Excellent Self-cleaning Performance Research Articles

Preparation and performance study of environmentally friendly and durable kaolin/PDMS/cotton fabrics superhydrophobic surface

In this research work, a fluorine-free, durable, and excellent self-cleaning and oil-water separation performance kaolin/polydimethylsiloxane/cotton fabrics (Kaolin/PDMS/cotton) superhydrophobic surface was successfully prepared. The morphology, wettability, and phase composition of the coating were characterized and tested using scanning electron microscopy (SEM), dynamic contact angle measuring instrument, and X-ray diffraction (XRD). The experimental results showed that the organic composite of hydrophobic modified kaolin particles and cotton fabrics was successfully achieved through the bridging effect of PDMS. A dense superhydrophobic micro-nano structure coating was constructed on the surface of cotton fibers, and the tested performance was excellent. Has good local anti-pollution performance for common coffee, Coca-Cola, dyeing water, and simulated dust; After being worn for a distance of 1200 centimeters under a load of 10KPa, the contact angle with water remained above 150°, indicating excellent durability of the coating; In addition, kaolin/PDMS/cotton also exhibited good oil/water separation performance. After 15 cycles of oil-water separation tests, the separation efficiency for gasoline and dichloromethane both exceeded 96%.

Regenerated SERS substrate based on Ag/AuNPs-TiO2-oxidized carbon cloth for detection of imidacloprid

Imidacloprid (IMI) are widely used in modern tea industry for pest control, but IMI residues pose a great threat to human health. Herein, we propose a regeneration metal-semiconductor SERS substrate for IMI detection. We fabricated the SERS sensor through the in-situ growth of a nano-heterostructure incorporating a semiconductor (TiO2) and plasmonic metals (Au, Ag) on oxidized carbon cloth (OCC). Leveraging the high-density hot spots, the formed Ag/AuNPs-TiO2-OCC substrate exhibits higher enhancement factors (1.92 × 108) and uniformity (RSD = 7.68%). As for the detection of IMI on the substrate, the limit of detection was lowered to 4.1 × 10−6 μg/mL. With a hydrophobic structure, the Ag/AuNPs-TiO2-OCC possessed excellent self-cleaning performance addressing the limitation of single-use associated with traditional SERS substrates, as well as the degradation capability of the substrate under ultraviolet (UV) light. Accordingly, Ag/AuNPs-TiO2-OCC showcases outstanding SERS sensing and regenerating properties, making it poised for extensive application in the field of food safety assurance.

A self-cleaning photocatalytic membrane loaded with Bi2O2CO3/In(OH)3 S-scheme heterojunction composites for removing tetracycline from aqueous solutions

Bi2O2CO3/In(OH)3 (BON) photocatalysts were synthesized by a one-pot method and loaded onto polyvinylidene fluoride (PVDF) membranes to obtain a Bi2O2CO3/In(OH)3/PVDF (BON-M) catalytic membrane system. The catalytic membranes demonstrated complete degradation of tetracycline within 40 min under visible light. They demonstrated robust photocatalytic activity across a broad pH range (5–11) and in the presence of coexisting ions. The membranes demonstrated excellent self-cleaning performance. Following exposure to light, the irreversible contamination decreased from 27.1 % to 4.7 % and the membrane’s permeability was almost completely restored. Moreover, the charge transfer mechanism at the S-scheme heterojunction interface of BON was demonstrated by Density functional theory and in-situ X-ray Photoelectron Spectroscopy characterisation, and the active sites involved in tetracycline’s degradation were identified. Meanwhile, the mechanism of the “anemone effect” of BON-M was demonstrated in conjunction with Electron paramagnetic resonance, and the intrinsic Some factors enhancing the membranes’ photocatalytic activity are specified.

Superhydrophobic cotton fabric based on aqueous paint for passive daytime radiative cooling

Passive daytime radiative cooling (PDRC) is a technology that dissipates excess heat to outer space without any energy consumption. Numerous PDRC materials have been developed recently. However, hazardous organic solvents are often used in the fabrication process of these PDRC materials, and most PDRC materials are easily contaminated. In this study, a new scalable eco-friendly aqueous paint without volatile organic compounds (VOCs) was developed by combining fluoroacrylate copolymer with high-scattering polysilsesquioxane particles. The solar reflectivity and emissivity of the cotton fabric coated with the aqueous paint (PDRC@CF) are significantly enhanced (reach 92.2 % and 92.7 %, respectively) due to the synergistic effect of fluoroacrylate copolymer and polysilsesquioxane. The PDRC@CF has a remarkable radiative cooling effect with a surface temperature 5.7 °C lower than the ambient air and 16.1 °C lower than the pristine cotton fabric under direct sunlight exposure. Moreover, the aqueous paint endows the PDRC@CF with a washable superhydrophobic surface, whose water contact angle is 150.1°and sliding angle is 2.3°, possessing excellent self-cleaning performance. The PDRC@CF effectively combining the properties of anti-fouling and radiative cooling, can be applied to outdoor product protection and other energy-efficient cooling fields.

Transparent, superhydrophobic, and flexible polyimide films with robust and durable imide/silica particles surface prepared via a sintering process

Recently, transparent superhydrophobic surfaces have attracted great interest due to their potential applications in various fields, such as skyscrapers, windows, glass doors, displays, and solar panels. However, flexible films with superhydrophobicity and transparency still face challenges in practical applications due to their lack of durability of the properties. Here, we report transparent, superhydrophobic, and flexible polyimide films with robust oligoimide/silica protrusion surface prepared by a simple sintering process, aiming to address the above issues. A transparent polyimide film (PIF) and nano-silica particles modified with an oligoimide (NSOI) were separately prepared, and the sintering between PIF and NSOI were performed to obtain PINSOI samples. Among PINSOIs, the optimal PINSOI-3 sample exhibited excellent superhydrophobicity, optical transmittance and tensile strength. After folding/torsion, sandpaper abrasion, tape peeling and acidic/basic immersion tests, its superhydrophobicity was maintained, indicating excellent mechanical and chemical durability of superhydrophobicity even under harsh conditions. Also, after a standard accelerated weathering test, its superhydrophobicity, transmittance and tensile strength were almost completely maintained, indicating the excellent weathering durability of PINSOI-3. These durability properties of PINSOI-3 could be attributed to that the sintering resulted in strong fusion between the NSOI particles and PIF by chain entanglement. PINSOI-3 showed excellent self-cleaning performance, and it can be applied as a self-cleaning film for flexible or curved solar cells and displays.

Antibacterial Hydrophilic ZnO Microstructure Film with Underwater Oleophobic and Self-Cleaning Antifouling Properties.

Super-hydrophilic and oleophobic functional materials can prevent pollution or adsorption by repelling oil, and have good circulation. However, traditional strategies for preparing these functional materials either use expensive fabrication machines or contain possibly toxic organic polymers, which may prohibit the practical application. The research of multifunctional ZnO microstructures or nanoarrays thin films with super-hydrophilic, antifouling, and antibacterial properties has not been reported yet. Moreover, the exploration of underwater oleophobic and self-cleaning antifouling properties in ZnO micro/nanostructures is still in its infancy. Here, we prepared ZnO microstructured films on fluorine-doped tin oxide substrates (F-ZMF) for the development of advanced self-cleaning type super-hydrophilic and oleophobic materials. With the increase of the accelerators, the average size of the F-ZMF microstructures decreased. The F-ZMF shows excellent self-cleaning performance and hydrophilic (water contact angle ≤ 10°) and oleophobic characteristics in the underwater antifouling experiment. Under a dark condition, F-ZMF-4 showed good antibacterial effects against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) with inhibition rates of 99.1% and 99.9%, respectively. This study broadens the application scope of ZnO-based material and provides a novel prospect for the development of self-cleaning super-hydrophilic and oleophobic materials.

Fabrication of highly conductive, flexible, and hydrophobic Kevlar®@Ni-P-B@Cu@CS fabric with excellent self-cleaning performance for electromagnetic interference shielding.

In this work, a simple and cost-effective method was proposed and developed to prepare a novel multilayer-structured Kevlar®@nickel-phosphorus-boron@copper@copper stearate (Kevlar®@Ni-P-B@Cu@CS) composite fabric with high conductivity, high flexibility, high hydrophobicity, and high durability to effectively shield electromagnetic interference (EMI). In this method, an amorphous Ni-P-B alloy nanolayer was initially deposited onto a Kevlar® fabric via electroless plating. Afterward, a crystalline Cu nanolayer was deposited as the second layer via electroplating. Finally, a monolayer of copper stearate was innovatively self-assembled as the outermost protective layer. The Cu deposition was effectively adjusted and designed by controlling the plating current and plating time. The electrical resistance and contact angle of the optimized Kevlar®@Ni-P-B@Cu@CS composite fabric were as low as 3.2 mΩ sq-1 and as high as 115.39°, respectively, indicating that the fabric could withstand bending, tape-off, corrosion, and accelerated environmental tests. The average EMI-shielding efficiency of the durable composite fabric was 93.9 dB in the frequency range of 8.2-12.4 GHz, which was mainly attributed to the absorption loss. Thus, the proposed material configuration has promise for applications in aviation, aerospace, telecommunication, wearable devices, and military industries.

Facile preparation of durable superhydrophobic coating with microstructure self-repairing function by spraying method

Self-healing superhydrophobic coatings have attracted tremendous attention recently, although their practical applications are severely limited by hydrophobic instability and poor structure durability. In this study, a durable superhydrophobic coating was fabricated by a rapid micro/nano structural reconstruction strategy. Carbon nanofibers (CNF) with high aspect ratio were interspersed in fluorosilicone resin (FSR) to construct a uniform network structure. By combining with temperature-responsive carnauba wax (CW) and modified fluororubber (MFR), we obtained a superhydrophobic FSR/CNF/CW/MFR coating with a water contact angle (WCA) of 157 ± 1.2° and water sliding angle (WSA) of 4.5 ± 0.4°. Under the triple synergy of polymer segment migration of FSR, temperature-responsive phase transition of CW, and elastomer rebound repair of MFR, the damaged FSR/CNF/CW/MFR coating surface was rapidly reformed to a new hierarchical micro/nanostructure with short heat treatment (less than 120 s). As a result, for a flat surface, after 1000 abrasion cycles or falling ball impact, a rich micro/nano structure was rapidly reconstructed and superhydrophobic properties were restored. The reconstructed micro/nano multistage structure could effectively capture air, which led to the repaired area exhibiting a charming silver mirror effect and excellent self-cleaning performance. Therefore, this work is expected to provide new insight into the restoration of micro/nanostructures of durable superhydrophobic coatings.

Construction of interconnected nanostructures via linear chains silica for antireflective coatings in solar cell

Solar cells play a pivotal role in increasing the application of solar energy, offering an innovative solution to address the energy crisis. However, the loss of light transmittance through solar cell glass results in the decrease of power conversion efficiency. Base-catalyzed silica antireflection coating can effectively improve light transmittance due to its porous structure, but mechanical fragility limits their applications. To enhance the strength of these coatings, herein we employed two strategies, in-situ and ex-situ catalysis, introducing the acid-catalyzed silica chains to bind the silica nanoparticles and form an interconnected nanostructure. Different combination modes of in/ex-situ silica generate two distinct nanostructures, including nanoparticles tightly connected by short chains or wrapped by long chains. Compared to the ex-situ catalyzed coatings, the in-situ catalyzed coatings have greater porosity, reactivity and mechanical property. When the silica linear chain accounts for 30 %, in-situ catalyzed coatings show an average transmission of more than 96.4 %, representing a 6.5 % improvement over glass plate, and the pencil hardness reaches 3H, meeting the requirements of industrial applications. After the hydrophobic treatment, the water contact angle exceeds 130°, exhibiting excellent self-cleaning performance. It is believed that the facile and scalable in-situ catalyzed AR coatings have great application potential.

Bioinspired Flexible Wearable Sensor with High Self-Cleaning and Antibacterial Performance for Human Motion Sensing.

Flexible wearable strain sensors have shown great potential in monitoring human motion, due to their ability to flexibly fit to multiple surfaces, which can realize the monitoring of human motions and external stimulation. However, the utilization of the sensor in extreme conditions such as low or high temperatures still poses a risk of signal output distortion. Moreover, the continuous usage of the sensor may result in extensive bacterial growth at the interface between the sensor and the skin, posing a threat to human health. Herein, a hydrophobic flexible antibacterial strain sensor (CGP) based on carbon black-PDMS was prepared, inspired by the superhydrophobic surface of a lotus leaf. The CGP sensor demonstrates exceptional sensitivity, with a gauge factor (GF) of 0.467 in the strain range of 0-15% and a fast response time (65.4 ms, 5% strain). Additionally, it exhibits a high conductivity of 1.2 mS cm-1 at -20 °C and 2.0 mS cm-1 at 100 °C, indicating its ability to function effectively even in extreme temperatures. The static water contact angle of CGP measures 121.7°, and self-cleaning experiments have confirmed its excellent self-cleaning performance. Furthermore, the CGP displays distinct response characteristics to movements of human fingers, wrists, and knees, making it an ideal choice for monitoring various joints in the human body. In terms of antibacterial properties, CGP has demonstrated an antibacterial rate of over 99% against E. coli and S. aureus. Possessing high sensitivity, superior electrical conductivity in harsh environments, and super antibacterial capabilities, CGP holds significant potential for applications in human motion monitoring and other fields.

UV-assisted stabilization of superhydrophobic nanofibrous membranes for waterproof, breathable and thermal insulation applications

Polyacrylonitrile (PAN)/polyurethane (PU)/hydrophobic silicon dioxide (SiO2) nanofibrous membranes were prepared by electrospinning combined with a UV-induced stabilization method. The PAN/PU/SiO2 membranes possessed excellent self-cleaning performance because the introduction of SiO2 nanoparticles endowed the nanofibrous membranes with high surface roughness and good hydrophobicity. In addition, SiO2 nanoparticles could also promote the waterproof performance of nanofibrous membranes because hydrophobicity improved and pore size decreased with the increase of SiO2 content. Water vapor transmission rate of the membranes decreased from 10.8 to 9.2 kg m−2 d−1 with increasing of SiO2 concentration because SiO2 nanoparticles could fill the spaces among the adjacent nanofibers. Reflectance to sunlight of the PAN/PU/SiO2 membrane was much higher than that of the PAN/PU membrane, indicating an obvious radiative cooling effect due to loading of SiO2 nanoparticles. This facile fabrication of fluorine-free superhydrophobic membranes provides advantages for potential applications in self-cleaning materials and versatile protective clothing.

Fabrication of superhydrophobic self-cleaning Ni-Co-MoS2/Ni composite coating

This work investigated the parallel magnetically assisted jet electrodeposition of Ni-Co-MoS2/Ni superhydrophobic composite coatings. As a comparison, the effect of the magnetic field on Ni-Co alloy coatings was analyzed. Then, micro/nano MoS2/Ni particles were further added to study the performance of Ni-Co-MoS2/Ni composite coatings under different concentrations of micro/nano particles. Research indicated that the Ni-Co-MoS2/Ni composite coating surface exhibits coral like micro/nano structures, and the micro/nano structures became denser as the concentration of micro/nano particles increased. The superhydrophobic composite coatings were obtained without any chemical modification reagents. The contact angle of the superhydrophobic composite coating was as high as 153.2° and the sliding angle was 8.7° when the amount of micro/nano particles was added at 5 g/L. The coral like micro/nano structures of the composite coating provided additional air cushion to support surface water droplets and exhibited excellent self-cleaning performance. In addition, the composite coating also showed excellent corrosion resistance and wear resistance, which was still relatively intact after friction, only exhibiting few wears on coral like micro/nano structures, it still maintained a good silver mirror effect after friction. This work suggested that parallel magnetically assisted jet electrodeposition could fabricate superhydrophobic composite coatings with excellent performance.

A facile and cost-effective fabrication of robust carbon black-based superhydrophobic coatings on aluminum alloy

Frozen contamination, including ice and frost, on the key surface of systems or facilities, can lead to serious problems and substantial financial losses. Superhydrophobic materials with high water contact angle (CA) and low sliding angle (SA) are potentially effective as anti-icing and self-cleaning materials. Herein, we present an inexpensive and durable superhydrophobic material prepared by combining carbon black (CB) and epoxy resin (EP) with polydimethylsiloxane (PDMS) via facile spraying. The as-prepared superhydrophobic material named PDMS@CB has excellent water repellence, and its water CA and SA can reach 171.5° and 4.6°, respectively. PDMS@CB characteristics are systematically investigated via field-emission scanning electron microscopy, laser scanning confocal microscopy, atomic force microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. PDMS@CB exhibits satisfactory chemical and thermal stability. After being dragged for a length of 800 cm, the CAs remain above 150° and the SAs remain below 10° for PDMS@CB, indicating the excellent durability of the material. Furthermore, the superhydrophobicity of PDMS@CB renders the material outstanding anti-icing and photothermal de-icing characteristics. PDMS@CB also exhibits excellent self-cleaning performance under the pollution caused by the daily liquid contaminants.

Urchin-like fluorinated covalent organic frameworks decorated fabric for effective self-cleaning and versatile oil/water separation

Oil contamination and industrial organic pollutants emission have been a serious problem affecting the ecological and residential environment. Membrane-based separation shows great application prospect due to its low-cost, environmental-friendly and easy operation. Therefore, the development of efficient oil-water separation membranes is highly desirable. Herein, a fabric filter with superwettability was prepared by coating urchin-like fluorinated covalent organic frameworks (COFs) on fabric, which was well utilized in filtering immiscible oil-water mixture and surfactant-stabilized water-in-oil emulsion driven only by gravity for the first time. The as-prepared COF fabric filter (defined as fabric@u-FCOF) possessed many outstanding properties, including superhydrophobicity with the water contact angle of approximately 151.6°, satisfactory resistance for alkaline, acidic and saline environments, as well as superior mechanical durability under harsh conditions. Because of the super-micropore of fabric@u-FCOF and the nanopore in the COF coating, the obtained fabric@u-FCOF exhibited excellent performances in terms of separation efficiency and permeability, in which the oil flux was up to 16964 L·m−1·h−2 and separation efficiency for the mixed o-dichlorobenzene/water was higher than 99.4%. In addition, the fabric@u-FCOF also showed excellent self-cleaning performance due to the micro/nano hierarchical structure of its surface. These excellent properties make it an ideal candidate for applications of oil/water separation and water purification.

Explication of polydopamine modified g-C3N4 as effective additive in PVDF nanocomposite membrane fabrication for enhanced ultrafiltration and self-cleaning performance

Nanocomposite membranes (NCMs) incorporated with nanomaterials have recently received increasing attention, but the preparation of high-performance membranes is still challenging due to the hydrophilicity and self-aggregation of the nanoparticles. In this study, graphite carbon nitride containing nitrogen defects was modified using dopamine (PDA@DCN) for effective alleviation of the agglomeration of nanoparticles resulting in a uniform casting solution. A non-solvent-induced phase separation method was adapted to prepare PVDF NCMs by using PDA@DCN as an effective additive. Superior permeability and selectivity were exhibited by the PDA0.25 @DCN/PVDF2 membrane (where a DA concentration of 0.25 g/100 mL was used in PDA@DCN preparation and 2% PVP was added during the membrane preparation) with the pure water flux of 390 L/(m2·h) and Bovine serum albumin (BSA) rejection of 95.9%. The extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory revealed that the improvement of the flux recovery rate of PDA0.25 @DCN/PVDF2 was due to the decreased attractive interaction for fouling. Ternary phase diagram and viscosity experiments confirmed that the addition of PDA0.25 @DCN accelerated phase inversion rate (as evident from thermodynamics and kinetics) and increased the porosity with smaller average surface pore size, which is expected to have good permeability and selectivity as an ultrafiltration membrane. Moreover, an excellent self-cleaning performance was demonstrated by PDA0.25 @DCN/PVDF2, with a flux recovery rate of 84.5%, simply under visible light irradiation, which indicates its potential for environment-friendly practical application.

A facile fabrication method of wettability modification of TiAl6V4 based on alkali solution treatment: Superhydrophilic, superhydrophobic and slippery surface

The rapid development of nanoscale surface modification technology has led to the development of superhydrophilic, superhydrophobic, and slippery liquid-infused porous surfaces (SLIPS) in recent decades. These surfaces have excellent self-cleaning and anti-contamination performance, and many studies have reported their industrial applications. Industrial and modern medical applications of titanium are rapidly expanding owing to its advantages of chemical stability, high mechanical strength, stable corrosion resistance, and biocompatibility; however, performing surface modification of titanium remains challenging. In this study, superhydrophilic, superhydrophobic, and SLIPS were fabricated on titanium using a simple surface fabrication method, and their wettabilities were analyzed and compared. Furthermore, we succeeded in applying the method used in this study to bulky and complex objects. Chemical and physical analyses were performed to confirm the fabrication, wettability properties, and nanostructures of the modified surfaces. The simple fabrication method presented a significant advancement as there are no limitations in its application to large areas, complex shapes, or mass production, unlike existing titanium wettability modification methods.

Design and performance optimization of self-cleaning coating on decorative UHPC surface

After long-term use, decorative UHPC may adhere to pollutants due to its hydrophilicity, which affects its aesthetics. Due to the smooth and dense exposed surface of UHPC, ordinary self-cleaning coatings have poor adhesion on its surface and are prone to peeling off due to rain wash in the environment, which cannot maintain the self-cleaning performance of UHPC for a long time. In this paper, a modified self-cleaning coating with a double layer structure was designed. The bottom layer is an epoxy resin (ER) adhesive layer to improve the adhesion performance of the coating to UHPC. The surface layer is a polymethylhydrosiloxane (PMHS) modified nano-SiO2 superhydrophobic layer, which satisfies the self-cleaning characteristics while constructing a regular rough superhydrophobic surface on the UHPC surface. The prepared superhydrophobic UHPC showed good self-cleaning performance, with a static water contact angle of 156.5and a sliding angle of only about 2.2. The performance test results show that the double-layer structure design makes the superhydrophobic coating have good wear resistance, water erosion resistance and excellent chemical stability. The surface functional groups, micro-area morphology and roughness were characterized by Fourier transform infrared spectrometer, scanning electron microscopy, optical profiler and atomic force microscopy, respectively. The reasons for the excellent self-cleaning performance and long-term stability of the coating were explained.

PES/Fe3S4@NiO self-cleaning membrane with rapid catalysis for effective emulsion separation and dye degradation

The Fenton membrane is effective in removing organic pollutants from wastewater through the synergy of Fenton catalysis and membrane separation. However, the preparation of a Fenton membrane with excellent self-cleaning performance, catalytic ability, and stability remains a key research direction. Herein, a polyethersulfone (PES)/Fe3S4@NiO membrane was obtained via a non-solvent phase inversion method. The intercalation of photo-Fenton catalytic Fe3S4@NiO into the PES membrane can not only enhance the hydrophilicity but also endow the membrane with photo-Fenton catalytic activity. The separation efficiency of the obtained membrane for multiple oil-in-water emulsions exceeded 98.8%. In addition, the membrane presented excellent self-cleaning performance and stability, the separation efficiency remained high and stable even after 10 cycles of oil-in-water emulsions. Meanwhile, the effective degradation of several organic dyes under visible light was simulated; results showed that the membrane can achieve nearly 100% degradation of methylene blue in 9 min as well as rhodamine B and methyl orange in 3 min, and this membrane maintained high degradation efficiency (>98.7%) even after 5 cycles. Therefore, the results indicate that this PES/Fe3S4@NiO membrane has excellent separation performance and photo-Fenton activity, and the proposed membrane has a potential application scope for efficient emulsion separation and speedy dye degradation.

Stable method for electrodepositing network-like magnesium hydroxide layer with superhydrophobicity and enhanced surface performance under structure direction of xanthan gum/glycerol

Investigation of magnesium hydroxide superhydrophobic layer would significantly improve the application of green and low-cost superhydrophobic materials, for the abundant source, low economic cost, nontoxicity and environment friendliness of magnesium hydroxide. In this work, an obviously developed method which is stable and easy for fabricating network-like magnesium hydroxide superhydrophobic layer on iron substrate has been rendered, simply by cathodic electrodeposition with magnesium nitrate aqueous solution under structure direction of glycerin cross-linked xanthan gum, and subsequent surface modification with 1H,1H,2H,2H-perfluorodecyltriethoxysilane. The preparation process could be carried out at tremendously wide range of bath temperature (from 15 °C to 75 °C), xanthan gum/glycerol dissolving temperature (from room temperature to 100 °C), and storage times (from 0 day to 30 days). The superhydrophobic layer obtained at 35 °C bath temperature with addition of xanthan gum/glycerol dissolved at room temperature and stored for 7 days, shows strong water repellency (160.1° water contact angle, 3.2° sliding angle), and excellent self-cleaning performance. The layer also demonstrates good mechanical property according to cross hatch adhesion and tape peeling test, and owns an inhibition current efficiency as high as 99.98%, taking advantage of its extremely high anti-corrosion resistance (Rct = 2.87 × 105 Ω cm−2, Rf = 1.49 × 109 Ω cm−2).

Biomimetic high water adhesion superhydrophobic surface via UV nanoimprint lithography

Imitating nature and comprehending its workings is a means for human beings to advance the development of functional materials. In this study, UV nanoimprint lithography technology was utilized to successfully replicate the micro-nano hierarchical structure (micro-papillae and nano-wax tube crystals) present on the surface of the natural fresh lotus leaf. A series of UV-curable waterborne polyurethane acrylate (UV-WPUA) surfaces with special wetting and superhydrophobic properties were obtained. The polydimethylsiloxane negative stamp with lotus leaf’s structure was obtained through a stamp replica molding method, and then the UV-WPUA resin covered with the negative stamp was exposed to 172 nm Xe2* excimer and medium-pressure mercury lamps to mimic the micro-nano hierarchical structure of the lotus leaf. The UV-WPUA surfaces displayed high water adhesion superhydrophobic properties, with a water contact angle reaching 160.8° and water adhesive force of 140.0 μN, and exhibiting excellent self-cleaning performance. The results indicate that higher the UV intensity, the more accurately the surface replicates the micro-nano hierarchical structure of the lotus leaf, resulting in larger water contact angle and higher adhesive force. This study paves the way for the advancement of functional surfaces through the simulation of natural materials.