Simple Spray Method Research Articles

Dual-Coating of Fluorinated Polydimethylsiloxane/Fluorinated SiO2 Nanoparticles for Superhydrophobic and High-Efficiency Bacteriostatic Surface.

A simple two-step spray method is used to prepare superhydrophobic and bacteriostatic surfaces, involving dual-coating with polydimethylsiloxane-normal-fluorine (PDMS-NF) or branched-fluorine (PDMS-BF) in combination with fluorinated silica nanoparticles (FSiO2 -NPs) using a spray technique. This approach has the potential to create surfaces with both water-repellent and antimicrobial properties, which could be useful in a variety of applications. It is noteworthy that the dual-coating on cotton fabric exhibited an impressive dual-scale roughness and achieved superhydrophobicity with a water contact angle of 158° and a hysteresis of less than 3°. Additionally, the coating was subjected to an ultra-high concentration of bacteria (109 CFU/mL) and was still able to inhibit more than 80 % of attachment, demonstrating its effectiveness as a bacteriostatic surface.

Sustainable, efficient, and synergistic photocatalytic degradation toward organic dyes and formaldehyde gas via Cu2O NPs@wood

Cuprous oxide (Cu2O) nanoparticles (NPs) was anchored on wood by simple spraying method, then both soft and hard wood has been endowed efficient function photocatalytic degradation toward organic dyes and formaldehyde gas synergistically. The best recycle ability of wood based photocatalyst toward organic pollutants was achieved, which was characterized by photocatalytic degradation efficiency of methylene blue (MB) more than 95% after 100 cycles, and formaldehyde gas over 85% after 60 cycles. Cu2O NPs@wood performed much lower forbidden bandwidth (Eg), which accelerated to generate much more radical of e− and finally promoted the capacity of photocatalytic degradation. The proposed Cu2O NPs@wood catalysts has potential to be applied both in the field of wastewater and air pollution remediation.

Multi-functional and durable anti-corrosion coatings with hydrophobic, freeze time retardation and photothermal properties by means of a simple spraying method

In this study, a composite material consisting of perfluorinated quaternary silane-modified graphene oxide and modified CeO2 nanoparticles was prepared, and a hydrophobic, corrosion-resistant, self-cleaning and anti-icing composite coating was prepared by combining the composite material with polyphenylene sulfide (PPS) through high-temperature curing in a simple spraying method for the protection of iron sheets. The results show that the composite coating has excellent corrosion resistance, strong mechanical properties and certain photothermal properties. When the content of perfluorinated quaternary silane modified CeO2 nanoparticles with graphene oxide (P-GKC) was 10 wt%, the composite coating had a water contact angle of 145.6 ± 3° and a sliding angle of 5 ± 1°, with good hydrophobicity and low surface energy. Meanwhile, the hydrophobic modification of perfluoroquaternary silanes reduced the surface energy of the particles in the composite coatings and greatly improved the hydrophobicity. Surface temperature and laser irradiation tests of the composite coatings showed that the photothermal properties of the composite coatings were better than those of the single PPS and graphene oxide (GO) coatings, with good photothermal cycling stability.The Tafel curves and the EIS results showed that the PPS/10 wt% P-GKC composite coatings had the best corrosion resistance, with a corrosion current density of 5.01 × 10−9A cm−2. After 200 h of salt spray test in 3.5 % NaCl environment, the PPS/10 wt% P-GKC composite coating still has good substrate protection effect, which provides a practical basis for the research of composite coating anticorrosion.

Quantitative generation of ROS and their effective photocatalytic antibacterial activity of high-intensity universal P25 network films: The role of ROS

Reactive oxygen species (ROS) generation and utilization were the foundation for the photocatalytic degradation of pollutants or anti-bactericidal effect. Especially for solid-phase film photocatalysis, a simple and firm immobilization method that ensured exposure of active sites and effective production of ROS was the key. Presently, a P25 network films was achieved using water-based polyurethane acrylate (WPUA) as adhesive through a simple and convenient direct spraying method. The physical and chemical properties of the P25 network films were characterized and the results showed that P25 was firmly adhered on the metal wire mesh and fully exposed the active sites of P25. Dynamic generation of ROS on 304SS@P25 films interface was systematically investigated. The concentration of hydroxyl radicals (•OH), superoxide radicals (O2•−) and hydrogen peroxide (H2O2) on 10 cm × 3 cm 304SS@P25 after 2 h of UV irradiation were 9.4 ± 0.3 × 10−9 M, 7.6 ± 0.3 × 10−9 M, and 11.7 ± 0.9 × 10−6 M, respectively, which was similar with ROS generation of P25 nanoparticle suspensions. In addition, the ROS-mediated antibacterial effect of 304SS@P25 films was investigated, and a linear correlation was found between the concentration of ROS generated and the E. coli sterilization rate. Furthermore, 304SS@P25 films could be successfully applied in the air sterilizer to exhibit a good bactericidal effect. This ROS-oriented photocatalyst immobilization method opened up a new pathway for water and air purification and provided a new strategy in the field of photocatalytic antibacterial technology.

One-step fabrication of a robust and transparent superhydrophobic self-cleaning coating using a hydrophobic binder at room temperature: A combined experimental and molecular dynamics simulation study

Superhydrophobic coatings, as a type of functionalized coatings, are extensively studied in the field of self-cleaning. However, obtaining superhydrophobic coatings with excellent transparency and robustness through a simple fabrication process remains a challenge. In this work, we synthesize a hydrophobic binder using hydroxyl-terminated polydimethylsiloxane (HTPDMS) as the main raw material. We also hydrophobically modify SiO2 nanoparticles as low surface energy substances. The superhydrophobic coating is then obtained by a simple spraying method and cured at room temperature. The combination of the binder and nanoparticles in the right amount forms a rough structure that is able to combine transparency and superhydrophobicity, resulting in a coating with a light transmission of about 88 % and a contact angle of 162°. The presence of PDMS component in the binder enhances the chemical durability and mechanical robustness of the superhydrophobic coating. The coating is not only self-cleaning but also suitable for a wide range of substrates. Furthermore, the kinetic and energetic analysis of the solid-liquid interface using molecular dynamics simulation provides theoretical support for the superhydrophobicity of the coating at a microscopic level.

P(MA-AMPS)/PVA@SiO2 hybrid hydrogel coated stainless steel mesh for effective separation of stabilized oil-in-water emulsions under gravity

The superhydrophilic/underwater superhydrophobic membrane offers unique advantages in effectively separating oily wastewater. However, the development of membrane materials that can efficiently separate emulsions only under gravity is still a challenge. A crosslinked network copolymer P(MA-AMPS) was synthesized by radical polymerization of N, n-methylenebisacrylamide (MBA), methacrylamide (MA) and 2-acrylamide-2-methylpropanesulfonic acid (AMPS) initiated by potassium persulfate. Then polyvinyl alcohol (PVA) and nano-SiO2 were inserted to the crosslinked polymer system in order to prepare a P(MA-AMPS)/PVA@SiO2 hybrid hydrogel. The hybrid hydrogel can be sprayed on the surface of stainless steel mesh (SSM) by a simple spraying method, so as to achieve superhydrophilicity/underwater superoleophobicity. The oil-water emulsion permeation flux reached more than 352.94 L·m−2·h−1, while xhibiting a more than 99.5 % separation efficiency under gravity. The anti-fouling tests demonstrated that the membrane exhibited outstanding anti-fouling performance. Moreover, the combination of stable semi-interpenetrating networks and nanoparticles made the membrane exhibit excellent stability and durable separation ability in complex physicochemical environments.

Fabrication of a fluorine-free photocatalytic superhydrophobic coating and its long-lasting anticorrosion and excellent antibacterial abilities

Superhydrophobic multifunctional coatings have wide application prospects in construction, shipping, transportation equipment and aerospace etc. In this paper, a fluorine-free photocatalytic superhydrophobic coating with long-lasting anticorrosion performance and excellent antibacterial ability has been developed on various substrates by a simple spraying method. The coating is mainly composed of epoxy resin (EP), polydimethylsiloxane (PDMS) and hydrophobically modified micron ZnO (m-ZnO) and nano ZnO (n-ZnO). The coating maintains excellent wettability to various common liquids, and the water contact angle (WCA) and sliding angle (SA) of coating are 162.8° and 3°, respectively. The synergistic effect of the air layers and the coating denseness endows coating with excellent corrosion inhibition efficiency (ηp > 99.9 %) in 3.5 wt% NaCl solution and neutral salt spray tests for 30 days. The photocatalytic activity and superhydrophobicity endow coating with bactericidal activity and antibacterial adhesion properties, thus providing the coating with excellent antibacterial ability in dynamic or static liquid environment. Furthermore, the coating can withstand chemical erosion, ultraviolet radiation and mechanical durability tests such as knife scraping, tape peeling and sandpaper wear cycles. This large-scale fabrication, environmentally benign, low cost and high performance coating has potential practical applications in a wider range of fields.

Implementation of Enhanced Spray Routing Protocol for VDTN On Surabaya Smart City Scenario

The application of smart-city, which promises better city management in helping to improve people's quality of life, is still inhibited due to the high cost of infrastructure investment. In several Smart Cities, it takes at least $ 30 - 40 billion to convert a conventional town into a smart city, including for data collection infrastructure. Alternatively, low-power wide-area networks (LPWANs) could be considered, but they need more bandwidth to serve data transmission in a smart city. Vehicle Delay Tolerant Network (VDTN) is one part of DTN that employs vehicles as a communication infrastructure that allows communication in challenging conditions and could make it an alternative network for Data Collection in a Smart City. This paper proposes a Surabaya Smart City scenario with VDTN as data collection. The scenario consists of 40 wireless sensors and 50 to 200 vehicles (car and bus) with five Road Side Units that forward data from the sensor to the monitoring server. Furthermore, to increase the VDTN performance, we improve our proposed routing protocol, Spray and Hop Distance (SNHD), with two sprays method (Adaptive and Simple) and data collection support from multiple sources and destinations. The evaluation was carried out using a simulation-based comparison with an increase in the number of vehicles to determine the impact of vehicle density on data collection performance in terms of delivery probability, latency average, and overhead ratio. Based on the simulation results, the simple spray method in SNHD and A-SNHD outperformed the well-known VDTN routing protocol, i.e., Epidemic and Spray and Wait. Furthermore, when the number of cars increases from 50 to 200, the performance of VDTN does not increase significantly as the density of the network increases. It means that VDTN only requires a small number of vehicles to be used as a low-cost alternative network for smart cities.
 

Towards a high-performance anode for zinc metal batteries: A tri-functional nitrogen-defective graphitic carbon nitride material for anode protection

As an important potential candidate for large-scale energy storage, rechargeable zinc metal batteries have become a research hotspot. Zn metal anodes are an extremely crucial component of rechargeable Zn metal batteries. However, the Zn dendrites, the evolution of hydrogen and side reactions on the surface of the Zn metal anodes severely hinder its commercial use. Here, we report a modified Zn metal anode with a layer of nitrogen-defective graphitic carbon nitride (NDCN) nanosheets coated onto a commercial Zn foil by a simple spraying method. The NDCN coating on the anode’s surface not only provides zincophilic sites, but also drives the deposition of zinc with a particular crystallographic orientation. At the same time, the formation of zinc dendrites and the evolution of hydrogen were suppressed, which enhanced the reversibility of the anode. Thus, the symmetric cells with the NDCN-protected zinc foil (NDCN@Zn) electrodes remained stable for 2000 h at a current density of 5 mA cm−2. More importantly, the long-term cycling performance of the full cell tested at 1 A g−1 retained approximately 88 % of its capacity even after 2300 cycles. This simple but effective method will provide a reference for future studies on protecting the anodes of zinc metal batteries.

Thermodynamic and kinetic analyses of Janus membrane scaling in membrane distillation for zero liquid discharge engineering

Scaling phenomena are the principal obstacle to the factual application of membrane distillation (MD). In this study, we fabricated a Janus membrane composed of a commercial polytetrafluoroethylene substrate, a superhydrophobic surface layer, and a hydrophilic reverse side coated by MXene nanosheets via a simple spraying method. The virgin and modified membranes were carried out and compared in zero liquid discharge (ZLD) MD experiments. MD flux analysis showed that all the membranes experienced severe flux decline during the ZLD process. Saturation index, Gibbs free energy and nucleation energy barrier were calculated to explain the observed difference in scaling behavior. Screenage assessment of the homogeneous nucleation and heterogeneous nucleation showed that the severe scaling developed from some small clusters of the new phase, wherein the thermodynamic energy barrier played a critical role in determining the anti-scaling behavior for these unsmooth surfaces. Model analysis and data fitting were used to conclude the kinetic behavior of the virgin and modified membranes in the ZLD engineering. Finally, we evaluated the reversible and irreversible scaling after twice washing. Therefore, this study may provide instructive insights to design novel anti-fouling membranes and promote practical applications such as industrial brine treatment and ZLD engineering.

Construction of tannic acid-Fe complex coated PVDF membrane via simple spraying method for oil/water emulsion separation

Here, a polyvinylidene difluoride composite membrane (PVDF@TA–Fe membrane) was prepared via the repeated spraying of tannic acid (TA) and Fe3+ to form a TA–Fe complex on the hydrophobic PVDF membrane, which endows the membrane surface superhydrophilicity. The effects of the number of sprays on the surface wettability and emulsion separation capacity of membrane were systematically investigated. It was found that the TA-Fe(III)-complex network formed on the membrane significantly increased the hydrophilicity of the membrane, and the PVDF@TA–Fe membrane was found to exhibit superhydrophilicity/underwater superoleophobicity. The PVDF@TA–Fe membrane was found to exhibit good separation efficiencies (above 99%) and high fluxes (1189.1–2310.0 L m−2 h −1 bar−1) when used to separate oil and water in various oil/water emulsions. The repeated separation experiments show that the membrane has a good antifouling performance and maintains a good oil/water separation performance after more than 10 cycles. The present work is of great importance to the large-scale preparation of superhydrophilic membranes and treatment of oily wastewater.

Ratiometric Luminescent Thermometer Based on the Lanthanide Metal–Organic Frameworks by Thermal Curing

The high-performance optical thermometer probes are of great significance in diverse areas; lanthanide metal-organic frameworks (Ln-MOFs) are a promising candidate for luminescence temperature sensing owing to their unique luminescence properties. However, Ln-MOFs have poor maneuverability and stability in complex environments due to the crystallization properties, which then hinder their application scope. In this work, the Tb-MOFs@TGIC composite was successfully prepared using simple covalent crosslinking through uncoordinated -NH2 or COOH on Tb-MOFs reacting with the epoxy groups on TGIC {Tb-MOFs = [Tb2(atpt)3(phen)2(H2O)]n; H2atpt = 2-aminoterephthalic acid; phen = 1,10-phenanthroline monohydrate}. After curing, the fluorescence properties, quantum yield, lifetime, and thermal stability of Tb-MOFs@TGIC were remarkably enhanced. Meanwhile, the obtained Tb-MOFs@TGIC composites exhibit excellent temperature sensing properties in the low-temperature (Sr = 6.17% K-1 at 237 K), physiological temperature (Sr = 4.86% K-1 at 323 K), or high-temperature range (Sr = 3.88% K-1 at 393 K) with high sensitivity. In the temperature sensing process, the sensing mode of single emission changed into double emission for ratiometric thermometry owing to the back energy transfer (BenT) from Tb-MOFs to TGIC linkers, and the BenT process enhanced with the increase of temperature, which further improved the accuracy and sensitivity of temperature sensing. Most notably, the temperature-sensing Tb-MOFs@TGIC can be easily coated on the surface of polyimide (PI), glass plate, silicon pellet (SI), and poly(tetrafluoroethylene) plate (PTFE) substrates by a simple spraying method, which also exhibited an excellent sensing property, making it applicable for a wider T range measurement. This is the first example of a postsynthetic Ln-MOF hybrid thermometer operative over a wide temperature range including the physiological and high temperature based on back energy transfer.

Effect of micro-nano structure on anti-frost and defrost performance of the superhydrophobic fin surfaces

In order to study the effect of nanostructures on micro-nano structures on the frost suppression and defrosting performance of the superhydrophobic fin surface of the heat pump, a simple spray method was used to prepare the surfaces with the same static contact angle and rolling angle but different micro-nano structures. The research shows that the frost inhibition ability of superhydrophobic surface can be effectively improved with the increase of the density of nanostructures. In the condensation process, compared with the surface of micro-nano structure with low density nanostructures, the condensed droplets on the surface of high-density nanostructures have the characteristics of high renewal rate, small average size and low coverage. When condensing for 32 min, the number of condensation droplets merging, bouncing and sliding on the surface of nanostructure is 47.5% higher than that on the surface of micro-nano structure, and the area coverage of droplets is 25.46% lower than that on the surface of micro-nano structure. In the frosting experiment, superhydrophobic surface with the micro-nano structure lost its anti-frosting performance due to the Wenzel-state of condensate droplets, and the frost coverage rate reached 100% within 5 min. However, the frost coverage rate of the nanostructured surface only reached 4.6% in 10 min and reached full coverage in 95 min. It can be seen that the condensate droplet behaviors and frost suppression performance of the superhydrophobic surface are more sensitive to the surface nanostructure. However, the defrosting process is not sensitive enough to the nanostructures of the superhydrophobic surface. This standard provides the idea for the simple preparation of anti-frost superhydrophobic surface on the air-source heat pump fins.

Development of Cellulose-Reinforced Polyurethane Coatings: A Novel Eco-Friendly Approach for Wind Turbine Blade Protection

Wind energy is considered a clean energy source and is predicted to be one of the primary sources of electricity. However, leading-edge erosion of wind turbine blades due to impacts from rain drops, solid particles, hailstones, bird fouling, ice, etc., is a major concern for the wind energy sector that reduces annual energy production. Therefore, leading-edge protection of turbine blades has been an important topic of research and development in the last 20 years. Further, there are critical issues related to the amount of waste produced, including glass fiber, carbon fiber, and various harmful volatile organic compounds in turbine fabrication and their end-of-life phases. Hence, it is vital to use eco-friendly, solvent-free materials and to extend blade life to make wind energy a perfect clean energy source. In this study, cellulose microparticles (CMP) and cellulose microfibers (CMF) have been used as fillers to reinforce water-based polyurethane (PU) coatings developed on glass fiber reinforced polymer (GFRP) substrates by a simple spray method for the first time. Field emission scanning electron microscopy images show the agglomerated particles of CMP and fiber-like morphology of CMF. Fourier transform infrared spectra of CMP, CMF, and related coatings exhibit associated C–H, C=O, and N–H absorption bands of cellulose and polyurethane. Thermal gravimetric analysis shows that CMP is stable up to 285 °C, whereas CMF degradation is observed at 243 °C. X-ray photoelectron spectroscopy of C 1s and O 1s core levels of CMP, CMF and related coatings show C–C/C–H, C–O, C–OH, and O–C=O bonds associated with cellulose structure. The solid particle erosion resistance properties of the coatings have been evaluated with different concentrations of CMP and CMF at impact angles of 30° and 90°, and all of the coatings are observed to outperform the PU and bare GFRP substrates. Three-dimensional (3D) profiles of erosion scans confirm the shape of erosion scars, and 2D profiles have been used to calculate volume loss due to erosion. CMP-reinforced PU coating with 5 wt.% filler concentration and CMF-reinforced PU coating with 2 wt.% concentration are found to be the best-performing coatings against solid particle erosion. Nanoindentation studies have been performed to establish a relation between H3/E2 and the average erosion rate of the coatings.

Robust superhydrophobic materials with outstanding durability fabricated by epoxy adhesive-assisted facile spray method

Superhydrophobic materials are promising next-generation waterproof materials due to their excellent self-cleaning, antifouling and additional capabilities. Herein, the superhydrophobic materials with excellent comprehensive performance were developed via a simple, low-cost, environmental, and scalable spray method with epoxy adhesive assistance. The epoxy adhesive enhanced the adhesion strength between spray coating and substrates significantly. Consequently, various properties of superhydrophobic coatings were improved greatly. The as-prepared superhydrophobic surfaces exhibited excellent mechanical durability. The water contact angle maintained unchanged basically and sliding angle only increased slightly even though sandpaper abrasion distance had extended to 2100 cm or tape-peeling test had reached 30 cycles. Moreover, the strong water repellence retained even after 72 h immersion in strong acid/alkali, 1 h treatment upon 280 °C, and 7 days exposure under 254 nm UV light. These indicated that the obtained superhydrophobic materials exhibited outstanding acid, alkali, high temperature, and UV light resistance and stability. Besides, the superhydrophobic materials demonstrated excellent self-cleaning and anti-icing performance. So the synthetic superhydrophobic materials were expected to have a wide range of applications in the industrial production and daily life. More importantly, they could be applied in a variety of harsh environments for long periods of time.

Gallic Acid-Reduced Graphene Oxide Deposited with Carbon Nanotubes for Transparent Film Heaters

The flexible transparent film heater described in this research was based on graphene, carbon nanotubes (CNTs), and polyethylene terephthalate (PET). Natural polyphenols gallic acid (GA) was chosen as the “green” reducing agent of graphene oxide (GO) to prepare the GA-functionalized GO (GGO). Then, the GGO nanosheets were introduced into the CNT network, and the GGO/CNT-PET composite films were successfully prepared by a simple spraying method. This type of transparent conductive film (TCF) possesses an excellent optoelectronic performance (Rs = 49.1 Ω/sq., T = ca. 80% at 550 nm) and a very low RMS roughness (approximately 6.89 nm). The sheet resistance of the films changed slightly after the 1000 bending cycles and 100 h of air exposure time, which indicated that the film has good mechanical properties and environmental stability. The composite TCFs were further applied to fabricate transparent film heaters (TFHs) and showed excellent Joule heating performance, fast response speed, good cycling stability, long-term stability, and controllable operating temperature (the power density of the TFHs shows an approximate linear behavior), which satisfy the requirements of TFHs in practical applications, such as safe voltage and temperature in wearable devices, the stable controlling temperature in smart windows, fast heating in defoggers, and so on.

Controlled manufacturing of black and white flower-like dendritic micropattern tags for product unclonable security identification

Anti-counterfeiting tags with physical unclonable functions (PUFs) are critical for ensuring the security of products. In general, PUFs exhibit unique random physical patterns as a result of a stochastic minutiae that generates a large number of robust tags. In the current study, a novel flower-like dendritic micropattern security tag is created in rapid batch production by a simple one-step spray method and a comprehensive examination of the entire security identification system is conducted, from signage to literacy. A silicate condensation reaction was controlled to tune the morphology, resulting in six-class micropatterns with regular geometry. Additionally, the recognition feature of tags was derived directly from the shape contour and distribution characteristics of the pattern. Thus, the micropatterns have both stochastic minutiae and rule-based aspects. The unpredictability of the micropatterns’ size and position distribution contributes to the tags’ high robustness and the structural regularity has potential utility in error correction schemes. The article also discusses the mechanism involved in the formation and evolution of six-class patterns and conducts a systematic analysis of the mathematical foundation of the uniqueness of micropatterns. The experimental statistics indicate that, by appropriately limiting the deviation of the curing parameters and the image capture position, the production and identification of tags remain controllable and stable. Additionally, the tag identification exhibits significant intraclass correlation and interclass uncorrelation, indicating that they meet the requirements for high robustness of anti-counterfeiting tags. These tags have significant potential for application in security management of customized products, high-value goods and forensic purposes.

Self-healing and wear resistance stable superhydrophobic composite coating with electrothermal and photothermal effects for anti-icing

Superhydrophobic material has great potential applications in the field of anti-icing due to its special wettability. However, the poor wear resistance of the material has restricted its practical applications. Based on this, a simple two-step spray method was used to prepare a self-healing and robust superhydrophobic coating with excellent photothermal/electrothermal effect for anti-icing using epoxy modified ethylene octene copolymer (POEG) resin as the substrate layer and the fluorinated carbon black as the top coating. Results showed that the obtained composite coating showed multi-level rough structure and possessed excellent superhydrophobicity toward water droplets with different pH. Meanwhile, the composite coating could resist abrasion and kept superhydropbobicity even 250 cycles abrasion test with a water contact angle higher than 150o. When the surface was subjected to the intense abrasion, the rough structure and the superhydrophobic property of the surface were destroyed. However, it could be restored by the abrasion of the rougher surface. In addition, the scratches on the surface could be completely repaired by the heat treatment, indicating the good self-healing performance of the composite coating. Due to the existence of the carbon black particles, the superhydrophobic coating had good photothermal/electrothermal effects, which endowed the surface with excellent anti-icing performance of removing the icing under the conditions of electrothermal and light. This paper provides a simple and convenient way to prepare functional self-healing superhydrophobic coating, and a new idea for the preparation of anti-icing coating.

A durable superhydrophobic polyphenylene sulfide composite coating with high corrosion resistance and good self-cleaning ability

In this work, a durable polyphenylene sulfide (PPS) composite superhydrophobic coating was prepared using a simple spraying method. By adding GO-ZrO2 composite particles to build micro/nanostructures on the surface of the coating, combined with the low surface energy of stearic acid, a GO-ZrO2/PPS composite superhydrophobic coating with high water contact angle of 153° ± 1° and low sliding angle of 4° ± 1° was finally obtained. The coating exhibits good stability and maintains a clean surface even after repeatedly pulling in muddy water for 100 times. In addition, the coating has good wear and corrosion resistance with a corrosion rate of 3.07 × 10−8 g/m2h. Therefore, this superhydrophobic composite coating with durability, wear resistance, and corrosion resistance can provide promising applications in the field of anti-corrosion.

Fast and Multifunctional Optically‐Driven Actuators based on Stable, Efficient, and Superhydrophobic Photothermal Paper Films

AbstractRemotely controlled self‐propelled optically‐driven actuators are increasingly attractive for sensing and robotic applications. However, complexities in material synthesis, multifunctionality, dynamic response, and the response rate limit their use for wide‐ranging application. This work uses a simple and efficient spraying method to prepare optically‐driven actuators based on TiN@PDMS‐PVDF (TiN@polydimethylsiloxane‐polyvinylidene difluoride) papers. The actuator exhibits stable superhydrophobicity for photothermal heating and corrosive solutions with a contact angle and sliding angle of 169.9° and 2.3°, respectively. The superhydrophobic actuators exhibit an efficient photothermal conversion aided by a very high optical absorption of the material approaching 97%. The optically‐driven actuator based on the TiN@PDMS‐PVDF paper exhibit a fast response and movement on the water surface. A 1.5 W cm−2 laser‐driven actuator yields a response time of 0.84 s, with its linear velocity approaching 10.1 mm s−1. The multifunctional optical‐driven actuators can easily perform operations such as linear and rotational motion optically engineered to avoid obstacles, transport cargo, and clean oil over a water surface. These fast, multifunctional, superhydrophobic actuators have bright prospects in many fields, such as bioengineering, environmental protection, and micro‐robots.