Water Adhesion Research Articles

Development of Biodegradable and Recyclable FRLM Composites Incorporating Cork Aggregates for Sustainable Construction Practices

Reducing energy consumption in the building sector has driven the search for more sustainable construction methods. This study explores the potential of cork-modified mortars reinforced with basalt fabric, focusing on optimizing both mechanical and hygroscopic properties. Six mortar mixtures were produced using a breathable structural mortar made from pure natural hydraulic lime, incorporating varying percentages (0–3%) of cork granules (Quercus suber) as lightweight aggregates. Micro-computed tomography was first used to assess the homogeneity of the mixtures, followed by flow tests to evaluate workability. The mixtures were then tested for water absorption, compressive strength, and adhesion to tuff and clay brick surfaces. Adhesion was measured through pull-off tests, to evaluate internal bonding strength. Additionally, this study examined the relationship between surface roughness and bond strength in FRLM composites, revealing that rougher surfaces significantly improved adhesion to clay and tuff bricks. These findings suggest that cork-reinforced mortars offer promising potential for sustainable construction, achieving improved hygroscopic performance, sufficient mechanical strength, internal bonding, and optimized surface adhesion.

Development of low-molecular-weight polysaccharide-based wound dressings for full-thickness cutaneous wound healing via coacervate formation

The development of polysaccharide-based wound dressings that are easy to prepare, adhere to tissue, adapt to diverse shapes and exhibit tunable mechanical properties holds significant clinical interest. This study introduced a simple spontaneous liquid-liquid phase separation technique employing low-molecular-weight and high polyion concentration of chitosan (CS) and hyaluronic acid (HA) to fabricate CS/HA coacervates. Upon increasing the molecular weight of chitosan from 7 kDa to 250 kDa, a transition in the CS/HA coacervates from liquid-like state to an elastic liquid and eventually to a solid-like state was observed. The resulting CS/HA coacervates demonstrated robust water resistance and adhesion to skin tissue. Notably, the molecular weight of chitosan significantly influenced the mechanical properties and hydration levels of the CS/HA coacervates. Moreover, in vivo studies using a full-thickness cutaneous defect model revealed that the CS/HA coacervates, prepared using 100 kDa chitosan, markedly accelerate wound healing. The coacervates' ease of preparation, wet adhesion, heterogeneous structure, suitability for irregularly shaped wounds, and exceptional wound healing promotion of the coacervates qualify them as an optimal wound dressing.

Facile and effective construction of superhydrophobic, multi-functional and durable coatings on steel structure

Nowadays, steel is one of the most significant materials in industry and daily life. Unfortunately, the defects of steel structures such as collapse at high temperature, poor corrosion resistance, and bad surface functionality have severely restricted their further application. Applying functional coatings for steel structures is considered the effective strategy for settling theses disadvantages. Inspired by nature, eco-friendly, superhydrophobic, and multifunctional-integrated coatings were fabricated on steel via one-step spraying strategy in this paper. Along with silicon dioxide (SiO2) nanoparticles and epoxy resin/silicone resin (EP/SR), the coatings are jointly constituted by hydrophobic flame retardants (M-ALHP@ZIF-8) prepared via multi-stage modification. Due to the formation of micro/nano-scaled rough structure with low surface energy, the water contact angle (WCA) and water sliding angle (WSA) of as-prepared coatings can reach 162.4° ± 1.2° and 2.8° ± 0.4°. The water repellency with low water adhesion can endow the surface of steel with excellent self-cleaning, anti-fouling, and long-lasting anti-corrosion ability. Additionally, the superhydrophobic coatings have displayed good mechanical robustness, chemical stability and weather resistance, which can exhibit certain actual values. Accorded with Zn-catalyzed charring effect of flame retardants, as-prepared coatings have possessed outstanding fire protection capacity with the lowest backside temperature of 181 °C after 1 h fire impact tests. Consequently, this work has provided a facile and effective route for synchronously tackling the key challenges of poor fire protection and surface functionality for steel structures, which will be expected to pave the wide pathway for constructing multifunctional coatings in more fields.

One-step hydrothermal method for long-term anti-corrosion lanthanum-based superhydrophobic coating on Mg alloy

The superhydrophobic coating was created on the surface of AZ31B using a one-step hydrothermal method. Various characterisation techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), contact angle goniometer, and electrochemical workstation, were employed to characterise its morphology, composition, hydrophobicity and corrosion resistance. The prepared coating from a 5-hour hydrothermal reaction exhibited a double-layer structure with a dense inner oxide layer and an outer layer of needle-like micro-nano structures. Achieving a water contact angle (WCA) as high as 159°, the superhydrophobic coating demonstrated low water adhesion and excellent self-cleaning properties. In a 3.5 wt-% NaCl aqueous solution, its corrosion rate was 5 orders of magnitude lower than that of the bare Mg alloy. Furthermore, the coating maintained a high impedance modulus value at 0.01 Hz (∼6.85 × 106 Ω cm2) after immersion in 3.5 wt-% NaCl solution for 25 days, which was attributed to the synergistic effect of the inner and outer layers. This study introduces a strategy for preparing long-term corrosion-resistant superhydrophobic coating on Mg alloy.

Barnacle-inspired amphipathic high strength adhesives under-water/oil

Adhesives designed for bonding in liquid environments have a broad application prospect. In general, amphiphilic polymer structures are important research objects for underwater bonding. And in the study of underwater adhesives, it was found that they can quickly dispel or absorb interfacial water and form reliable bulk strength and adhesion strength. However, achieving strong adhesion in both water-based and oily environments poses a significant challenge. In this work, an adhesive inspired by barnacles that can meet the bonding requirements in both water-based and oily environments has been prepared. Hydrophilic (polyethylene glycol (PEG)) main chains and hydrophobic (1-Octadecyl thiol (ODT)) side chains are simultaneously integrated into the polyurethane structure. Different from the past, hydrophobic and hydrophilic segments are included in the hard segment and soft segment microregion, respectively; At the same time, both hydrophilic and hydrophobic chain segments have strong crystallization, which greatly strengthens the driving force of molecular segments migration and phase separation compared with ordinary hydrophilic/hydrophobic structures. Water-based and oil-based solvents drive hydrophilic and hydrophobic molecular chains to diffuse to the surface, respectively, which enhances the adhesive strength to hydrophilic and hydrophilic surfaces, respectively. In comparison to the adhesion strength observed in air, the adhesion strength of the adhesive to polymethyl methacrylate (PMMA) increases by 1.72 times in oil environments (from 1.02 to 1.75 MPa). Similarly, the adhesion strength to aluminum (Al) increases by 2.23 times under water (from 1.82 to 4.04 MPa). These findings suggest that the regulation strategy for polymer chains employed in this study holds great potential for advancing adhesive performance in diverse environments.

Gelatin/Dopamine/Zinc-Doped Ceria/Curcumin nanocomposite hydrogels for repair of chronic refractory wounds

Chronic wound healing is a common clinical challenge, characterized by bacterial infection, protracted inflammatory response, oxidative stress, and insufficient neovascularization. Nanozymes have emerged as a promising solution for treating skin wounds due to their antioxidant, antibacterial, and angiogenic properties. In recent years, combining nanozymes with hydrogels to jointly promote wound healing has attracted increasing research interest. However, most of the current nanocomposite hydrogels are still not effective in simultaneously controlling inflammatory, oxidative stress and bacterial invasion in wound healing. Improving the therapeutic functional diversity and efficacy of nanocomposite hydrogels remains a problem that needs to be addressed. In this study, we prepared nanocomposite hydrogels (GelMD-Cur@ZHMCe) by combining methylacrylated gelatin modified with dopamine (GelMD) with Zinc-doped hollow mesoporous cerium oxide nanoparticles loaded with curcumin (Cur@ZHMCe). The resulting hydrogels exhibited excellent water absorption, adhesion, and biocompatibility. In vitro and in vivo studies have demonstrated that GelMD-Cur@ZHMCe has excellent antioxidant, antibacterial, anti-inflammatory and vasculature-promoting properties, which enable it to rapidly promote wound repair. The wound healing rate of the rat total skin defect infection model treated with GelMD-Cur@ZHMCe reached 98.5±4.9 % after 14 days of treatment. It was demonstrated that this multifunctional nanocomposite hydrogel provides a promising therapeutic strategy for skin repair.

Analysis of Freeze-Thaw Damage of Cement Mortars Doped with Polyethylene Glycol-Based Form Stable Phase Change Materials.

The development of construction materials with the integration of phase change materials (PCMs) has been a topic of wide interest in the scientific community, especially in recent years, due to its positive impact on temperature regulation inside buildings. However, little is known about the behavior of materials doped with PCMs when exposed to accidental or severe environments. Currently, a large area of the planet experiences seasonal freeze-thaw effects, which impact the durability and performance of construction materials. Accordingly, the main objective of this study was to evaluate the damage caused by cyclic freeze-thaw actions on the behavior of a cement mortar, including a PEG-based form-stable PCM. An experimental methodology was developed based on the physical and mechanical characterization of mortars under normal operating conditions and after being subjected to freeze-thaw cycles. The results indicated that, under normal exposure conditions, the incorporation of aggregate functionalized with PCM led to a decrease in the mortar's water absorption capacity, compressive strength, and adhesion. However, its applicability has not been compromised. Exposure to freeze-thaw cycles caused a loss of mass in the specimens and a decrease in the compressive strength and adhesion capability of the mortar.

Boosting electrochemical performance of single-walled carbon nanotube three-dimensional architectures through appropriate selection of organic dispersant

The choice of organic dispersant in the fabrication of 3D carbon nanotube architectures affects their macroscopic properties. Binder-free papers (referred to as buckypapers, BPs) consisting of single-walled nanotubes (SWCNTs) fabricated by vacuum filtration of nanotube suspensions in isopropanol, ethanol, benzoic acid dissolved in ethanol and lemon oil show a work of adhesion of water that varies from 25.7 to 112.2 mJ·m−2. Bulk electrical resistivity also changes significantly from 145 to 1010 mΩ cm. Raman and FTIR spectra of pristine SWCNTs and BPs show evidence of permanent adsorption of organic molecules on SWCNTs. Heterogeneous electron transfer (HET) standard rate constants, k0, for ferro/ferricyanide and hexaammineruthenium(II)/(III) redox probes estimated from cyclic voltammetry measurements on BP electrodes vary from 12.6×10−4cms−1 to 32.7×10−4cms−1 and 12.8×10−4cms−1 to 26.0×10−4cms−1, respectively, depending on the dispersant used. Calculations using the Gerischer-Marcus model show that molecules adsorbed act as electron donors that boost HET kinetics and cause a shift in the reaction half-wave potential. The level of doping of nanotubes depends on the dipole moment of the dispersant molecules and proton affinity. Thus, the electrocatalytic activity of three-dimensional architectures composed of nanotubes can be adjusted by selecting an appropriate dispersant.

Adhesion and adsorption properties of water, ethanol, rhamnolipid and Triton X-165 mixture in quartz-mixture-air system

Wetting behaviour of the solutions including water, ethanol (ET), rhamnolipid (RL) and Triton X-165 (TX165) with regard to the quartz surface tension was investigated. The investigations were based on the measurements of the contact angle on the quartz surface for the solutions at the constant ET and RL concentrations and variable of TX165. The obtained results were considered with regard to the adhesion work of the solution to the quartz surface, adsorption of particular components of the solution at the quartz-air, quartz-solution and solution-air interfaces as well as to solution interactions across the quartz-solution interface. The considerations of the adhesion work and parameter of solution interactions across the quartz-solution interface as well as the adsorption of ET, RL and TX165 at different interfaces were based on the quartz surface tension and its components determined by different methods. These research results allow to establish the correlations between the adhesion work and the adsorption film pressure at the quartz-air interface and those between the parameter of interactions at the quartz-solution interface and its tension. The mechanism of the adsorption of particular components of the solution at the interfaces and their standard Gibbs free energy of adsorption were also discussed.

Experimental Investigation of Runback Water Flow Behavior on Aero-Engine Rotating Spinners with Different Wettabilities

The accumulation of ice on the aero-engine inlet compromises engine safety. Traditional hot air anti-icing systems, which utilize bleed air, require substantial energy, decreasing engine performance and increasing emissions. Superhydrophobic materials have shown potential in reducing energy consumption when combined with these systems. Research indicates that superhydrophobic surfaces on stationary components significantly reduce anti-icing energy consumption by altering runback water flow behavior. However, for rotating aero-engine components, the effectiveness of superhydrophobic surfaces and the influence of surface wettability on runback water flow remain unclear due to centrifugal and Coriolis forces. This study investigates the runback water flow behavior on aero-engine rotating spinner surfaces with varying wettabilities in a straight-flow spray wind tunnel. The results demonstrated that centrifugal force reduces the amount of runback water on the rotating spinner compared to the stationary surface, forming rivulet flows deflected opposite to the direction of rotation. Furthermore, wettability significantly affects the flow characteristics of runback water on rotating surfaces. As the contact angle increases, the liquid water on the rotating spinner transitions from continuous film flow to rivulet and bead-like flows. Notably, the superhydrophobic surface prevents water adhesion, indicating its potential for anti-icing on rotating components. In addition, the interaction between rotational speed and surface wettability enhances the effects, with both increased rotational speed and larger contact angles contributing to higher liquid water flow velocities, promoting the rapid formation and detachment of rivulet and bead-like flows.

Bioinspired starch nanofibrous films with tunable hydrophobicity and water adhesion via tannic acid-interfacial self-assembly for food packaging

To address the limitations in water resistance and functionality of existing starch-based food packaging materials, this study developed a new sustainable food packaging material—starch nanofibrous films (SNFs) enhanced with an acylated tannic acid (ATA) interfacial self-assembly coating. Inspired by the unique hydrophobicity and water adhesion properties of rose petals, which effectively control surface characteristics to maintain microenvironmental humidity during food processing and storage, this approach significantly enhanced the water resistance, stability, and mechanical strength of the material. Specifically, the obtained SNFs/ATA exhibited a maximum water contact angle of ∼ 134.1°, tensile strength of ∼ 0.86 MPa, and Young’s modulus of ∼ 43.48 MPa. Moreover, SNFs/ATA showed excellent antibacterial and antioxidant properties, UV-blocking capabilities, and degradability, making it an environmentally friendly choice for food packaging. In practical food preservation applications, cherry tomatoes packaged with SNFs/ATA showed a significant extension of shelf life to 15 days, with a 62.5 % reduction in spoilage rate, a 25.4 % decrease in weight loss, and good quality including pulp firmness, pH, titratable acidity, and total soluble solids. This work demonstrates structurally regulated polyphenol assembly in the preparation of all-natural green biomimetic surface, creating new opportunities for the development of sustainable bio-based food packaging systems.

Organofluorosilicon Modified Polyacrylate with the Unidirectional Migration Promotion of Disperse Dyes toward Polyester Fabric for Wash-Free Digital Inkjet Dyeing.

The printing and dyeing industry is currently accelerating toward a direction of high efficiency, energy conservation, environmental protection, and integration with digitalization. Disperse dye wash-free digital inkjet dyeing is a revolutionary breakthrough for cleaning and coloring polyester fabric. Based on the solubility parameters and the hot-melt dyeing characteristics of disperse dyes, soft, hard, and functional monomers of acrylate were used as the main body. Moreover, single-vinyl fluorinated polysiloxane and divinyl polysiloxane with low solubility parameters were used as modified monomers. A modified polyacrylate (PFSMA) adhesive containing silicon in the main chain and fluorine silicon in the side chain was prepared via miniemulsion polymerization. Using disperse digital inkjet dyeing of polyester fabric without washing can realize energy saving, emission reduction, and carbon reduction. Results showed that the optimum preparation conditions of PFSMA were as follows: DVFS molecular weight of 957 g/mol and DVFS content of 2.5 wt %. Compared with that of polyacrylate (PA), the glass-transition temperature of PFSMA film decreased, and its water resistance, toughness, and adhesion enhanced. When the PFSMA content in the wash-free disperse red ink was 8 wt %, the color yields of the front and back of the PFSMA jet-dyed polyester fabric were 18.86 and 13.28, respectively. Moreover, the color yield of the front of PFSMA jet-dyed polyester fabric was 39.9% higher than that of the pure liquid disperse red jet-dyed fabric. The simulated fixation rate was 87.9%, approximately 2.9 times higher than that of the PA wash-free jet-dyed fabric. The color fastness to dry rubbing reached level 4 and the color fastness to wet rubbing reached level 3-4, which was one level higher than that of pure liquid disperse red jet-dyed fabrics. The color fastness to soaping reached grade 5 and the color fastness to heat compression reached grades 4-5 and above. The fabric was a little firmer but smoother. The color properties, color fastness, and hand feeling of the PFSMA wash-free jet-dyed polyester fabric exceeded the levels of commercially available adhesives.

Dual cross-linking mechanism of sodium alginate composite hydrogel for adhesive microneedle patch preparation

The introduction of microneedles has revolutionized transdermal drug delivery. However, solid microneedle patches often fail to conform to the epidermis and adapt to changes in skin curvature, limiting their effectiveness. Using sodium alginate hydrogel to create flexible microneedle patches can address this issue, but conventional sodium alginate hydrogels suffer from inhomogeneous structure, dehydration, and poor mechanical properties. These drawbacks result in reduced drug delivery efficacy and insufficient mechanical robustness. To enhance the performance of sodium alginate hydrogels, this study presents a novel sodium alginate composite hydrogel with a dual cross-linking mechanism. The hydrogel, with a gelatin to sodium alginate ratio of 1:1, exhibited optimal surface morphology and mechanical properties suitable for microneedle patch preparation. The resulting microneedle patch demonstrated excellent water adhesion, securely attaching to skin and oral mucosa surfaces. In vitro experiments confirmed the microneedle's ability to puncture and release the drug, dissolving and releasing the drug within 15 minutes. The patch also showed superior piercing and dissolution properties on the mouth palate, highlighting it may serve as a potential delivery location for more efficient microneedle patch drug administration. In the future, this technology will show great potential in expanding the scope of drug administration for transdermal drug delivery and in reducing the work pressure of healthcare professionals.

Enhancing bioactivity and biocompatibility of polyetheretherketone (PEEK) for dental and maxillofacial implants: A novel sequential soaking process

Polyetheretherketone (PEEK) exhibits excellent biocompatibility, fatigue resistance, and an elastic modulus similar to bone, presenting broad application prospects in the field of dental and maxillofacial implants. However, the bioinertness of PEEK limits its applications. In this study, we developed a method to generate biocompatible and bioactive PEEK through a simple sequential soaking process, aimed at inducing bone differentiation and enhancing antibacterial properties. Initially, a three-dimensional (3D) porous network was introduced on the PEEK surface by soaking in concentrated sulfuric acid and water. Subsequently, the sulfonated PEEK surface was treated with oxygen plasma, followed by immersion in a dopamine solution to coat a polydopamine (PDA) layer. Finally, polydopamine phosphate ester-modified 3D porous PEEK was obtained through the reaction of phosphoryl chloride with surface phenolic hydroxyl groups. Systematic studies were conducted using scanning electron microscopy, X-ray photoelectron spectroscopy, water contact angle analysis, cell proliferation and adhesion, osteogenic gene expression detection, alkaline phosphatase staining, alizarin red staining, and bacterial culture. Overall, compared to unmodified PEEK, the modified PEEK significantly enhanced in vitro cell proliferation and adhesion, osteogenic differentiation, and antibacterial properties. The simple surface modification measures combined in this study may represent a promising technology and could facilitate the application of PEEK in dental and maxillofacial implants.

Superhydrophilic Densely‐Packed Gecko‐Like Structures by Soft‐Template Electropolymerization

AbstractBio‐inspired by natural species and previous research works, nanotubes are prepared by soft‐template electropolymerization in micellar solution. Various thiophene‐based and carbazole‐based monomers are designed from a triphenylamine core. With one of the carbazole‐based monomers, which is fully conjugated and with a star‐like structure, gecko‐like surface structures are obtained even if the structure is not perfectly planar. Extremely long and densely packed‐microtubes are reached especially at constant potential. However, the surfaces are not both highly hydrophobic and with strong water adhesion, but are superhydrophilic. These wetting properties can be explained by a high surface energy (γSV)=41.9 mN m−1 compared to gecko foot even if the natural gecko feet are also chemically inhomogeneous, or by differences in the arrangement of the surface structures.

Solid-liquid particle flow sealing mucus (PFSM) in enhancing coalbed methane (CBM) recovery: Multiple-perspectives analysis and mechanism insights

The paper presents an in-depth investigation of solid-liquid two-phase particle flow sealing mucus (PFSM) for enhanced coalbed methane (CBM) recovery. PFSM is composed of solid waste particles such as fly ash and rubber particles. The PFSM is assessed using multiple-perspectives analysis, which includes measurements of water retention, pressure expansion, rheological characteristics, adhesion, wettability, microscopy and field case studies. Single-factor and multi-factor studies are used to optimize slurry material ratios. The results show that PFSM has outstanding water retention characteristics, with over 80 % retention for 30 days at 30 °C, and impressive expansion performance, with 9.52 % at 0.6 MPa. The shear thinning curve conforms to the Cross model. After 30 s, the final contact angle is 75.17 °, which is about 6 ° smaller than that of cement based materials. Field experiments show that, after applying PFSM, the drainage gas concentration can be improved at least 60 % comparing to other sealing materials. This research findings could offer novel insights into enhancing CBM extraction, indicating potential for safer and more efficient coal mine production.

Hydrophobic Coating on Metal Matrix Composites

Abstract: The combination of traditional aluminum metal matrix composites (MMCs) with innovative reinforcement materials offers promising avenues for enhancing material properties and expanding application domains. In this study, aluminum matrix composites reinforced with ZrB2 (zirconium diboride) particles were fabricated using a stir casting technique. The addition of ZrB2 to the aluminum matrix aimed to improve mechanical strength, wear resistance, and thermal stability. Following fabrication, the resulting composite specimens were subjected to a surface modification process involving the application of a superhydrophobic coating. The superhydrophobic coating, characterized by its extreme water repellency and self-cleaning properties, was applied to the surface of the aluminum-ZrB2 composites using a spray-coating method. The coating material consisted of a hydrophobic compound integrated with nanostructured particles, engineered to achieve a hierarchical surface morphology that mimics natural superhydrophobic surfaces. The coated specimens were evaluated for their water repellency, contact angle measurements, and durability under various environmental conditions. The results of this study demonstrated that the combination of aluminum metal matrix composites with ZrB2 reinforcement, coupled with the application of a superhydrophobic coating, yielded surfaces with exceptional water-repellent properties. The coated composites exhibited high contact angles and low water adhesion, indicative of their superhydrophobic nature. Furthermore, the durability tests revealed the robustness of the coating against mechanical abrasion and environmental exposure. Overall, the integration of aluminum-ZrB2 composites with a superhydrophobic coating holds significant promise for applications requiring water-resistant surfaces, suchas aerospace components, marine structures, and outdoor equipment. This researchcontributes to advancing the development of multifunctional materials with tailoredsurface properties, paving the way for improved performance and longevity in diverse engineering applications

Roughness-Mediated SI-Fe0CRP for Polymer Brush Engineering toward Superior Drag Reduction.

Surface-initiated iron(0)-mediated controlled radical polymerization (SI-Fe0CRP) with low toxicity and excellent biocompatibility is promising for the fabrication of biofunctional polymer coatings. However, the development of Fe(0)-based catalysts remains limited by the lower dissociation activity of the Fe(0) surface in comparison to Cu(0). Here, we found that, by simply polishing the Fe(0) plate surface with sandpaper, the poly(methacryloyloxy)ethyl trimethylammonium chloride brush growth rate has been increased significantly to 3.3 from 0.14 nm min-1 of the pristine Fe(0) plate. The excellent controllability of roughness-mediated SI-Fe0CRP can be demonstrated by customizing multicompartment brushes and triblock brushes. Furthermore, we found that the resulting polymer brush coatings exhibit remarkably low water adhesion (0.097 mN) and an outstanding drag reduction rate of 52% in water. This work provides a promising strategy for regulating the grafting rate of polymer brushes via SI-Fe0CRP for biocompatible marine drag reduction coatings.

Corrosion and Biofouling Behaviors of Self‐Organized Structures on Steel Surface Fabricated by Femtosecond Laser

Self‐organized ripple and pillar structures are fabricated on steel surface using femtosecond laser. Their wettability is investigated in terms of static contact angle, roughness, and chemical bonds. The pillar structure is treated in low surface energy solution to further improve its hydrophobicity. The corrosion and biofouling behaviors of the structures in sea water are investigated by electrochemical and chlorella immersion experiments, respectively. The results show that the ripple structure is hydrophilic with a static contact angle similar to the original surface, while the pillar structure is highly hydrophobic since it has higher roughness and amount of non polar chemical bonds. The pillar structure is further transferred to superhydrophobic through the low surface energy treatment. The improved hydrophobicity facilitates a better anti‐corrosion and anti‐biofouling behavior, and the superhydrophobic pillar structure exhibits the best performance due to its strongest ability to repel water and chlorella adhesion.

Innovative and cost-effective fabrication of fluorine-free superhydrophobic coating: Using polydimethylsiloxane/soil particles for surface modification

In this study, a simple, efficient, and environmentally friendly method was used to create fluorine-free superhydrophobic coatings. The coatings were prepared by modifying soil particles with polydimethylsiloxane. Different from the previously reported methods, the micro-/nanostructures of these coatings were formed using natural soil as the building block. The modified soil particles were analyzed using X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy to determine their elemental compositions and functional groups, respectively. The surface topography of the coatings was characterized by scanning electron microscopy and laser scanning confocal microscopy. The resulting superhydrophobic coatings exhibited exceptional wear resistance, with a contact angle of 166.2±2.5° and a sliding angle of 3.6±1.3°. The coatings also had extremely low water adhesion (62 μN) and demonstrated good mechanical, weather-resistant, and self-cleaning properties. These coatings can be applied to various materials such as cement, wood, and sponge, owing to their favorable comprehensive performance. The coatings are anticipated to find widespread application in outdoor industries.