes achieve good anti-UV capabilities by integrating wide-bandgap metal oxide nanoparticles as UV absorbers. These materials can effectively block UV radiation through the synergistic action of three mechanisms: absorption, reflection, and scattering [72]. These wide-bandgap semiconductor materials exhibit strong absorption of UV light while remaining transparent to visible light, thus not affecting the appearance of the clothing. Particularly when the size of these materials is reduced to the nanoscale, the quantum confinement effect enhances their UV absorption capacity while minimizing scattering effects. These nanoparticles have good dispersion stability and can be uniformly distributed within the nanofiber matrix, forming an effective UV shielding network [72]. Structural design also influences the UV protection performance of nanofiber membranes. By constructing multi-layer composite structures, such as placing a functional layer containing nanoparticles between two layers of pure polymer fibers, not only can the UV protection factor rating be improved, but the material’s durability and wearing comfort can also be enhanced. This design prevents direct shedding of nanoparticles while maintaining the original breathability and flexibility of the fiber membrane.

3.3.3. Antibacterial and Antimicrobial Functions

Outdoor clothing, due to prolonged exposure to damp and sweaty environments, easily becomes a breeding ground for microorganisms. Nanofiber membranes provide lasting protection by loading various antimicrobial agents. Current primary antibacterial strategies include silver-based nanomaterials, quaternary ammonium compounds, and natural antimicrobial agents.

Silver nanoparticles are the most widely used inorganic antimicrobial agents due to their broad-spectrum antibacterial properties and long-term stability. Their antibacterial mechanism primarily involves the continuous release of silver ions, which bind to sulfhydryl groups in bacterial proteins, disrupting cell membrane integrity and enzyme systems, inhibiting respiration and metabolic activities, and ultimately leading to cell death [73]. These silver-based nanomaterials exhibit broad-spectrum inhibitory effects against various bacteria and fungi. Quaternary ammonium compounds act through electrostatic interactions between their positive charges and the negative charges of bacterial cell membranes, disrupting membrane integrity and causing bacterial death. Natural antimicrobial agents, such as chitosan, tea polyphenols, and plant essential oils, have garnered widespread attention due to their good biocompatibility, biodegradability, and natural antimicrobial properties. The amino groups in chitosan molecules carry a positive charge, enabling them to adsorb onto the negatively charged surfaces of bacteria, interfering with cell membrane functions and inhibiting mRNA and protein synthesis [74]. When used synergistically with silver-based nanomaterials, chitosan can form a stronger antibacterial network, showing great promise in the antibacterial protection of outdoor clothing.

3.4. Intelligent Response and Sensing

With the development of wearable electronic technology, intelligent response and sensing functions have become a new direction for outdoor clothing, and nanofiber membranes, as flexible carriers, demonstrate unique advantages in this field.

3.4.1. Stimulus-Responsive Membranes

This represents a frontier where nanofiber membranes distinctly surpass the capabilities of conventional coatings. While traditional coatings are largely static in their properties post-application, nanofiber membranes can be engineered to dynamically respond to environmental stimuli. Intelligent responsive nanofiber membranes can perceive changes in environmental conditions and dynamically adjust their performance, enabling dynamic regulation of functions related to outdoor clothing. Common types of stimulus-responsive nanofiber membranes and their performance characteristics are shown in

Table 5. Stimulus-Response Types and Performance Characteristics of Nanofiber Membranes.

Response Type	Representative Materials	Stimulus Conditions	Response Mechanisms	Performance Changes
Temperature Response	PNIPAm and its Copolymers	Temperature Exceeds LCST	Hydrophilic-Hydrophobic Transition	Pore structure variation, Ag+ controlled release
Humidity responsiveness	Methyl cellulose/IPN hydrogel	Relative humidity 50%–100%	Asymmetric swelling/shrinkage	Directional moisture transport, breathability regulation
pH responsiveness	Chitosan/polyacrylic acid	pH varies within the range of 4–8	Protonation/Deprotonation	Pore size variation, controlled drug release
Photothermal response	Graphene/PNIPAm composite	UV-visible light irradiation	Photothermal conversion induced phase transition	Reversible wettability, color change

. Among these responsive materials, temperature- and humidity-responsive materials have become research hotspots due to their close association with the outdoor environment [75].

Thermosensitive materials offer unique advantages in thermal management for outdoor clothing. Poly(N-isopropylacrylamide) (PNIPAm) and its derivatives are the most representative thermosensitive polymers. Their molecular chains contain both hydrophilic amide groups and hydrophobic isopropyl groups, exhibiting reversible temperature-dependent phase transition behavior. When the ambient temperature is below the lower critical solution temperature (LCST), PNIPAm chains extend through hydrogen bonding with water molecules, and the membrane remains in a hydrophilic state; when the temperature exceeds the LCST, hydrogen bonds are disrupted, the molecular chains rapidly dehydrate and contract, transitioning to a hydrophobic state. This phase transition not only alters the membrane’s wettability but also regulates the pore structure, enabling automatic adjustment of breathability [76].

Humidity-sensitive materials are equally important for comfort management in outdoor clothing. Materials such as polyelectrolytes can undergo conformational changes in their chain segments under varying humidity levels, thereby regulating the permeability of nanofiber membranes. This humidity-sensitive mechanism primarily stems from the microscopic arrangement of hydrophilic/hydrophobic regions within the fibers. When environmental humidity is low, the fiber membrane maintains windproof and moisture-resistant properties; when environmental humidity increases, the hydrophilic regions expand significantly more than the hydrophobic regions, generating asymmetric stress that alters fiber curvature and channel size, thereby accelerating sweat expulsion [77].

Integrating temperature-sensitive and humidity-sensitive materials into the same nanofiber system can create multimodal responsive smart clothing. For example, interpenetrating network (IPN) hydrogel nanofibers based on methylcellulose retain the thermoreversible gel properties of methylcellulose while introducing humidity responsiveness through host-guest crosslinking. This dual-response system can automatically adjust pore size and surface energy in response to increased body temperature or sweat secretion, achieving dynamic optimization of breathability and providing outdoor athletes with more comfortable personal microclimate management.

3.4.2. Integrated Sensing

Integrating conductive nanofibers into outdoor clothing enables real-time monitoring of the wearer’s physiological signals and motion status, representing a crucial direction for the development of smart outdoor apparel. Conductive nanofibers used for sensing are typically fabricated by incorporating carbon materials, metal nanowires, or conductive polymers [78]. A schematic diagram of physical signal sensing through electrospun nanofiber composite sensors is shown in Figure 7. These fiber-based sensors can not only detect various physiological signals but also achieve self-powered operation when combined with energy harvesting systems, significantly enhancing the safety and convenience of outdoor activities.

Sensors based on the piezoelectric effect are fabricated by compounding polyvinylidene fluoride-trifluoroethylene with barium titanate (BTO) nanoparticles through electrospinning to form micro-textured fiber structures. Their piezoelectric performance originates from the polymer matrix crystal phase transformation induced by BTO nanoparticles and the larger specific surface area provided by the micro-textured structure, exhibiting high sensitivity and rapid response characteristics. Integrating such sensors into key areas of outdoor clothing enables real-time monitoring of various physiological parameters, including arterial pulse, breathing patterns, eyelid activity, joint movements, and plantar pressure distribution [78]. In terms of respiratory monitoring, piezoresistive sensors utilize hydrogen bonding between MXene/cellulose nanofibers and gelatin reinforcement layers, along with interlayer energy dissipation mechanisms, to construct stable conductive networks, achieving high mechanical durability and accurate recognition of different breathing patterns. Meanwhile, hydrovoltaic energy harvesting technology leverages the asymmetric wettability of fiber surfaces to generate electricity through directional water molecule flow and solid–liquid interface interactions in sweat or high-humidity environments, providing self-powering capability for the sensing system. Furthermore, nanofiber sensors can be integrated with GPS, inertial measurement units, and environmental sensors to build multifunctional monitoring systems capable of simultaneously tracking motion trajectories, posture changes, and environmental parameters, thereby achieving comprehensive perception and safety assurance of the wearer’s physiological status and external environment during high-intensity outdoor activities.

3.5. Sustainability Exploration

3.5.1. Source Reduction and Process Optimization

Faced with increasingly severe plastic pollution and resource depletion issues, developing nanofiber membranes based on biodegradable polymers for outdoor clothing has become an important research direction. Bio-based materials such as polylactic acid, polyhydroxyalkanoates, cellulose, and their derivatives, sourced from renewable resources and capable of degrading into harmless substances in specific environments after use, demonstrate significant green recycling potential. In this context, research on nanofiber membranes for outdoor clothing must comprehensively consider their full lifecycle environmental compatibility while pursuing multifunctional integration. At the material source level, adopting bio-based or biodegradable polymers to replace traditional petroleum-based polymers helps reduce the carbon footprint at the root and provides the possibility for controlled biodegradation after material disposal [79]. In terms of preparation processes, green improvements focus on promoting water-based electrospinning technologies or low-toxicity recyclable solvent systems to replace traditional toxic organic solvents, and exploring low-energy spinning methods such as needleless electrospinning, thereby enhancing the safety and sustainability of the production process [80]. During the usage phase, constructing highly durable surface structures or introducing self-healing mechanisms enhances the mechanical stability and anti-fouling performance of nanofiber membranes, effectively extending their service life and reducing resource waste and environmental burden caused by premature failure [81]. Therefore, systematically integrating material selection, green preparation, and usage maintenance strategies is the key pathway to achieving full-chain environmental friendliness for outdoor clothing nanofiber membranes, from raw materials to disposal.

3.5.2. Recycling and Reuse of Membrane Materials

The large-scale application of nanofiber membranes in outdoor clothing must establish an effective recycling and reuse system. Currently, researchers primarily address the recycling of nanofiber membranes through three approaches: chemical recycling, physical reuse, and biodegradation. Chemical recycling focuses on depolymerizing discarded nanofiber membranes into original monomers or other valuable chemicals through hydrolysis or alcoholysis processes, which can then be used for reproduction. For cellulose-based nanofiber membranes, enzymatic catalysis can selectively degrade the amorphous regions to obtain high-purity cellulose nanocrystals, which are used to prepare high-performance composite materials. The physical reuse strategy involves processing discarded nanofiber membranes from used clothing into new products directly through steps such as cleaning, shredding, and re-pelletizing. Biological recycling utilizes the specific degradation capabilities of enzymes or microorganisms to selectively decompose certain components, thereby recovering valuable materials [81].

From a product design perspective, adopting a modular design concept can also significantly enhance the sustainability of outdoor clothing. By separating the nanofiber membrane as a replaceable component from the garment base, consumers can replace the functional membrane individually based on wear and tear, rather than discarding the entire garment. This design concept not only extends the overall lifespan of the product, reduces resource consumption, but also lowers the environmental cost throughout the entire lifecycle.

Life cycle assessments indicate that although the production cost of bio-based nanofiber membranes may be higher than that of traditional petroleum-based materials, their environmental advantages in the waste treatment phase are significant. By optimizing production processes, increasing the proportion of renewable energy, and establishing a comprehensive recycling system, the environmental impact of nanofiber membranes can be further reduced, providing support for the green development of the outdoor clothing industry.

4. Application of Nanofiber Membranes in Outdoor Sportswear

The cutting-edge breakthrough in the field of outdoor sportswear is reflected in the application of nanofiber membranes, an innovative material that holds significant value due to its unique structure. Its advantages primarily stem from three aspects: an extremely large surface area, adjustable pore characteristics, and convenient modification capabilities. Leveraging these unique strengths, this technology can effectively resolve the inherent conflicts among multiple performance aspects in outdoor clothing, such as waterproofing, breathability, and temperature regulation. In particular, the use of advanced processes like electrospinning, combined with multi-axial, porous, and biomimetic structural designs, enables precise control over the properties of nanofiber membranes. Before the trend of lightweight outdoor gear became popular, most people only regarded lightweight outdoor equipment as simple sun-protective clothing. As outdoor sports categories have become more specialized, outdoor sportswear has gradually evolved to include six essential core elements (as shown in Figure 8). These multifunctional lightweight products demonstrate advantages such as versatility, portability, thoughtful design, and strong adaptability. They feature properties like windproof and rainproof capabilities, breathability and moisture-wicking, and lightweight portability, significantly enhancing functional diversity, wearing comfort, and storage convenience, ensuring users enjoy a free and unrestricted wearing experience.

4.1. Application of Nanofiber Membranes in Extreme Outdoor Sportswear

High-altitude mountaineering, polar expeditions, and other extreme outdoor activities face severe environmental challenges, primarily characterized by persistent low temperatures, strong winds, heavy snowfall, and other harsh weather conditions, as well as the physical exertion from intense exercise. These specialized environments impose extremely high demands on professional protective gear, which must not only effectively resist wind and snow intrusion under extreme static conditions but also maintain breathability during high-intensity activities to promptly expel large amounts of sweat vapor, achieving a perfect balance between protection and comfort (as shown in Figure 9). Although traditional laminated materials possess excellent waterproof and breathable properties, their performance improvement potential is nearing its limit, and they struggle to achieve multifunctional integration. In contrast, nanofiber membranes with finely controllable microstructures demonstrate outstanding potential for multifunctional integration, opening new pathways for the innovative development of high-performance sportswear [82].

4.1.1. Design Strategies for Addressing the Conflict Between Extreme Protection and Moisture Permeability

Under extreme conditions, clothing fabrics must possess dual characteristics: effectively blocking liquid water penetration to withstand sustained high pressure while rapidly expelling sweat vapor to prevent inner garment dampness and subsequent hypothermia. Utilizing the electrospinning process allows precise control over the pore size and distribution density of fiber membranes, enabling pore structures that block water molecule penetration while ensuring smooth passage of water vapor molecules. This refined pore structure design significantly enhances the material’s waterproof and breathable performance [83]. Adjusting key parameters of electrospinning enables the preparation of porous nanofiber membranes, whose abundant pore networks create favorable conditions for water molecule diffusion, coupled with excellent hydrostatic pressure resistance, with performance indicators significantly surpassing those of conventional materials [84]. Inspired by the self-cleaning properties of lotus leaves, researchers have employed multi-scale rough surface construction techniques combined with low-energy surface material modifications to successfully develop nanofiber membranes with superhydrophobic properties [85]. This unique structure prevents liquids from spreading and penetrating the membrane surface, allowing them to slide off quickly, significantly enhancing the material’s protective performance under freezing rain or snow conditions. Research focus has shifted to dual-sided heterogeneous structure designs [86]. This innovative configuration gives the membrane inner layer hydrophilic properties for efficient sweat absorption while maintaining a hydrophobic outer layer to block external liquid penetration. Leveraging directional moisture transport mechanisms creates unidirectional transmission dynamics, achieving dynamic sweat management that only expels without absorbing, which is crucial for quickly maintaining skin dryness during exercise intervals [87].

4.1.2. Enhanced Thermal Management Capability in Extreme Environments

Extreme cold is the primary hazard under harsh conditions, and the thermal regulation design using nanofiber composite membranes has significantly improved the survival performance of protective clothing. By combining passive insulation with active heating technology, nanofiber membranes efficiently trap static air due to their porous structure, creating an excellent thermal barrier with a thermal conductivity as low as 0.03 W/m·K, comparable to top-tier down products [88]. This advantage has prompted researchers to integrate active heating devices, opening up innovative research pathways. Conductive networks constructed from efficient electrothermal conversion materials such as MXene or silver nanowires are incorporated into nanofiber membranes through compounding or surface modification, enabling rapid Joule heating at low driving voltages for precise and controllable localized heating [89]. This active temperature control component works synergistically with the passive insulation properties of the substrate to effectively meet thermal retention needs in sudden low-temperature environments or prolonged static scenarios. In high-altitude areas with intense solar radiation, mountaineers often face sudden increases in perceived temperature. Researchers have developed cooling functional membrane materials by incorporating special particles into the nanofiber matrix that efficiently reflect solar radiation while strongly emitting mid-infrared radiation. This innovative material can significantly reduce the surface temperature of mountaineering gear under direct sunlight, effectively preventing overheating due to the combined effects of internal and external heat sources.

4.2. Application of Nanofiber Membranes in Long-Distance Trail Sports Apparel

Long-distance trail sports, such as 100 km trail running, multi-day hiking, and long-distance mountain biking, are characterized by prolonged activity duration, high metabolic heat production, significant fluctuations in sweating rates, and the need for athletes to carry a certain amount of equipment. These characteristics determine that the priority for clothing performance is extreme moisture wicking and breathability, lightweight design, dynamic thermal and moisture comfort management, while also providing adequate wind and water protection (as shown in Figure 10). Nanofiber membrane technology, through its precise structural design and multifunctional integration capabilities, offers an ideal technical pathway to achieve this complex balance. Ultra-long-distance outdoor endurance events, including 100 km trail races, multi-day treks, and mountain biking, are notably characterized by extended activity periods, vigorous heat metabolism, drastic variations in sweat output, and participants needing to carry essential gear. Based on these traits, the prioritization criteria for clothing performance become primarily focused on efficient moisture management and breathability, weight reduction, and dynamic regulation of temperature and humidity, while also addressing the need for wind and water resistance [90]. The application of nanofiber membrane technology, leveraging its precise construction and multifunctional integration advantages, provides the optimal solution to resolve these multiple conflicting requirements.

4.2.1. Achieving Ultimate Moisture Permeability and Dynamic Comfort Management

During prolonged physical activities, maintaining breathability in the microclimate next to the skin is crucial for enhancing athletic comfort and performance, while also effectively preventing abnormal body temperature [91]. Nanofiber membranes, due to their unique microstructure, possess a rich network of pores and an ultra-large specific surface area. These characteristics significantly reduce the transport resistance of water vapor molecules, creating ideal conditions for rapid moisture expulsion. By optimizing the compactness of fiber alignment and the characteristics of the pore structure, membrane products with excellent moisture permeability can be developed. This superior breathability effectively expels sweat vapor generated during exercise. Directional moisture transport and humidity regulation, using Janus dual-layer structured nanofiber membranes, hold significant value in the field of cross-country sportswear. Their asymmetric structure—hydrophilic on the inner layer and hydrophobic on the outer layer—creates a notable capillary effect, prompting rapid absorption of sweat from the skin and its directional transport to the outer layer for evaporation, effectively maintaining dryness and comfort in the garment’s contact areas. This active perspiration system, through a dynamic regulation mechanism, successfully eliminates the sticky discomfort caused by sweat accumulation during exercise, greatly improving the wearing experience.

4.2.2. Lightweight Design and Adaptive Thermal Management

In the field of long-distance cross-country equipment, lightweighting is a key criterion [92]. Nanofiber membranes hold advantages due to their inherent properties and can also achieve intelligent temperature control through material engineering. The ultra-thin integrated characteristics of nanoscale fiber membranes prepared by electrospinning technology have a thickness of only a few micrometers and are extremely lightweight. When combined with micro-denier fabrics, the protective performance of the clothing is significantly enhanced while the weight remains almost unchanged. This lightweight structure can effectively reduce the physical exertion of athletes. Cross-country sportswear design emphasizes passive temperature control solutions, prioritizing efficient passive cooling mechanisms due to weight constraints. By integrating nanomaterials such as SiO₂ and boron nitride, which possess excellent solar reflectance and infrared radiation properties, into nanofibers, the temperature rise of sportswear under direct sunlight can be significantly reduced [93]. This passive cooling technology can create a continuously comfortable thermal environment for outdoor long-distance runners, with its importance being particularly prominent in sports involving prolonged exposure to open areas. Using coaxial electrospinning technology, paraffin or bio-based phase change materials (PCMs) can be encapsulated in the fiber core to produce nanofibers with temperature-regulating functions [94]. These smart materials can absorb heat and melt when the athlete’s skin temperature rises, preventing localized overheating. When the temperature drops, they release heat through solidification, providing insulation. This thermal buffering characteristic is especially suitable for environments with variable mountain climates and significant day-night temperature differences.

4.3. Application of Nanofiber Membranes in Urban Outdoor Sportswear

The distinctive feature of urban outdoor sports lies in the organic integration of exercise, commuting, and daily life scenarios [95]. This characteristic poses unique challenges for clothing design, requiring not only basic sports protection and comfort but also meeting the demands of fashion sense in daily wear, functional integration, and environmental requirements, which clearly differ from traditional wilderness equipment (as shown in Figure 11). Leveraging the excellent processability, controllable structural properties, and ease of functionalization of nanofiber membranes, this technology stands as the optimal choice for developing multifunctional urban outdoor clothing.

4.3.1. Integrated Fusion of Protection, Moisture Permeability, and Esthetics

Urban outdoor clothing for daily wear needs to combine water repellency and sweat stain resistance while maintaining a fashionable and esthetically pleasing design style. The ultrafine fiber membranes produced via electrospinning technology possess excellent thinness and flexibility. When combined with trendy fabrics, they effectively eliminate the common issues of friction noise and stiffness found in traditional composite membranes. This not only preserves the natural drape of the garment but also enhances wearing comfort, achieving a seamless protective effect [96,97]. This innovative design makes outdoor gear nearly indistinguishable in appearance from everyday fashion, blurring the line between professional sportswear and ordinary clothing. In urban application scenarios, the focus of nanofiber membrane development is not on pursuing maximum hydrostatic pressure performance but rather on achieving an optimal balance between rain protection and breathability. Using hydrophobic surface treatment technology inspired by the lotus leaf structure can effectively block rainwater penetration while promoting rapid sweat evaporation during air circulation [98]. This design is particularly suitable for addressing the heat and moisture regulation challenges faced by urban populations during activities such as cycling commutes or running workouts.

4.3.2. Smart Responsiveness and Multifunctional Integration for Diverse Scenarios

Due to the high complexity of urban environments and residents’ strong acceptance of new technologies, favorable conditions have been created for the promotion of responsive nanofiber membranes. Smart moisture regulation technology based on thermosensitive polymers, by grafting or compounding temperature-sensitive polymer materials into nanofibers, enables the development of adaptive breathable membranes. Under normal temperature conditions, the polymer chains remain in an extended state, keeping the membrane structure with open pores to ensure excellent moisture permeability. When exposed to high-temperature environments or during intense exercise that induces sweating, the polymer molecular conformation undergoes reversible changes—chain contraction leads to pore expansion, significantly accelerating the moisture transmission rate. This dynamic responsiveness ideally adapts to multi-scenario needs ranging from daily commuting to high-intensity exercise. Smart health monitoring clothing systems use flexible sensing elements made from conductive nanomaterials, which can be embedded in key areas of sportswear. These systems can continuously track the wearer’s vital signs such as heart rate and breathing rhythm, or provide active safety alerts during nighttime exercise using luminescent fibers [99]. By perfectly integrating the “detection-response” mechanism into the garment structure, such urban outdoor equipment has evolved into portable personal health monitoring terminals [100].

4.3.3. Unification of Esthetic Expression and Sustainability

Outdoor consumer groups with environmental awareness and esthetic preferences are becoming important application targets for nanofiber membrane technology [101]. In terms of color and texture design, nanofiber membranes exhibit high flexibility. This material can not only serve as a functional substrate but also combine with dyed fibers or incorporate color pastes, thereby achieving diverse and stable color presentations. By controlling fiber arrangement and stacking density, special optical effects and surface textures can be generated, opening up innovative aesthetic expression pathways for designers. As a key platform for practicing green development concepts, urban areas play a significant role in promoting environmentally friendly consumption patterns. The use of biodegradable raw materials in electrospinning technology to produce nanofiber films is attracting widespread academic attention. Such eco-friendly materials can decompose in specific environments after reaching the end of their service life, significantly reducing the potential for microplastic pollution. By replacing traditional toxic solvents with environmentally friendly solvents to produce nanofiber membranes, not only are sustainable industrial production standards met, but a perfect integration of high-tech outdoor apparel and eco-friendly concepts is also achieved.

4.4. Industry Standards and Standardization Process

The transition of nanofiber membranes from laboratory research to large-scale market applications relies on unified performance evaluation standards and industry regulations. In November 2025, China’s Ministry of Industry and Information Technology included “high-breathability electrostatic nanofiber composite materials for light outdoor protective clothing” in its key industrial chain advancement plan. One of its core tasks is to establish a targeted performance evaluation system and develop relevant standards. Although direct standards for nanofiber membranes used in outdoor clothing are still under development, existing standards from other fields can serve as references, such as the “Technical Requirements for Nanofiber Filter Materials for Air Filtration”. In the future, establishing a multidimensional standard system covering waterproof and moisture-permeable efficiency, durability, safety, and eco-labels will be crucial for guiding the healthy development of the industry, protecting consumer rights, and gaining market trust.

5. Challenges in Applying Nanofiber Membranes to Outdoor Sportswear

5.1. In-Depth Analysis of Scale-Up Production, Cost, and Performance Trade-Offs

The pathway to commercializing nanofiber membranes for outdoor apparel must be assessed against the entrenched position of conventional coating technologies. The latter benefits from decades of process optimization, supply chain maturity, and extremely high production speeds, resulting in low per-unit costs that are currently unmatched by nanofiber spinning processes. Although laboratory studies have demonstrated the excellent multifunctional properties of nanofiber membranes, numerous challenges remain in translating them into outdoor sportswear suitable for large-scale production. Traditional single-needle electrospinning yields approximately 0.1–1.0 g/h, while industrial-scale needleless or multi-needle systems can increase production to kilograms per day [102]. However, this is still far below the ton-per-day production speed of traditional melt-blown nonwovens. Air-jet spinning shows significant advantages in this regard, offering production rates an order of magnitude higher than electrospinning equipment of similar scale. It also eliminates the need for high-voltage power supplies, resulting in lower equipment investment and operational energy consumption. Centrifugal spinning similarly features high productivity, particularly suitable for producing fiber nonwovens with diameters in the micrometer range. Therefore, for high-end outdoor apparel pursuing extreme lightweighting and multifunctional integration, electrospun nanofiber membranes still hold irreplaceable value. However, for the mass market focused on basic protection and cost sensitivity, micro/nanofiber materials produced via air-jet or centrifugal spinning may represent a more pragmatic choice.

Cost analysis must encompass the entire lifecycle. Both direct material costs and indirect costs for electrospinning are relatively high. Taking DMF, a common laboratory solvent, as an example, its recovery and disposal costs cannot be ignored in large-scale production. “Green electrospinning” using water as a solvent is an important development direction. Research on water-soluble polymers like PVA and chitosan is relatively mature. However, for mainstream materials such as TPU and PVDF, water-based spinning still requires complex formulation modifications, which may affect the final membrane’s performance [103]. In contrast, air-jet spinning and centrifugal spinning have more lenient solvent requirements and can even employ direct melt spinning, fundamentally avoiding solvent costs and pollution issues.

The trade-off between performance and cost is the ultimate consideration in material selection. The comprehensive comparison in Table 2 and Table 3 indicates that electrospinning leads in fiber fineness, structural controllability, and functional integration. This is precisely the foundation for achieving high-end functions like high moisture permeability and intelligent responsiveness. For instance, electrospinning is currently almost the only viable laboratory preparation method for achieving Janus asymmetric wettability, precise PCM encapsulation, or constructing biomimetic hierarchical structures. While fiber membranes obtained via air-jet or centrifugal spinning may meet commercial standards for basic properties like moisture permeability and waterproofing, they have limitations in achieving complex structure-function integration. Therefore, future research should not be confined to optimizing a single technology. Instead, it should focus on clearly defining the performance upper limits and cost lower bounds achievable by different spinning technologies, and matching them according to the specific performance grades required for outdoor sportswear. Simultaneously, reducing the comprehensive cost of high-performance nanofiber membranes through process innovation and supply chain optimization is an essential path to promoting their industrialization.

5.2. High Production Costs

Nanofiber membranes are at a disadvantage in market competition with traditional high-end membranes due to their high production costs. These costs primarily stem from expensive high-voltage electrostatic equipment and precision fluid delivery systems, as well as the substantial electricity consumption required to maintain high-voltage electric fields and constant temperature and humidity production environments. In the field of fiber manufacturing, high-quality polymer raw materials are often costly. Particularly notable is the widespread use of organic solvents in research institutions, which not only pose toxicity and high costs but also significantly increase equipment investment and operational expenses in large-scale production through their recycling and disposal processes. Although aqueous solution spinning technology is considered an ideal alternative, there are few types of polymer materials suitable for this process that can produce high-performance separation membranes, often requiring complex formulation optimization. Furthermore, to enhance the mechanical properties and service life of the membranes, post-processing techniques such as hot pressing, chemical cross-linking, or substrate compositing are typically employed. These additional steps not only complicate the production process but also significantly increase overall production costs.

5.3. Challenges in Product Uniformity and Quality Control

Outdoor apparel requires large-area protective materials to maintain uniform performance. Scaling up laboratory processes for mass production presents significant challenges in ensuring consistent nanofiber membrane structure across the entire fabric. In wide-width production lines, maintaining uniform fiber construction is a major hurdle, with the key being to ensure even electric field distribution, consistent solvent evaporation rates, and stable fiber deposition across all areas. Even minor variations can lead to inconsistencies in fiber diameter, pore size, and membrane thickness, ultimately causing regional differences in waterproof and breathable performance and potentially creating weak points in garment functionality. During batch manufacturing, quality issues such as bead aggregation, fiber clumping, and pore defects are more likely to occur compared to laboratory conditions. These flaws can compromise the material’s waterproof properties and thereby affect the overall protective performance of the garment. To ensure the production system can operate stably for hours or even days without generating defects, strict control over equipment precision, environmental parameters, and raw material quality is essential.

6. Summary and Outlook

6.1. Summary

With ultra-large specific surface area, tunable pore structure parameters, and convenient functionalization characteristics, nanofiber membrane technology is driving the transformation of outdoor sportswear from passive protection to intelligent comfort experiences. This paper, taking “structural-functional collaborative design” as the starting point, comprehensively summarizes the latest research trends in this technology from fundamental preparation to multifunctional integration. This study systematically explores electrospinning as a key preparation method, pointing out that by precisely adjusting solution properties, processing parameters, and external environmental conditions, it is possible to accurately control fiber dimensions, alignment, and pore distribution. Subsequently, the paper elaborates on innovative structural design approaches such as multi-axial, porous/beaded, biomimetic, and composite structures, providing crucial support for developing multifunctional materials. This research focuses on the multifunctional integration of nanofiber membranes, conducting in-depth analysis of how structural optimization plays a key role in enhancing waterproof and breathable performance, achieving active/passive temperature control, strengthening durability and protective characteristics, developing smart sensing capabilities, and exploring environmental attributes. Addressing the performance requirements of diverse sports scenarios including extreme mountaineering, trail running, and urban outdoor activities, this study builds a bridge from material innovation to practical application, fully demonstrating the broad prospects of nanofiber membranes in scenario-adaptive design. This paper thoroughly discusses the main obstacles in the current industrialization process of this technology, particularly highlighting key issues in large-scale manufacturing such as efficiency and consistency, long-term reliability, and ecological friendliness with full lifecycle assessment Throughout the discussion, the contrast with conventional coating technologies—their strengths in cost and scale versus limitations in breathability and functional sophistication—serves to delineate the unique value proposition and current hurdles of nanofiber membranes. These challenges constitute the core constraints that require urgent solutions in subsequent scientific research and technological breakthroughs.

6.2. Future Outlook

The application of nanofiber membranes in the field of outdoor sportswear will develop towards the synergistic deepening of intelligence, customization, environmental sustainability, and industrialization It is unlikely that nanofiber membranes will completely replace conventional coatings in all market segments in the near term. Instead, a more probable scenario is market segmentation: conventional coatings will continue to dominate the cost-sensitive, basic protection segment, while nanofiber membranes will carve out niches in high-performance, premium, and smart apparel where their superior breathability, lightweight, and multifunctional integration offer compelling advantages. The future lies in leveraging the strengths of each technology, and potentially even exploring hybrid structures that combine the robustness of coatings with the advanced functionality of nanofibers. To achieve this vision, future research must continue existing technological trends while addressing core issues such as performance, mechanical reliability, cost-effectiveness, and scalability.

Integration of Intelligent Systems and Rational Cross-Scale Design. Cutting-edge technologies will drive outdoor apparel from passive protection to flexible intelligent platforms with environmental awareness, autonomous decision-making, and dynamic response capabilities. First, the deep integration of stimulus-responsive materials and microelectronic systems will form adaptive closed-loop control systems. For example, developing “living breathing” systems where membrane pores can intelligently open and close in real-time based on skin temperature and humidity. Second, leveraging digital twin and artificial intelligence methods to construct virtual simulation models that integrate personal physiological parameters, exercise status, and environmental factors, tailoring differentiated thermal and moisture management strategies for different users to achieve functional personalization. Finally, moving beyond traditional lamination processes to explore the in situ integration of functional modules such as energy harvesting, sensing, and display during the nanofiber manufacturing stage, building highly integrated fiber electronic systems [104].

Exploration of New Materials and Deep Integration of Biomimetic Principles. Beyond optimizing existing material systems, continuously exploring the application potential of novel nanomaterials such as MXenes, liquid metals, and covalent organic frameworks to break through bottlenecks in electrical conductivity, thermal conductivity, and mechanical properties. Simultaneously, biomimetic research should evolve from simple surface morphology replication to the principled emulation of sophisticated biological thermal and moisture management mechanisms. For example, mimicking the photothermal management structure of polar bear fur or the dynamic mass transfer mechanisms of mammalian subcutaneous vascular networks to construct multi-level, multi-scale biomimetic heat and mass transfer channels within nanofiber membranes, achieving more efficient and intelligent environmental adaptation [105].

Implementation of a Full Lifecycle Sustainable Development Philosophy. In the industrialization process, environmental sustainability concepts must be transformed from slogans into quantifiable and executable technical solutions. First, research and develop efficient biodegradable material systems (such as modified PLA, PHA) and truly environmentally friendly non-toxic/low-toxic solvent spinning processes. Second, optimize apparel design to facilitate disassembly and recycling, and vigorously develop efficient chemical recycling or physical reprocessing technologies to establish a closed-loop system of “resources-products-renewable resources.” Finally, conduct comprehensive Life Cycle Assessments (LCA) to quantify and compare the true environmental footprints of different technological pathways, providing data support for green decision-making [106].

Collaborative efforts in performance, cost, and scale for industrialization. To overcome the challenges of large-scale production and high costs, multi-objective collaborative optimization is essential. First, establish a database of mechanical properties and failure maps for nanofiber membranes. Through innovative cross-linking, composite, and finishing processes, enhance their wear resistance, tear resistance, and fatigue resistance to meet the stringent standards of commercial apparel. Second, develop a transparent cost model to clarify the trade-offs between performance improvements and cost increases, guiding the application of the technology to product areas where its added value is most evident. Finally, integrate the efforts of industry, academia, and research to jointly overcome bottlenecks in manufacturing equipment for high throughput, low energy consumption, and high uniformity. This will advance processes such as electrospinning from the laboratory to production lines and objectively evaluate the scalability advantages of alternative technologies like air-jet spinning in specific scenarios [107].

In summary, future research must break down the disciplinary barriers between materials science, electronic engineering, biomechanics, environmental science, and industrial manufacturing. Through deep cross-disciplinary collaboration, the focus should not only be on achieving “intelligent” functionality but also on ensuring the “durability,” “affordability,” and “sustainability” of the products. Only in this way can nanofiber membrane technology evolve from exceptional laboratory samples into the next generation of personalized intelligent protection systems, trusted and utilized by a wide range of outdoor enthusiasts.