Search Results (517)

Coatings based on polyvinylidene fluoride (PVDF) and poly(dimethylsiloxane) (PDMS)-based polymeric microspheres can be easily fabricated via non-solvent-induced phase separation (NIPS) and electrostatic spraying (ES) techniques. Both techniques are promising strategies for constructing superhydrophobic surfaces on various substrates. However, PVDF and PDMS inherently suffer from severe aggregation, which generates oversized particles and inhomogeneous microstructures. Conventionally, costly and environmentally hazardous dispersants are required to alleviate this issue, severely restricting the industrial scalability and practical application of such coatings. In this work, methyltrimethoxysilane-modified cellulose nanocrystals (Si-CNCs) were introduced as a green multifunctional modifier to tackle these issues. The results revealed that as structural building blocks and dispersants, Si-CNCs inhibited polymer aggregation via electrostatic repulsion and steric hindrance, refined the particle size and formed uniform micro/nano hierarchical structures. Increasing Si-CNC loading further improved polymer dispersion and superhydrophobic performance. Coatings fabricated by ES showed better hydrophobicity than those fabricated by NIPS. ES achieved a water contact angle (WCA) of 160–166° and a sliding angle (SA) near 1° on cotton fabric, while NIPS had a WCA of 153.8–158° and an SA of around 2°. Wood and glass substrates also obtained favorable superhydrophobicity, with WCAs above 150° and SAs below 1°. Furthermore, all modified surfaces exhibited excellent abrasion resistance. This work provides a relatively eco-friendly, environmentally sustainable, scalable and substrate-flexible strategy for fabricating high-performance PVDF/PDMS-based superhydrophobic coatings. Full article

In the present work, polyvinylpyrrolidone (PVP) was selected as the primary raw material and fully dissolved in N,N-dimethylformamide (DMF) solvent. Hydroxymethyl cellulose (HMC), acrylic acid (AA) monomer with outstanding chelating performance, and UR were added in sequence. On this basis, composite nanofiber membrane substrates of PVP/AA/HMC/UR were fabricated by means of electrospinning. Afterwards, silane coupling agent KH-560 was blended with polylactic acid (PLA). A uniform PLA/KH-560 functional coating was covered on the surface of the as-prepared nanofiber membrane via microfluidic coating treatment, and the target composite nanofiber adsorbent was ultimately obtained. Relevant performance characterization results indicated that moderate addition of HMC could greatly optimize the tensile strength of the membrane material, whereas excessive HMC dosage would cause a deterioration in mechanical strength. Moreover, the breaking elongation presented a slight declining trend, and the integrated mechanical stability of the membrane could fully meet the service demands for cyclic reuse. As a functional monomer, acrylic acid effectively boosted the material’s adsorption performance toward typical heavy metal ions, including Zn²⁺, Cu²⁺ and Pb²⁺. In simulated acidic wastewater generated from rare earth mining and extraction (pH = 3 and pH = 6.5), the removal efficiency of the as-prepared material for the three heavy metal ions all exceeded 95%. Even after being soaked in strong acid solution at pH 2 for 8 h, its adsorption rate was still maintained at 88.5%. In the cyclic experiment, the adsorption efficiency stayed above 75% after two recycling runs, decreased to roughly 55% in the third cycle, and dropped below 30% at the fourth reuse stage. The introduction of UR imparted remarkable acid-resistant structural stability to the composite material. The membrane structure remained complete without damage after long-term immersion in a pH 2 strong acid environment, and high-efficiency heavy metal removal capability could be guaranteed when the solution pH was not lower than 3. Targeting the practical treatment dilemma of acidic heavy metal-containing wastewater from rare earth exploitation and extraction, this research successfully developed a novel eco-friendly adsorbent featuring superior acid resistance, high adsorption performance and certain recyclability. This newly designed material makes up for the deficiencies in traditional adsorbents represented by activated carbon, including poor heavy metal removal ability in acidic media and secondary pollution risks resulting from disposable use. The research findings can offer a novel technical reference and feasible approach for the purification of acidic rare earth wastewater in practical engineering applications. Full article

Hollow fiber loose nanofiltration (HF-LNF) has attracted increasing attention as a pressure-driven membrane platform that combines loose nanofiltration (LNF) selectivity with the high packing density and self-supporting geometry of hollow fibers. This review critically evaluates recent advances in HF-LNF membranes, including controllable fabrication strategies, surface functionalization techniques, and practical engineering applications, with a discussion of life cycle assessment (LCA) for evaluating the environmental and economic sustainability of HF membrane systems. Phase inversion, interfacial polymerization (IP), coating, and grafting are compared in terms of structural controllability, process complexity, selective-layer stability, modification uniformity, reproducibility, and scale-up feasibility. Phase inversion is relatively compatible with continuous hollow-fiber spinning, but independent regulation of the support and selective layer remains difficult. IP provides greater control over selective-layer chemistry and effective pore size, whereas coating and grafting offer flexible surface functionalization but may be limited by additional transport resistance, layer durability, and non-uniform modification of curved surfaces. Direct HF-LNF application remains concentrated on dye/salt separation. Based on the evidence from HF-NF or flat LNF systems, the potential of HF-LNF in water softening, heavy metal removal and emerging pollutant control is analyzed. Critical challenges restricting industrial translation are discussed, including poor long-term antifouling capacity and difficulties in large-scale, low-cost manufacturing. On this basis, LCA is further introduced as a decision-support framework for identifying potential environmental hotspots in membrane manufacturing and operation, while the limited availability and comparability of HF-LNF-specific life-cycle data are explicitly recognized. Ultimately, it is proposed to focus on novel functional materials, eco-friendly preparation processes, and scaled membrane engineering, aiming to offer theoretical support for the rational design and real-world industrial deployment of next-generation HF-LNF membranes. Full article

In this study, a two-step electrodeposition strategy was proposed to fabricate an eco-friendly superhydrophobic polyaniline (PANI)/silane composite coating on mild steel for corrosion protection. The first step consists of creating a pure PANI adherent coating using a cyclic voltammetry technique and the second step consists of realizing superhydrophobic features using electrodeposition in mixed silane monomers at constant potential. The structure and composition characterization results revealed successful modification of the underlying pure PANI layer with superhydrophobic surface silane film. Wettability tests indicated a high contact angle of 155° and a low sliding angle of 4.2°. Electrochemical measurements revealed that the corrosion current density of PANI/silane-coated mild steel decreased by approximately three orders of magnitude compared to the uncoated sample and the corrosion protection efficiency was as high as 99.6%. Moreover, the prepared PANI/silane hybrid coating exhibited good chemical stability and strong adhesion after 10 days of corrosion in 3.5 wt.% NaCl solution. Full article

The corrosion-protection performance of zinc oxide-hybrid polymeric coatings is traditionally attributed to the individual contributions of their constituent phases. This study reveals that the calcination temperature of zinc oxide (ZnO) filler is a critical, previously overlooked processing parameter that dictates not only filler crystallinity but also the collective synergistic failure mechanism of the entire coating system. Herein, we demonstrate that incorporating ZnO calcined at 500 °C yields a ternary chitosan–graphene oxide–zinc oxide/epoxy (CS–GO–ZnO/EP) composite coating with a highly compact, dense morphology, minimal internal porosity, and exceptional filler dispersion, as validated by FTIR, XRD, and SEM analyses. The optimized CS–GO–ZnO/EP coating applied to carbon steel exhibits outstanding dry and wet pull-off adhesion strengths, the highest surface hydrophobicity (102.2°), and superior electrochemical barrier protection. Notably, after a 120-h immersion period in an aggressive 3.5 wt.% NaCl electrolyte, the CS–GO–ZnO/EP (500 °C) maintains excellent coating resistance (R_coat = 1.06 × 10⁵ Ω) and a minimized corrosion rate (CR = 0.074 mm/y). This thermal threshold is a key processing window that improves chemical bonding and compatibility between the different parts of the hybrid matrix without causing the severe nanoparticle sintering, phase aggregation, and micro-cracking that happen at 650 °C. This work offers a significant advancement in the design of eco-friendly, high-performance hybrid coatings, demonstrating that precise control of the inorganic phase’s thermal history provides a direct pathway toward superior durability, hydrophobicity, and electrochemical stability for carbon steel protection in aggressive marine environments. Full article

The surface modification of polyolefin separators for lithium-ion batteries using polymer particles has been extensively investigated to enhance their electrolyte wettability, thermal resistance, and mechanical properties. However, the traditional polymer synthesis and/or polymer-based separator modifications have mostly been carried out using harmful and expensive organic solvents. In this study, a powder-type polyimide (PI) was synthesized using water as a solvent, and then PI-particle-containing coating slurries were prepared in an aqueous dispersion medium. The coating slurries were applied on a polyethylene (PE) separator to obtain PI-particle-coated PE (PI-PE) separators. Thermal and mechanical properties were evaluated for the PI-PE separators. Electrolyte uptake, porosity, air permeability, and ionic conductivity of the separators were also evaluated. The electrochemical properties of coin cells assembled with the PI-PE separator were evaluated by charge–discharge property. Coating of PI particles improves the thermal stability and electrolyte wettability of the PE separator, and LiCoO₂/PI-PE separator/Li half-cells showed battery performance similar to that of bare PE half-cells. This work offers insights into the simple, eco-friendly preparation of a separator with excellent thermal stability, electrolyte wettability and effective ionic conductivity. Full article

Methods for extracting bioactive compounds are widely studied, as the global trend moves toward more efficient and eco-friendly methods. This study aimed to optimize and compare the extraction of phenolic compounds from the residual biomass of andiroba (Carapa guianensis) using the conventional method with methanol as the solvent, and a green chemistry method via ultrasound using ethanol as the solvent. The optimization of the extraction variables (time, mass/volume ratio, and ethanol concentration) was performed using a Central Composite Rotatable Design (CCRD 2³) combined with the desirability function. The established optimal conditions were an extraction time of 26.78 min, a mass/volume ratio of 86.46 mg/mL, and an ethanol concentration of 32.5%. The conventional method achieved a higher yield of total phenolic compounds (TPC) (109.05 mg GAE/mL) and total flavonoid compounds (TFC) (38.18 mg GAE/mL) compared to the ultrasound-assisted method (UAE) (82.64 and 26.27 mg GAE/mL, respectively). LC-MS analysis revealed a diversity of extracted bioactive molecules. Both methodologies yielded extracts with good in vitro antioxidant activity (DPPH and ABTS). In the antimicrobial assay, the extracts demonstrated an unprecedented bacteriostatic effect for this residue, inhibiting the growth of the Gram-positive bacterium Staphylococcus aureus at concentrations ranging from 43.83% to 52.67%, with no activity against Gram-negative bacteria. The optimization demonstrated that the industrial residue of andiroba still contains a significant concentration of bioactive compounds. These findings confirm the bioeconomic potential of this by-product for the formulation of high-value-added bio-inputs, with promising applications in the development of smart packaging or bioactive food coatings. Full article

Tribology is a growing field concerning reductions in the environmental footprint of tribological systems while increasing their operational efficiency by minimizing friction, wear and lubrication in an environmentally conscious manner. This review aims to discuss in detail sustainable lubrication strategies, with particular emphasis on surface modification and coating-based strategies for advanced tribological applications. The surface engineering techniques covered in this study are critically reviewed with regard to their ability to improve wear resistance, reduce friction and increase the durability of components, such as laser surface texturing (LST), nitriding, plasma treatment and advanced coating technologies such as DLC-, TiN-, CrN- and PVD-based coatings. Another key focus is on the synergy of sustainable lubricants and engineered surface coatings. The tribochemical compatibility of eco-friendly lubricants, bio-lubricants, ionic liquids and advanced coated surfaces is explained in detail, because they are essential for the formation of stable tribofilms, lubricant retention, reductions in surface degradation, and the minimization of tribological losses. They are an important component of environmental footprint, energy consumption and the thermal stability and service life of tribological components. Recent developments in coating-assisted green tribology, sustainable tribochemistry and circular sustainability concepts of the design of tribological systems are also included in the review. In addition, the review briefly outlines the use of Life Cycle Assessment (LCA) as a potential tool for the future evaluation of the environmental sustainability of tribological systems. The proposed expanded set of Green Tribology principles offers useful guidance for the implementation of tribology-based solutions toward more sustainable engineering systems and responsible resource utilization. Full article

Developing durable multifunctional clothing with enhanced mechanical and comfort properties utilizing eco-friendly, cost-effective hybrid nano finishes is highly challenging. The reason behind the nondurable functionality is the lack of bonding ability of nanoparticles (NPs) with cotton fabric, and this additional coating has a great impact on the mechanical, thermo-physiological, and sensorial comfort properties of cotton fabric. Focusing on these issues, this paper attempts to develop biogenic chitosan-loaded CuO-SiO₂ hybrid nano finishes with three distinct formulations, namely Chi-CuO-SiO_2(5g/L), Chi-CuO-SiO_2(10g/L), and Chi-CuO-SiO_2(20g/L) hybrid nanofluids, to incorporate on cotton fabric by pad-dry-cure method. These hybrid nanofluids from biogenic Chi-CuO and rice husk SiO₂ NPs have been newly introduced for textile application. The NPs CuO and SiO₂ are synthesized from lemon peel zest extract and rice husk, respectively. Characterization of CuO NPs by Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive Spectroscopy (EDX), and X-ray diffractometers (XRD) evidences that spherical-shaped, amorphous, and 60–80 nm sized NPs are synthesized. The hydrodynamic performance of hybrid nanofluids measured by Zeta Sizer shows that the chitosan-loaded CuO-SiO_2(5g/L) hybrid nanofluid is the most stable among the three, and the value is +29.4 mV. The presence of CuO NPs, SiO₂ NPs, and chitosan on cotton fabric was confirmed by FTIR, FESEM, and EDX spectra of the hybrid nanofluid-deposited fabric. The cotton fabric coated with chitosan-loaded CuO-SiO₂ hybrid nanofluids exhibits better durable antimicrobial efficacy, UV-protective properties, and thermo-physiological comfort properties than that of the uncoated fabric. More specifically, CuO-SiO_2(20g/L)-coated fabric demonstrates approximately 99.99% bacterial efficacy against both gram-positive and gram-negative bacteria even after 15 washing cycles, and excellent UV-protective properties. In addition, CuO-SiO_2(5g/L)-coated fabric displays around 75% enhancement of overall moisture management properties and 1.22% and 0.53% enhancement of tensile strength in warp and weft directions with excellent elongation compared to the pristine one. Moreover, assessment of the mechanical sensorial comfort properties of this fabric depicts that it is smoother, and has better thermal conductivity than that of the control one. In addition, CuO-SiO_2(5g/L) hybrid nanofluid-treated cotton fabric exhibited cell viability above 95%, which confirms its non-cytotoxicity. The outcomes of this study suggest that chitosan-loaded CuO-SiO_2(5g/L) hybrid nanofluid-treated cotton fabric can be considered as optimum and employed as biomedical textiles with better mechanical and comfort properties. Full article

This study aimed to determine the effects of whey protein isolate (WPI)-based edible gel coatings, enriched with different additives, on the quality parameters of strawberries (Fragaria x ananassa). The coating solutions were prepared in five different formulations: control (uncoated), WPI-based gel coating (GC), WPI + magnesium powder (GCMg), WPI + cinnamon essential oil (GCEo), and WPI + magnesium + cinnamon essential oil (GCMgEo). In the study, each experimental group was stored at 4 °C for 21 days and evaluated in terms of color parameters (L*, a*, b*, C*, h°, ∆E), weight loss, pH, Water soluble dry matter (WSDM), moisture content, redox potential (Eh), adhesion rate of the coating, decay percentage, texture analysis, and sensory properties. The results revealed that the GCMgEo group yielded the most successful outcomes in terms of color stability, oxidative resistance, and microbial control. However, sensory evaluation scores in this group were found to be lower compared to other groups. The highest overall acceptability scores were observed in the control group up to the 14th day. The coating applications were found to preserve the firmness and integrity of the strawberries, while the adhesion percentage increased with certain additives. Moreover, WPI-based coatings formed a protective film on the fruit surface, providing protection against compression and mechanical damage. These results indicate that while edible coatings slow down the ripening process, some additives may have negative effects on aroma and taste. As a result, WPI-based edible gel coatings have the potential to extend the shelf life of strawberries and reduce quality losses. The addition of magnesium and cinnamon essential oil enhances the functional performance of the coatings but requires sensory optimization. This study reveals that naturally derived coating systems can offer an eco-friendly and effective alternative for preserving fresh fruits. Full article

Intumescent coatings are widely used to enhance the fire resistance of structural steel. In contrast to traditional fire protection methods, this novel flexible intumescent protection offers several key advantages: universal compatibility with other coatings (via non-contact wrapping), resistance to extreme temperatures (−60 °C to +90 °C), all-weather usability, and suitability for light-gauge cold-formed thin-walled steel structures. This paper describes the development and investigation of these fire-protective, flexible intumescent coatings based on eco-friendly binders (silicone polymers and acrylic resins) with varying intercalated graphite (IG) content from 0% to 40%. An IG content of 25–40% enables a steel I-section with a section factor of 294 mm⁻¹ to reach its limit state at 44 min (compared to 15 min for unprotected steel). Fire tests on steel beams with a section factor of 172 mm⁻¹ demonstrated that samples reached the deflection limit state at the 64th and 66th minutes, respectively. Thermogravimetric analysis (TGA) was used to determine the temperature ranges for the thermal decomposition and expansion of the IG. Mechanical property studies revealed the influence of IG on the elastic modulus and tensile strength. Accelerated climatic testing in moderately cold conditions and salt spray chamber tests confirmed that the intumescent roll coating has no negative impact on the steel substrates. Full article

The development of sustainable and functional surface coatings has become a central theme in materials science due to increasing environmental concerns and expanding biomedical needs. This study reports the preparation and characterization of bio-based polylactic acid (PLA) nanofibrous coatings fabricated by electrospinning, aimed at delivering biodegradable and bioactive surfaces with controlled release functionality. Electrospinning enabled the formation of uniform nanofibrous coatings with high surface area and morphology reminiscent of extracellular matrices, presenting potential as multifunctional coating platforms. The obtained coatings were systematically evaluated for their physicochemical and biological properties, including antioxidant activity, cytocompatibility, and the controlled release of acetylsalicylic acid as a model bioactive agent. Release behavior was analyzed to elucidate the dominant transport mechanisms, revealing a biphasic profile characterized by an initial burst followed by sustained diffusion-controlled release. These results demonstrate that the electrospun PLA coatings successfully combine biodegradability, bioactivity, and tunable release properties within a bio-based polymer coating format. The findings highlight the potential of such bio-based polymer coatings for biomedical applications where biodegradable and functional surface solutions are required, and contribute to the broader advancement of eco-friendly and multifunctional coating technologies. Full article

This study investigates the biogenic synthesis of copper oxide nanoparticles (CuO NPs) using the aqueous extract of pistachio seed coat as a stabilizing and reducing agent, and a better alternative to the traditional physicochemical approach. The CuO NPs were synthesized by a sustainable approach and characterized using XRD, UV–visible, FTIR, FESEM-EDX, and HRTEM-SAED, and are emphasized for their significance in comprehending how morphology, size, and surface chemistry affect the performance of CuO NPs. The UV–visible spectrophotometry showed an absorption at 273 nm, demonstrating the formation of CuO NPs. SEM and TEM provided a spherical shape with a size range of 50–100 nm. CuO NPs’ antifungal activity was examined against the fungal strains A. niger and P. chrysogenum, and their antibacterial efficacy was evaluated using the agar well disc diffusion method against E. coli and S. aureus. Staphylococcus aureus had the largest inhibitory zone, measuring 18 mm at 100 µg/mL, while Aspergillus niger had the smallest, measuring 8 mm at 25 mg. The IC₅₀ value of the sample was 319.55 ± 3.21 µg/mL. The IC₅₀ value indicates that the CuO NPs exhibit moderate antioxidant potential. The synthesized CuO NPs exhibited excellent catalytic efficiency in the cyclization reaction of chalcones. The findings of the present study highlight CuO NPs synthesis by an eco-friendly, cost-effective and sustainable method from pistachio shell extract. The synthesized CuO NPs demonstrated notable biological and catalytic activity that underscores their future need in various fields such as pharmaceutical, biomedical and industrial catalysis. Full article

Loquat is a highly perishable, non-climacteric fruit that is prone to chilling injury, decay, and eating quality deterioration during cold storage. This study evaluates the effectiveness of tragacanth gum (TG) as a plant-based edible coating to mitigate postharvest chilling injury (CI) and preserve the eating quality of loquat fruit. Two commercial cultivars, ‘Sufaid’ and ‘Surkh’, were coated with 1% TG and stored at 4 ± 1 °C with 90 ± 5% relative humidity for 20 days, followed by 2 days at 20 °C ± 1 °C (specific focus on retail handling). TG-coated fruits exhibited significantly reduced weight loss and lower decay compared to controls. TG application alleviated CI symptoms and reduced respiration rates. TG-treated fruits maintained higher levels of titratable acidity, total soluble solids, and ascorbic acid. TG application also elevated phytochemical levels and antioxidant potential, reinforcing the fruit’s biochemical defenses against postharvest stress. Furthermore, TG treatment suppressed oxidative stress by lowering malondialdehyde and hydrogen peroxide levels and enhanced the activities of key antioxidant enzymes (SOD, CAT and APX). TG-coated fruits also showed improved taste, flavor, and consumer acceptability at shelf after storage. In conclusion, results indicate that application of TG coating represents a sustainable, eco-friendly strategy to alleviate CI and improve postharvest eating quality of commercial loquat cultivars, offering potential for broader adoption in the fresh fruit supply chain. Full article

In this study, an ecofriendly microfluidic microbial biocathode electrolysis cell is developed for hydrogen production. Low-cost microbial catalysts are employed on single-walled carbon nanotube cathodes instead of noble metal (platinum) catalysts. The channel layer for the electrolyte flow is fabricated from polydimethylsiloxane and coated with Parylene C to minimize oxygen permeability. A miniaturized electrolysis cell is constructed by depositing electrodes onto a glass substrate and bonding them to a polydimethylsiloxane channel layer via plasma surface treatment. The establishment of the biocathode during the start-up procedure is analyzed, and the hydrogen production performance of the biocathode microbial electrolysis cell (MEC) is evaluated under various applied voltages and electrolyte flow rates. At higher applied voltages and optimal flow rates, biofilm formation is well-developed, resulting in a peak hydrogen production rate of 14.8 m³ H₂ m⁻³ d⁻¹. The developed MEC biocathode demonstrates significant performance, achieving a current density of 0.22 A m⁻², corresponding to 69% of that of a platinum-catalyzed cathode MEC, while exhibiting a substantially longer operating duration of 12 h. These results demonstrate the potential to overcome the inherent limitations of biocathodes, thereby addressing the high cost and low durability of conventional platinum-catalyzed MECs. Compared with conventional MEC systems, the proposed microfluidic configuration enables membraneless operation with reduced internal resistance and rapid biofilm formation, demonstrating its potential as a compact and cost-effective platform for biohydrogen production. Full article