Editorial Insight on Special Issue “Recent Developments on Functional Coatings for Industrial Applications, Volume II”

The topic of functional coating technology has seen an increasing interest in recent years, driven by the promising perspective to enhance engineered materials. While coatings have traditionally served the fundamental purposes of environmental protection or esthetics, the modern industrial field now demands multifunctional and smart coatings for several complementary applications [1,2,3]. This growing need has favored the development of innovative, high-performance coatings designed to provide targeted capabilities [4,5,6,7]. These capabilities are relevant, ranging from high durability in severe environmental conditions [8,9,10] and chemo-, mechanical-, and thermal stability [11,12] to tailored surface textures, preserving performance and environmental sustainability [13,14].

The aim of this Special Issue (SI) is to further contribute to the improvement of knowledge regarding the synthesis, characterization, and tailoring of functional coatings, emphasizing their emerging industrial applicability across several sectors. The 10 research papers included here collectively delve into the design, tailoring, and optimization of these critical materials, focusing on both fundamental synthesis and industrial scalability. The variety of deposition techniques and material systems explored herein confirms the interdisciplinary nature of this field. This SI serves as a further resource, reinforcing the applicative importance of tailored functional surfaces in maximizing component lifetime, reducing maintenance costs, and ensuring operational reliability.

The research articles in this SI have been grouped by their core focus, showcasing concentrated efforts in three areas of industrial coating application: (a) Corrosion and Durability, (b) Anti- and De-Icing Technologies for Wind Turbines, and (c) Wear and Specialized Surface Functionality.

(a)

Corrosion and Durability

Coatings designed for aggressive chemical environments and cathodic protection are important for components and structures. This collection features two papers that delve into this theme, focusing on material stability and interfacial integrity.

Pélissier et al. [15] investigated the long-term performance of fusion bonded epoxy (FBE) and liquid epoxy (LE) coatings under the highly alkaline environment generated by cathodic protection (CP) on buried steel structures. They found that while FBE remained stable, the specific LE formulation suffered significant degradation and interfacial failure, underscoring the critical need to validate coating compatibility with CP-induced alkalinity during specification.

Complementing this macro-scale protection research, Lazauskas et al. [16] examined SiOx-doped DLC films for micro-scale precision engineering, showing that the ion-beam-synthesized coating offers superior, long-term corrosion resistance for raster steel linear scales.

(b)

Anti- and De-Icing Technologies for Wind Turbines

Many papers in this Special Issue (five in total) focus on the extensive and costly problem of ice accumulation on wind turbine blades, particularly in freezing and offshore environments. Several studies explored the fundamental icing characteristics of wind turbine airfoils, and their authors established how environmental and geometric factors influence ice formation, which is crucial for design and maintenance. Specifically, the authors of [17] utilized wind tunnel tests and structural analysis to quantify how conditions like wind speed, temperature, and liquid water content increase ice accumulation at the leading edge and subsequently negatively impact the blade’s mechanical properties. Focusing on offshore turbine airfoils, the authors of [18] found that the blade icing area and growth rate increase with greater chord length and angle of attack, providing key scaling insights. Furthermore, in [19] a numerical simulation confirmed that the peak ice thickness is more significantly affected by the Angle of Attack (AOA) than by ambient temperature, offering valuable data for developing effective anti- and de-icing technologies.

Finally, some related studies addressed practical solutions: in particular, the authors of [20] investigated electro-thermal de-icing via wind tunnel tests, identifying four de-icing patterns and determining optimal heat fluxes (e.g., 10 kW/m² at 5 m/s) to minimize energy and prevent refreezing. Furthermore, the authors of [21] complemented this with a novel anti-deicing spray method, using computational fluid dynamics to optimize application parameters (like angle of attack and nozzle flow rate) to maximize liquid film coverage.

(c)

Wear and Specialized Surface Functionality

The final articles cover specialized industrial demands, addressing disparate yet relevant industrial research fields. In the area of advanced manufacturing and tool longevity, Bouzakis et al. [22] provided a mechanistic look at wear evolution in PVD-coated cutting tools. This in-depth analysis introduced experimental procedures to explain coating fatigue failure and conclusively showed that increasing the strain rate significantly reduces tool life by diminishing the coating’s ability to resist fatigue-critical strains, an important finding for predicting performance in dynamic cutting operations. Shifting focus to safety and protective textiles, Zhao et al. [23] successfully addressed the need for superior chemical resistance. The researchers fabricated a waterproof and breathable superhydrophobic and acid–alkali-resistant polyester fabric. This was achieved using plasma processing combined with PDMS and PTFE powders, ultimately yielding a practical solution for enhancing staff safety in environments involving hazardous chemicals. Lastly, Sico et al. [24] focused on environmental technology with a focus on oil spill mitigation. The researchers developed novel hydrophilic and oleophobic TiO₂ coatings on 304 stainless-steel mesh filters via a multi-phase deposition method. They achieved remarkably high oil retention efficiency, up to 99%, thus offering promising, efficient, and affordable technology for large-scale oil/water separation.

Collectively, these articles confirm that the most fruitful path forward is the multidisciplinary approach. Surface engineering requires a synergistic integration of materials chemistry, process control from mechanical engineering, and well-defined performance validation for industrial applications. All papers in this Special Issue highlight the comprehensive approach needed to advance the field. By detailing novel synthesis routes, proposing characterization approaches, and validating relevance using industrial application data, the authors supported the improvement of knowledge to tailor and adapt functional coatings. The insights shared in this Special Issue are expected to stimulate further exploration and practical application of functional coating and surface engineering, supporting the ongoing activities toward improved industrial performances.