High Water Contact Angle Research Articles

Coating technology on mortar surface for extending service life of on-site building construction

The superhydrophobic, self-cleaning and anti-corrosion surface was successfully coated on mortar using an effective one-step spray coating technique. A coating solution was prepared by mixing methyltrichlorosilane-modified SiO2/TiO2 nanoparticles at different ratios to enhance the super-hydrophobicity and reduce water absorption of the mortar. The sample prepared using a SiO2/TiO2 with the ratio of 75/25 was found to be optimal, exhibiting a high water contact angle and low sliding angle, which resulted in a reduction of water absorption more than 97.5 % and chloride ion penetration depth. Furthermore, the robustness of the superhydrophobic coating was analyzed against various tests including water drop impact, sand abrasion impact, tape peeling and sandpaper abrasion tests, with each test conducted over 10000 drops, 300 g, 60 cycles, and 5 cycles, respectively. Notably, the coating showed excellent water absorption reduction of 82.6 % after sandpaper abrasion for a length of 200 cm (20 cycles), even though the water contact angle was reduced to 118?. Thus, the fabrication of superhydrophobic mortar surface offers a novel, alternative approach that is simple, efficient, cost-effective and provides multifunction protection surface to increase the service life of on-site building construction with enhanced mechanical durability and anti-corrosion properties.

Flexible wearable piezoresistive physical sensors with photothermal conversion and self-cleaning functions for human motion monitoring.

Flexible wearable sensors can mimic the sensing ability of the skin and transform deformation stimuli into monitorable electrical signals, making them favorable in the fields of personalized healthcare, human motion monitoring, and remote monitoring systems. Here, an innovative piezoresistive physical sensor based on fluorine-free superhydrophobic dodecyltrimethoxysilane/polypyrrole/carbon nanotube (DTMS/PPy/CNT) cotton fabrics (DPC-CFs) was assembled via an environmentally safe and simple dip-coating method. The flexible wearable sensor exhibits self-cleaning capability (high water contact angle of 158.3°), good electrical conductivity (45.43 S m-1), photo-thermal conversion (surface temperature up to 94.8 °C), rapid response/recovery time (60 ms/50 ms), and excellent stability (>2400 cycles), and was successfully applied to dynamic monitoring of a series of human activities such as wrist pulse, voice recognition, and finger bending. Furthermore, the development of the superhydrophobic piezoresistive physical sensor derived from biodegradable cotton fabrics means an important step forward in the evolution of wearable sensors, which not only provide better coverage of three-dimensional irregular surfaces to capture mechanical stimulation signals but also demonstrate better comfort, flexibility and versatility. It is foreseen that such sensors, which are fabricated by utilizing abundant renewable and biodegradable green raw materials, have a broad application prospect in the next generation of biomedical systems, fitness, and human-computer interactive devices.

Superhydrophobic nanofiber membranes with 3D-network reinforced pore structure for membrane distillation

Electrospun nanofiber membranes (ENMs) have garnered significant attention among researchers for membrane distillation (MD) in treating high-salinity wastewater due to their high water flux and low mass transfer resistance. However, a significant challenge in using ENMs for MD is membrane wetting, which results from the deformation of their weakly randomly overlaid nanofibers structure due to water flow shear forces. Herein, we focused on the membrane's structure and successfully prepared superhydrophobic nanofiber membranes with 3D-network reinforced pore structure by immersing PVDF ENMs in a mixed solution of polydimethylsiloxane (PDMS) and titanium dioxide nanoparticles (TNPs) after a hot-pressing treatment for impregnation and coating. The resulting membrane exhibits exceptional properties, including a high water contact angle (WCA) of 160.3°, a high liquid entry pressure (LEP) of 1.57 bar, and sustained structural integrity with an unchanged pore size distribution even after 5 h of water scouring. These characteristics contribute to a water flux of 39.3 kg·m−2·h−1 and an unexpectedly long durability of up to 102 h, along with an outstanding salt rejection exceeding 99.99 %. Moreover, the membrane demonstrates stable water flux and resistance to wetting when processing a 3.5 wt% NaCl solution containing 0.1 mM sodium dodecyl sulfate (SDS), underscoring its significant potential for MD applications.

Development of PDMS/TiO2/Ag3PO4 antibacterial coating on 316L/PDMS implants: Evaluation of superhydrophobicity, bio-corrosion, mechanical behaviour, surface nanostructure and chemistry

Nanocomposite coatings based on polydimethylsiloxane were developed by adding silver phosphate and titania nanoparticles with a PDMS pre-layer for 316L stainless steel. FTIR spectra and XRD patterns confirmed the synthesis of TiO2 and Ag3PO4 nanoparticles and nanocomposite coating. FESM and AFM images show that with the increase of Ag3PO4 nanoparticles, the roughness of coatings increased (Ra and Rq for adding 7 wt% of Ag3PO4 coating was 29 and 293 nm). The wettability results demonstrated that the presence of 7 wt% Ag3PO4 nanoparticles in the coating has the highest water contact angle (152 °). Nano-scratch results proved that creating a pre-layer of PDMS can increase the scratch resistance of PDMS + TiO2+Ag3PO4 nanocomposite coating (displacement and scratch coefficient were 408 nm and 0.07μΝ−1/2 with the pre-layer). Corrosion current density of 316lSS with PDMS + TiO2+Ag3PO4 coating was 0.00045 μA/cm2, while for 316LSS with pure PDMS coating was 0.00114 μA/cm2 at 37 °C in PBS solution. The Nyquist curves showed the diameter of the semicircle for the nanocomposite coating was larger than pure PDMS coating, which indicates the higher corrosion resistance of the nanocomposite coating (5.98 × 107 Ω). By increasing Ag3PO4 nanoparticles from 1 to 7 wt%, the number of E. coli bacteria in contact with the nanocomposite decreased significantly from 580000 to 31000 CFU/cm2. In the disk diffusion test, the largest inhibition zone was related to the nanocomposite coating with the addition of 7 wt% Ag3PO4 (23 mm). Therefore, the PDMS + TiO2+Ag3PO4 nanocomposite coating has improved properties such as superhydrophobicity, advanced mechanical behavior, bio-corrosion resistance, and antibacterial activity.

Effect of Ultrasonic Cleaning after Laser Texturizing of Surface of AISI 316L Steel on the Degree of Wetting and Corrosion Resistance

One of the most common current processing methods in various scientific studies is the modification of surfaces of various structural materials via laser radiation (laser ablation technique). The laser texturizing of metal surfaces is one of the promising applications for the creation of hydrophobic surfaces with a high water contact angle, increased corrosion resistance, and other properties. This paper reports the results of experimental studies to determine the effect of ultrasonic surface cleaning after laser texturizing on the degree of wetting and corrosion resistance of AISI 316L steel. The results show that ultrasonic cleaning leads to the removal of micro-/nano-sized particles formed on the surface following the laser texturizing of roughness. This effect, in turn, helps us to obtain higher values for the water contact angle and to increase the corrosion resistance.

One-pot coatable fluorinated polyurethane resin solution for robust superhydrophobic anti-fouling surface

Superhydrophobic coating materials have considerable potential in a wide range of industrial applications because of their anti-fouling properties. However, their application is limited due to the instability caused by their fragile structure, resulting in superhydrophobic failure. Moreover, achieving superhydrophobic materials requires complex processes and specialized equipment. Polyurethane (PU) is a promising as a material for superhydrophobic coatings because of its inherent advantages such as adhesion properties and mechanical toughness. In this study, a fluorinated polyurethane (FPU) solution was synthesized using a one-pot method. Further, two types of particles with varying solvent miscibility were blended into an FPU solution. The alterations in surface morphologies, resulting from variations in evaporation conditions due to the different particle compositions, were confirmed through scanning electron microscopy (SEM), which leads to a difference in hydrophobicity. The prepared coating material was shown to tiny thorn-like surface morphology, which allowed it to demonstrate a high water contact angle of 157°, along with additional anti-fouling properties. Furthermore, the resulting superhydrophobic coating materials demonstrate mechanical robustness under cyclic tape peel test even after 10 cycles and cross-cut test Our study offers an effective approach for achieving superhydrophobic properties while maintaining mechanical durability, thereby advancing the development of high-performance superhydrophobic materials.

The Effect of Carbon on Chitosan-ZnO Composites as Fabric Mask Coating Materials

Increasing the effectiveness of cloth masks can reduce the use of disposable medical masks which creates a new waste problem. In this research, the synthesis of zinc oxide nanoparticles was carried out using the precipitation method through the reaction between zinc nitrate and phosphoric acid as one of the ingredients in the chitosan-ZnO/C composite mixture. The carbon source is obtained from activated coconut shell carbon using sodium hydroxide. X-ray diffractometer (XRD) testing was carried out to determine the phase content of the synthesized carbon powder. XRD testing was also carried out on synthesized ZnO particles to determine the occurrence of phase transformations and to determine the quantitative and qualitative characteristics of the material. Fourier Transform Infrared testing was also carried out to observe functional group bonds formed in carbon compounds. Composite materials that have been successfully made will then be tested for hydrophobicity by calculating the contact angle. The results of this study indicate that the synthetic base material has been successfully carried out and the composite has been successfully made. The highest water contact angle is 106o was found in the chitosan/ZnO composite sample with a ratio of 2:1 and a mass variation of 0.05 gr active carbon.

Sustainable synthesis of superhydrophobic textile filters for oil/water separation using biomass waste-derived Bio-Ag nanoparticles.

Separation of oil and water has become a daunting task at a global scale due to the frequent presence of industrial oily wastewater. This study describes the synthesis of a Bio-Ag nanoparticle and its utilization in fabricating superhydrophobic (SH) films on textile fibers for separating oil-water mixture. The Bio-Ag nanoparticles were prepared from grape seed extract. The study examined various aspects of the synthesized SH textile fiber, including its morphology, wettability, surface composition, chemical stability, mechanical stability, oil absorption capacity, oil-water separation performance, and flux rate. The results indicate that the developed Bio-Ag-based SH textile filter has excellent SH properties, with a low water sliding angle of 1° and a high water contact angles of 159°. The SH textile filter exhibited good separation efficiency, oil absorption capacity, and flux rate toward silicone oil, toluene, and petroleum ether. The SH textile filter also demonstrated satisfactory chemical and mechanical stability. The developed Bio-Ag-based SH textile filter has the potential to be an efficient material for oil-water separation applications.

Effects of facile chemical pretreatments on physical-chemical properties of large clustered and small monopodial bamboo microfibers isolated by steam explosion

To explore the facile and high-efficient combining isolation method of bamboos and develop their high value-added fiber functional materials, this study aims at investigating the effects of four chemical soaking-pretreatments on physical-chemical properties of bamboo microfibers that were isolated using eco-friendly steam explosion (SE) from four local bamboo species (Chimonobambusa quadrangularis (CQ), Qiongzhuea tumidinoda (QT), Dendrocalamus giganteus (DG), and Dendrocalamus sinicus (DS)). The variations in the micro-morphology, width distribution and major chemical composition of bamboo microfibers as well as their thermal stability, crystallinity, surface hydrophilicity, and macro- and nano- mechanical properties were comprehensively characterized. The CQ, QT, DG, and DS bamboo microfibers obtained by the combination of mild alkali pretreatment and steam explosion displayed the smallest width sizes (149.57, 150.76, 177.33, and 172.67 µm), the highest cellulose contents (68.14 %, 67.62 %, 67.92 %, and 62.36 %), and the lowest hemicellulose contents (12.64 %, 17.24 %, 15.94 %, and 16.42 %) compared to their controls. Four chemical soaking pretreatments improved the thermal stability of bamboo microfibers but generally reduced their macro- and nano-mechanical properties. The elongation at break of bamboo microfibers pretreated by mild alkaline were effectively elevated. Acid-pretreated bamboo microfibers effectively increased the hydrophobicity of cellulose microfibrils with the highest water contact angle (WCA) value (56.8°). IL-pretreated bamboo microfibers improved the surface roughness and hydrophilicity (WCA=44.3°).

Scalable fabrication of a robust asymmetric superwetting Janus mesh by facile spray-coating for oil–water emulsions separation

Janus membrane with asymmetric wettability are emerging separation materials for the purification of emulsified oil–water mixtures, however, their poor mechanical durability and low-flux without external pressure severely limit their practical application. Herein, a robust superwetting Janus mesh demonstrating a high water contact angle (WCA) difference up to 157° was developed by simply spraying on the stainless steel mesh (SSM), via the superhydrophobic fluorocarbon resin/polyvinylidene fluoride/1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane modified titanium dioxide@carboxylated CNTs (FEVE/PVDF/F-TiO2@CNTs) layer and a superhydrophilic layer consisting epoxy resin/ethylene imine polymer/sodium perfluorooctanoate modified bentonite (EP/PEI/F-Bentonite). By carefully adjusting the surface polar-nonpolar molecule repulsion based on the two oppositely bond energy side and incorporating nano/microstructures to form a stable interfacial oiling/hydration layer, the robust Janus mesh achieved interface demulsification and gravity separation of emulsified oil–water mixtures. The prepared Janus SSM exhibited excellent gravity-driven separation performance, achieving a flux up to 1508.6 L m−2h−1 for water-in-oil (W/O) emulsions, and 843.1 L m−2h−1 for oil-in-water (O/W) emulsions. Additionally, it exhibited high separation efficiency with water rejection above 99.9 % and oil rejection above 99.7 %. Moreover, the prepared Janus mesh with fine uniform nano/microstructures and functionalized groups demonstrated notable reusability and mechanochemical stability after 10 cycles of O/W and W/O emulsion filtration, 100 cycles of sandpaper abrasion, and strong acid/alkali immersion for 7 d. Overall, this study expected to facilitate the fabrication of a robust asymmetric superwetting Janus mesh with enhanced separation properties for highly efficient oily wastewater treatment.

Enhanced Corrosion Resistance and Surface Wettability of PVDF/ZnO and PVDF/TiO2 Composite Coatings: A Comparative Study

This study aims to enhance the practical performance of PVDF/ZnO and PVDF/TiO2 composite coatings known for their distinctive properties. The coatings, applied through spray coating with PVDF and ZnO or TiO2 nanoparticles on glass, steel, and aluminum substrates, underwent a comprehensive evaluation. Surface wetting properties and morphology were respectively evaluated using a technique involving liquid droplets and an imaging method using high-energy electrons. Potentiodynamic polarization was used to compare corrosion resistance between coated and bare substrates. Nanoindentation was used to assess coating hardness, and bonding strength was subsequently quantified. The results revealed that PVDF/ZnO composite coatings had higher water contact angles (161 ± 5° to 138 ± 2°) and lower contact angle hysteresis (7 ± 2° to 2 ± 1°) compared to PVDF/TiO2 and PVDF coatings. Moreover, corrosion tests demonstrated superior protection for steel and aluminum surfaces coated with superhydrophobic PVDF/ZnO. Nanoindentation indicated enhanced mechanical properties with TiO2 nanoparticles, with adhesion results favoring TiO2 over ZnO nanoparticles.

Controlling Superhydrophobicity on Complex Substrates Based on a Vapor-Phase Sublimation and Deposition Polymerization.

The superhydrophobic properties of material surfaces have attracted significant research and practical development in a wide range of applications. In the present study, a superhydrophobic coating was fabricated using a vapor-phase sublimation and deposition process. This process offers several advantages, including a controllable and tunable superhydrophobic property, a dry and solvent-free process that uses well-defined water/ice templates during fabrication, and a coating technology that is applicable to various substrates, regardless of their dimensions or complex geometric configurations. The fabrication process exploits time-dependent condensation to produce ice templates with a controlled surface morphology and roughness. The templates are sacrificed via vapor sublimation, which results in mass transfer of water vapor out of the system. A second vapor source of a polymer precursor is then introduced to the system, and deposition occurs upon polymerization on the iced templates, replicating the same topologies from the iced templates. The continuation of the co-current sublimation and deposition processes finally renders permanent hierarchical structures of the polymer coatings that combine the native hydrophobic property of the polymer and the structured property by the sacrificed ice templates, achieving a level of superhydrophobicity that is tunable from 90° to 164°. The experiments demonstrated the use of [2,2]paracyclophanes as the starting materials for forming the superhydrophobic coatings of poly(p-xylylenes) on substrate surfaces. In comparison to conventional vapor deposition of poly(p-xylylenes), which resulted in dense thin-film coatings with only a moderate water contact angle of approximately 90°, the reported superhydrophobic coatings and fabrication process can achieve a high water contact angle of 164°. Demonstrations furthermore revealed that the proposed coatings are durable while maintaining superhydrophobicity on various substrates, including an intraocular lens and a cardiovascular stent, even against harsh treatment conditions and varied solution compositions used on the substrates.

Derivatives of linseed oil and camelina oil as monomers for emulsion polymerization

Acrylated methyl esters of higher fatty acids derived from camelina oil and linseed oil were synthesized through transesterification, epoxidation, and subsequent acrylation. Methyl methacrylate and butyl acrylate were copolymerized with various amounts of bio-based derivatives (5 – 30 wt% in monomer mixture) to obtain polymeric latexes for coating applications. Successful emulsion polymerizations with up to 25 wt% of the bio-based derivatives were performed with low coagulum (below 2%) and high monomer conversion (around 95%). The incorporation of bio-based derivatives into polymeric latexes was confirmed with infrared spectroscopy. Asymmetric flow field flow fractionation coupled with a multi-angle light scattering was used to analyze the synthesized copolymers in terms of their molar mass distribution. The results revealed that copolymerizing the bio-based derivatives resulted in ultra-high molar mass nanogel fractions formed because of multi-acrylated ingredients derived from polyunsaturated fatty acids. The phenomenon of nanogel formation became more pronounced for the linseed oil-based derivative. Evaluated coating properties showed that latexes comprising the bio-based derivatives provided increased water repellence (about 10° higher water contact angles were achieved for all bio-based coating compositions in contrast to a reference latex). Moreover, latexes comprising chemically modified oils in the content of 25 and 30 wt% provided water whitening-resistant coatings, making the bio-based derivatives promising candidates for replacing petroleum-based monomers in the production of sustainable latex coatings.Graphical abstract

Preparation and performance testing of corn starch/pullulan/gallic acid multicomponent composite films for active food packaging.

The present study investigated the mechanical characteristics, hydrophobicity, antioxidant and antibacterial properties, FTIR, SEM and XRD of films fabricated with corn starch and pullulan (CS/PUL) by adding different concentrations of Gallic acid (GA) (0%, 0.5%, 1.0%, 1.5% w/v). The mechanical strength and opacity of CS/PUL films were enhanced by the addition of 1.0% GA. The water vapor permeability (WVP) of CS/PUL films was significantly lower in films with GA compared to those without (P < 0.05). The addition of GA, especially at concentrations of 1.0% and 1.5%, resulted in considerably better free radical scavenging activities on DPPH than films without GA (P < 0.05). Interestingly, the highest water contact angle (WCA) value was observed in films with 0.5% GA, indicating stronger hydrophobicity. Furthermore, the antibacterial capabilities of the films, particularly against E. coli and P. aeruginosa, improved with an increase in GA concentration. The results of FTIR, SEM and XRD analyses showed that GA was well distributed in the CS/PUL matrix.

Fabrication, Characterization, and In Vitro Cytotoxicity Assessment of Tri-Layered Multifunctional Scaffold for Effective Chronic Wound Healing.

Chronic wounds have been a global health risk that demands intensive exploration. A tri-layered biomaterial scaffold has been developed for skin wounds. The top layer of the scaffold is superhydrophobic, and the bottom layer is hydrophilic, both of which were electrospun using recycled expanded polystyrene (EPS) and monofilament fishing line (MFL), respectively. The intermediate layer of the scaffold comprised hydrogel by cross-linking chitosan (CS) with polyethylene glycol. The surface morphology, surface chemistry, thermal degradation, and wettability characteristics of each layer of the scaffold were examined. Also, the antibacterial activity and in vitro cytotoxicity study on the combined tri-layered scaffold were assessed against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Data revealed exceptional water repellency of the heat-treated electrospun top superhydrophobic layer (TSL) with a high-water contact angle (WCA) of 172.44°. A TSL with 15 wt% of micro-/nano-inclusions had the best thermal stability above 400 °C. The bottom hydrophilic layer (BHL) displayed a WCA of 9.91°. Therapeutically, the synergistic effect of the combined tri-layered scaffold significantly inhibited bacteria growth by 70.5% for E. coli and 68.6% for S. aureus. Furthermore, cell viability is enhanced when PEG is included as part of the intermediate CS hydrogel layer (ICHL) composition.

Preparation of a Wear-Resistant, Superhydrophobic SiO2/Polymethyl Methacrylate Composite Coating on Aluminum Surface Processed with Nanosecond Laser.

Superhydrophobic coatings are limited by complex preparation processes and poor mechanical durability in practical applications. In this study, a mechanically robust superhydrophobic composite coating was applied to an aluminum surface that underwent processing with a nanosecond laser (referred to as a superhydrophobic aluminum surface). It exhibits a high water contact angle (WCA) of 158.81°, a low sliding angle (SA) of less than 5°, and excellent self-cleaning ability. The wear test shows its durability, and the corrosion test shows its excellent corrosion resistance. This study provides a framework for the preparation of robust superhydrophobic surfaces that may have potential applications in many fields.

Spherosilicate-modified epoxy coatings with enhanced icephobic properties for wind turbines applications

Industries around the world use active methods, which include thermal, mechanical and chemical approaches, to reduce icing on aerodynamic surfaces such as wind turbines and aircraft. However, they are often inefficient, costly, and pollute the environment. For years, new coatings with anti-icing properties (so-called icephobic coatings) have been developed to either replace or work in tandem with active systems. In this study, coatings were designed based on an epoxy gelcoat commonly used for wind turbines through chemical modification with spherosilicate derivatives. Di- and tri-functional spherosilicates have both groups that increase the degree of hydro-/icephobicity of composites and groups capable of interacting with epoxy resin and amine hardener. The icephobicity of the surface was determined using ice adhesion. The lowest value of this parameter reached a value of 186 kPa, a 30 % reduction compared to the unmodified coating. In addition, the hydrophobicity of the surface was determined (the highest water contact angle was equal to 103°). A correlation was observed, proven in many works, that as the surface roughness increases, the anti-icing properties deteriorate. For individual modifications, it was also shown that hydrophobicity has a positive effect on ice adhesion. The work also examined the surface zeta potential and determined the durability of the properties after 100 icing/deicing cycles.

Parameters Affecting Interfacial Assembly and Alignment of Nanotubes.

Tangential flow interfacial self-assembly (TaFISA) is a promising scalable technique enabling uniformly aligned carbon nanotubes for high-performance semiconductor electronics. In this process, flow is utilized to induce global alignment in two-dimensional nematic carbon nanotube assemblies trapped at a liquid/liquid interface, and these assemblies are subsequently deposited on target substrates. Here, we present an observational study of experimental parameters that affect the interfacial assembly and subsequent aligned nanotube deposition. We specifically study the water contact angle (WCA) of the substrate, nanotube ink composition, and water subphase and examine their effects on liquid crystal defects, overall and local alignment, and nanotube bunching or crowding. By varying the substrate chemical functionalization, we determine that highly aligned, densely packed, individualized nanotubes deposit only at relatively small WCA between 35 and 65°. At WCA (< 10°), high nanotube bunching or crowding occurs, and the film is nonuniform, while aligned deposition ceases to occur at higher WCA (>65°). We find that the best alignment, with minimal liquid crystal defects, occurs when the polymer-wrapped nanotubes are dispersed in chloroform at a low (0.6:1) wrapper polymer to nanotube ratio. We also demonstrate that modifying the water subphase through the addition of glycerol not only improves overall alignment and reduces liquid crystal defects but also increases local nanotube bunching. These observations provide important guidance for the implementation of TaFISA and its use toward creating technologies based on aligned semiconducting carbon nanotubes.

Self-healing and malleable waterborne polyurethane bearing aliphatic disulfide linkages with hydrophobic branching chains

Self-healing polymers have attracted extensively interests to improving durability of materials. A promising strategy to prepare self-healing materials is the incorporation of dynamic disulfide bonds into polymer backbones. In this study, a novel hydrophobic chain extender containing disulfide bond (CY-OA) has been successfully synthesized and used to elevate the practical application capability of the self-healing WPU. FT-IR and Raman spectra confirmed that the disulfide bonds were successfully incorporated into the polyurethane backbones. The synthetic self-healing waterborne polyurethanes (SHWPUs) all had the high-water contact angle above 108° and the low water absorption below 5%, exhibiting the good hydrophobicity and water resistance. Increasing addition of CY-OA simultaneously optimized the mechanical properties and self-healing efficiency of SHWPUs. The mechanical properties of repaired SHWPU-4 film had been almost recovered to its original values (tensile strength and elongation at break were 12.79 MPa and 1003%) at 120 °C for 1 h. Meanwhile, the feature of dynamic disulfide bonds produced a relatively low activation energy of 54.78 kJ/mol, resulting in a good self-healing efficiency of 93%. Therefore, this hydrophobic self-healing WPU contributed the scratch resistance, water resistance, reprocess ability and further got the feasibility of practical applications.

Recyclable Superhydrophobic Surface Prepared via Electrospinning and Electrospraying Using Waste Polyethylene Terephthalate for Self-Cleaning Applications.

Superhydrophobic surfaces, i.e., surfaces with a water contact angle (WCA) ≥ 150°, have gained much attention as they are multifunctional surfaces with features such as self-cleaning, which can be useful in various applications such as those requiring waterproof and/or protective films. In this study, we prepared a solution from recycled polyethylene terephthalate (PET) and fabricated a superhydrophobic surface using electrospinning and electrospraying processes. We observed that the fabricated geometry varies depending on the solution conditions, and based on this, we fabricated a hierarchical structure. From the results, the optimized structure exhibited a very high WCA (>156.6°). Additionally, our investigation into the self-cleaning functionality and solar panel efficiency of the fabricated surface revealed promising prospects for the production of superhydrophobic surfaces utilizing recycled PET, with potential applications as protective films for solar panels. Consequently, this research contributes significantly to the advancement of environmentally friendly processes and the progress of recycling technology.