Nature-Inspired Hierarchical Protrusion Structure Construction for Washable and Wear-Resistant Superhydrophobic Textiles with Self-Cleaning Ability

Janus Flexible Device with Microcone Channels for Sampling and Analysis of Biological Microfluidics

Controlling the spontaneous directional transport of droplets plays an important role in the application of microchemical reactions and microdroplet detection. Although the relevant technologies have been widely studied, the existing spontaneous droplet transport strategies still face problems of complex structure, single function, and poor flexibility. Inspired by the spontaneous droplet transport strategy in nature, an asymmetric wettability surface with microcone channels (AWS-MC) is prepared on a flexible fabric by combining surface modification and femtosecond laser manufacturing technology. On this surface, the capillary force and Laplace pressure induced by the wettability gradient and the geometric structure gradient drive the droplet transport from the hydrophobic surface to the hydrophilic surface. Notably, droplets in adjacent hydrophilic regions do not exchange substances even if the gap in the hydrophilic region is only 1 mm, which provides an ideal platform for numerous detections by a single drop. The droplet transport strategy does not require external energy and can adapt to the manipulation of various droplet types. Application of this surface in the blood of organisms is demonstrated. This work provides an effective method for microdroplet-directed self-transport and microdroplet detection.

Fast Solution Blow Spinning of Lotus-Leaf-Inspired SiO2 Nanofiber Sponge for High Efficiency Purification

Massive production of SiO2 nanofibers with both high durability and exceptional performance remains a significant challenge. Herein, a novel approach was introduced to achieve the massive production of SiO2 nanofibers with lotus-leaf-inspired surfaces by combining solution blowing spinning (SBS) and the polymer-derived ceramics method. Based on the SBS technique, three types of precursor nanofiber products were fast spined with methyl silsesquioxane polymer and polymethyl hydrogen siloxane employed as Si sources. The flow rate of the SBS spined Si-based ceramic nanofibers was enhanced to 20 mL·h-1. Furthermore, through the integration of hydrophobic-oleophilic SiO2 nanoparticles into the precursor solution, SiO2 nanofibers with lotus-leaf nanoprotrusion surfaces were fabricated. Nanoparticle-decorated SiO2 fibers demonstrated excellent hydrophobicity (138.3°), compression resilience (∼60%), proficiency in organic pollutant adsorption, high-temperature resistance (∼1100 °C), and outstanding thermal insulation properties (thermal conductivity of 0.0165 W·(m·K)-1).

Hydrophobicity and Improved Corrosion Resistance of Weathering Steel via a Facile Sol-Gel Process with a Natural Rust Film

Weathering steel, which has a protective corrosion product film, is widely used in various construction and landscaping applications. However, it causes metal contamination in the receiving ecosystem via corrosion-induced metal dissolution and rust runoff. Traditional corrosion prevention methods, such as surface coating, also suffer from environmental pollution and high maintenance costs. In this study, we propose a novel method to make the rust film hydrophobic to prevent corrosion while retaining its original appearance. The crystalline rust is used as a natural skeleton, and nano-SiO2 particles are synthesized in situ on it by a facile sol-gel method. The microscopic analysis shows that the flower-like rust flakes provide a primary structure (micrometric scales) and the nano-SiO2 particles form a secondary structure (nanoscale bumps), which is the essential micronanostructure for forming a hydrophobic surface. The as-synthesized film shows strong corrosion resistance, with the corrosion current density being 4 orders of magnitude lower than that of the samples without hydrophobicity. The hydrophobic surface not only prevents corrosive substances from penetrating into the rust layer but also reduces the risk of contamination through its self-cleaning properties. Therefore, the weathering steel with a hydrophobic rust film can be more stable and environmentally friendly for multiscenario applications.

Stearic Acid and CeO2 Nanoparticles Co-functionalized Cotton Fabric with Enhanced UV-Block, Self-Cleaning, Water-Repellent, and Antibacterial Properties

Superhydrophobic cotton fabrics with multifunctional features are highly desired in domestic and outdoor applications. However, the short coating longevity and hazardous reagents significantly reduce their commercial-scale applications. Herein, we introduce CeO2 nanoparticles and stearic acid (SA) to develop a fluorine-free, durable superhydrophobic cotton fabric that mimics the lotus effect. The pristine cotton fabric is treated with APTES-functionalized CeO2 nanoparticles by immersion followed by a dip and drying treatment with a 2% myristic acid solution. This sequential process creates a stable superhydrophobic cotton fabric (SA/CeO2-cotton fabric) with a water contact angle of 158° and a water sliding angle of 5°. The results are attributed to the combined effect of CeO2 nanoparticles and stearic acid that enhances surface roughness and reduces surface sorption energy. APTES facilitates the durable attachment of CeO2 nanoparticles and stearic acid to the cotton fabric. The modified cotton fabric is characterized by advanced analytical tools, demonstrating enhanced superhydrophobicity, self-cleaning, and antiwater absorption properties. Additionally, it exhibits remarkable UV-blocking (UPF 542) and antibacterial properties. The designed superhydrophobic cotton fabric unveils good mechanical, thermal, and chemical durability. The proposed strategy is simple, green, and economical and can be used commercially for functional fabric preparation.

Recent Advances in Superhydrophobic and Antibacterial Cellulose-Based Fibers and Fabrics: Bio-inspiration, Strategies, and Applications

Cellulose-based fabrics are ubiquitous in our daily lives. They are the preferred choice for bedding materials, active sportswear, and next-to-skin apparels. However, the hydrophilic and polysaccharide characteristics of cellulose materials make them vulnerable to bacterial attack and pathogen infection. The design of antibacterial cellulose fabrics has been a long-term and on-going effort. Fabrication strategies based on the construction of surface micro-/nanostructure, chemical modification, and the application of antibacterial agents have been extensively investigated by many research groups worldwide. This review systematically discusses recent research on super-hydrophobic and antibacterial cellulose fabrics, focusing on morphology construction and surface modification. First, natural surfaces showing liquid-repellent and antibacterial properties are introduced and the mechanisms behind are explained. Then, the strategies for fabricating super-hydrophobic cellulose fabrics are summarized, and the contribution of the liquid-repellent function to reducing the adhesion of live bacteria and removing dead bacteria is elucidated. Representative studies on cellulose fabrics functionalized with super-hydrophobic and antibacterial properties are discussed in detail, and their potential applications are also introduced. Finally, the challenges in achieving super-hydrophobic antibacterial cellulose fabrics are discussed, and the future research direction in this area is proposed.

Graphical Abstract

The figure summarizes the natural surfaces and the main fabrication strategies of superhydrophobic antibacterial cellulose fabrics and their potential applications.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42765-023-00297-1.

Skin-Interfaced Superhydrophobic Insensible Sweat Sensors for Evaluating Body Thermoregulation and Skin Barrier Functions

Monitoring sweat rate is vital for estimating sweat loss and accurately measuring biomarkers of interest. Although various optical or electrical sensors have been developed to monitor the sensible sweat rate, the quantification of the insensible sweat rate that is directly related to body thermoregulation and skin barrier functions still remains a challenge. This work introduces a superhydrophobic sweat sensor based on a polyacrylate sodium/MXene composite sandwiched between two superhydrophobic textile layers to continuously measure sweat vapor from insensible sweat with high sensitivity and rapid response. The superhydrophobic textile on a holey thin substrate with reduced stiffness and excellent breathability allows the permeation of sweat vapor, while preventing the sensor from being affected by the external water droplets and internal sensible sweat. Integrating the insensible sweat sensor with a flexible wireless communication and powering module further yields a standalone sensing system to continuously monitor insensible sweat rates at different body locations for diverse application scenarios. Proof-of-concept demonstrations on human subjects showcase the feasibility to continuously evaluate the body's thermoregulation and skin barrier functions for the assessment of thermal comfort, disease conditions, and nervous system activity. The results presented in this work also provide a low-cost device platform to detect other health-relevant biomarkers in the sweat (vapor) as the next-generation sweat sensor for smart healthcare and personalized medicine.

Fabrication of Highly Efficient Flame-Retardant and Fluorine-Free Superhydrophobic Cotton Fabric by Constructing Multielement-Containing POSS@ZIF-67@PDMS Micro-Nano Hierarchical Coatings

The facile construction of a cotton fabric with excellent flame-retardant and water-proof abilities is of great interest for multitask requirements. Herein, a nonfluorine, highly efficient, and cost-effective multifunctional cotton fabric was fabricated via sequentially depositing a novel multielement-containing flame-retardant phosphorylated octa-aminopropyl POSS (PPA-POSS) and a fluorine-free superhydrophobic coating of zeolitic imidazolate framework-67@poly(dimethylsiloxane) (ZIF-67@PDMS). Influences of the PPA-POSS concentration and ZIF-67@PDMS formula on the fire retardancy and water repellency of treated cotton were systematically investigated. The optimized flame-retardant sample CTF3 with 6.2 wt % PPA-POSS exhibited a high limiting oxygen index (LOI) of 34% and self-extinguishing ability. CTF3 was further modified with a properly formulated superhydrophobic ZIF-67@PDMS coating. CTF3-PHB2 displayed enhanced thermal stability, flame retardancy, and outstanding superhydrophobicity. Thermogravimetric analysis (TGA) results demonstrated that CTF3-PHB2 presented a high char residue of 35.9%, which was 220.5% higher than that of the control cotton (11.2%). More importantly, the heat release rate (HRR), total heat release (THR), and average effective heat of combustion (av-EHC) values of CTF3-PHB2 were significantly reduced by 51.4, 56.2, and 68.4%, respectively, compared with those of a pure cotton fabric. Moreover, CTF3-PHB2 showed superhydrophobicity (WCA > 159.3°) and good mechanical abrasion resistance. In addition, CTF3-PHB2 also showed protective abilities such as antifouling, self-cleaning, and water/oil separation performances even for strong acid/alkali mixtures. Thereby, it is believed that the PPA-POSS@ZIF-67@PDMS coating is promising for application in multifunctional textile materials.

Construction of Durable Self-Cleaning PDMS Film on Polyester Fabric Surface

The superhydrophobic surface can be prepared by two methods; one is by reducing the surface energy, and the other is by constructing a micro-nano rough structure. To achieve high superhydrophobic performance in terms of durability, the firm combination of hydrophobic coating and substrate is particularly important. Here, we use polydimethylsiloxane (PDMS) as a low surface energy monomer, water-borne polyurethane (WPU) as a dispersing aid, and use high-power ultrasound to disperse PDMS in water to make emulsion. The polyester matrix is etched by atmospheric plasma, dipped in PDMS emulsion, dried, and finally baked to induce PDMS on the surface of polyester fiber to cross-link into film. A series of tests on the self-cleaning polyester fabric prepared by this method show that when the concentration of PDMS is 8 g/L and the mass ratio of PDMS to WPU is 20:1, the water contact angle (WCA) reaches the maximum value of 148.2°, which decreases to 141.5° after 200 times of washing and 138.6° after 5000 times of rubbing. Before and after PDMS coating, the tensile strength of polyester fabric increases from 489.4 N to 536.4 N, and the water vapor transmission decreases from 13,535.7 g/(m²·d) to 12,224.3 g/(m²·d). This research is helpful to the large-scale production of self-cleaning polyester fabric. In the future, on the basis of this research, we will add functional powder to endow self-cleaning polyester fabric with higher hydrophobicity and other properties.

Recent advances in eco-friendly fabrics with special wettability for oil/water separation

Considering the serious damage to aquatic ecosystems and marine life caused by oil spills and oily wastewater discharge, efficient, environment-friendly and sustainable oil/water separation technology has become an inevitable trend for current development. Herein, fabrics are recognized as eco-friendly materials for water treatment due to their good degradability and low cost. Particularly, fabrics with rough structures and natural hydrophilicity/oleophilicity enable the construction of superwetting surfaces for the selective separation of oil/water mixtures and even complex emulsions. Therefore, superwetting fabrics for efficiently solving oil spills and purifying oily wastewater have received extensive attention. Especially, Janus and smart fabrics are highly anticipated to enable the on-demand and sustainable treatment of oil spills and oily wastewater due to their changeable wettability. Moreover, the fabrication of superwetting fabrics with multifunctional performances for oily wastewater purification can further promote their practical industrial applications, such as photocatalytic, self-cleaning, and self-healing characteristics. However, some potential challenges still exist, which urgently need to be systematically summarized to guide the future development of this research field. In this review, firstly, the fundamental theories of wettability and the separation mechanisms based on special wettability are discussed. Then, superwetting fabrics for efficient oil/water separation are systematically reviewed, such as superhydrophobic/superoleophilic (SHB/SOL), superhydrophilic/superoleophobic (SHL/SOB), SHL/underwater superoleophobic (SHL/UWSOB), and UWSOB/underoil superoleophobic (UWSOB/UOSHB) fabrics. Most importantly, we highlight Janus, smart, and multifunctional fabrics based on their superwetting property. Correspondingly, the advantages and disadvantages of each superwetting fabric are comprehensively analyzed. Besides, super-antiwetting fabrics with superhydrophobic/superoleophobic (SHB/SOB) property are also introduced. Finally, the challenges and future research directions are explained.

Superhydrophobic Polyurethane Membrane with a Biomimetically Hierarchical Structure for Self-Cleaning

In this study, a stable and durable hexadecyltrimethoxysilane (HDTMS)/thermoplastic polyurethane (TPU) superhydrophobic film is successfully prepared by a simple and low-cost two-step method, namely, carrying out biomimetically hierarchical structures and low surface energy material modification concurrently. Meanwhile, effective parameters affecting the water contact angle (WCA) are studied and optimized. More importantly, under optimum parameters, the maximum WCA is 165°, the minimum slide angle (SA) is 3°, and the adhesion force is 13 μN, showing good self-cleaning performance. Besides, considerable mechanical stability to withstand 4000 tension or 5000 compression cycles, breathability, and moisture penetrability, as well as chemical resistance with sustained superhydrophobic properties in various harsh environments, are presented.

Fabrication of Durable, Chemically Stable, Self-Healing Superhydrophobic Fabrics Utilizing Gellable Fluorinated Block Copolymer for Multifunctional Applications

Limited durability and complex materials restrict the application of superhydrophobic fabrics in daily life. In this work, gellable fluorinated block copolymer poly(dodecafluoroheptyl methacrylate)-block-poly(3-(triethoxysilyl)propyl methacrylate) (PDFMA-b-PTEPM) was used to fabricate adhesive-free superhydrophobic poly(ethylene terephthalate) (PET) fabrics via a simple dip-coating technology and sol-gel reaction. The growth of silica nanoparticles builds up a rough hierarchical structure and provides sol-gel reaction sites of PTEPM segments. The grafting of block copolymer significantly reduced the surface free energy of the fabrics, resulting in an excellent superhydrophobicity with a water contact angle of 160.2°. Benefiting from extensive chemical bond grafting and cross-linking of the PTEPM segment, the fabric exhibits excellent durability in mechanical abrasion, chemical treatment, and washing. The coating has withstood 50 sandpaper abrasion cycles and 400 soft friction cycles and can maintain superhydrophobic properties in various solvents, freezing and a wide pH range. These superhydrophobic fabrics with a long life span possess self-cleaning, anti-icing, oil-water separation, and self-healing capabilities. The multifunctional fabrics developed in this study are durable and easy to produce, possessing the potential for applications in industry and daily life.

Rosin acid and SiO2 modified cotton fabric to prepare fluorine-free durable superhydrophobic coating for oil-water separation

Currently, fluorides and long-chain aliphatic compounds are the most frequent low surface energy chemicals utilized in the preparation of superhydrophobic coatings, but associated environmental risks and instability restrict their potential application in oil-water separation. This research described a superhydrophobic coating based on rosin acid and SiO₂ modified cotton fabric to overcome this challenge. By means of spray impregnation and UV-assisted click reaction, sulfhydryl modified rosin acid (RA), Octavinyl-POSS, and SiO₂ were grafted onto the surface of cotton fabric to obtain RA-SiO₂ superhydrophobic coating with rough surfaces such as lotus leaf and low surface energy. The RA-SiO₂ superhydrophobic coating had favorable self-cleaning ability, and also adsorbed various light and heavy oils to achieve efficient separation of oil-water mixtures. The separation efficiency was 96.3% and the permeate flux was 6110.84 (L⋅m^-2⋅h^-1) after 10 repetitions. The RA-SiO₂ superhydrophobic coating was found to be effective in separating oil-in-water and oil-in-water emulsions, and the separation mechanism was elaborated. In addition, it could effectively separate emulsions even after mechanical abrasion and chemical immersion, and had excellent stability. The fluorine-free and environmentally friendly low-cost superhydrophobic coating based on rosin acid is expected to play a significant potential in oil-water separation applications due to its excellent separation performance.

Fiber-based photothermal, UV-resistant, and self-cleaning coatings fabricated by silicon grafted copolymers of chitosan derivatives and gallic acid

Superhydrophobic and hydrophobic properties are generally created by adopting low surface free energy materials. Therefore, most studies have focused on creating surface hydrophobicity by using hydrophobic or fluorinated materials. However, few studies are reported on realizing surface hydrophobicity by directly introducing hydrophilic molecules, which is also a challenge. Herein, with platinum nanozyme as the catalyst, the novel hydrophobic coatings have been rapidly gained via anchoring the polymer of hydrophilic gallic acid and chitosan or chitosan quaternary ammonium salt onto cotton fabric surface. Notably, the novel hydrophobic coatings exhibit significant advances compared with conventional hydrophobic ones created by utilizing fluorinated or hydrophobic materials, which breaks the limitation of employing low surface energy materials for gaining surface hydrophobicity. Subsequently, the sodium methyl silicate was grafted on the polymer's coatings to strengthen surface hydrophobicity and the abrasion resistance of hydrophobicity. Interestingly, the heating could induce the hydrophilicity of cotton fabric to recover to hydrophobicity. Moreover, the hydrophobic coatings also possess good photothermal conversion, UV resistance, and anti-oxidation activity for self-cleaning application and oil water separation. Briefly, the present work may open a new direction for preparing novel hydrophobic coatings by combining gallic acid and chitosan-based macromolecular carbohydrates.

Scalable Fabrication of Highly Breathable Cotton Textiles with Stable Fluorescent, Antibacterial, Hydrophobic, and UV-Blocking Performance

Multifunctional cotton textiles that are highly breathable are desirable in a broad range of applications. However, it is still a big challenge to scale up production of such multifunctional cotton textiles. Herein, we developed a simple, scalable, and benign strategy to fabricate highly breathable multifunctional cotton textiles via mild surface modification. The 1,4-dihydropyridine (DHP) ring and gentamycin sulfate (GS) molecules were firmly attached to the cellulose chains under room temperature via a one-pot method. The resulting modified cotton textile showed integrated performances with bright fluorescence, good antibacterial behavior, hydrophobic behavior (contact angle of 134°), and UV-blocking (UPF being up to 69.2), which are very stable toward washing and various solvents. There is no obvious change in the whiteness, thermal stability, and mechanical performance of cotton fabrics after the surface modification. What's more, the air permeability of the modified cotton fabric was up to 31.3 (cm3/cm2)/s. This study not only focuses on the materials design and large-scale fabrication but also provides stable and multifunctional cotton textiles with broad application prospects for many fields.

Superhydrophobic polyurethane sponge based on sepiolite for efficient oil/water separation

Massive oil leakage accidents and illegal discharge of oily wastewater have not just destroyed the sustainability of the ecological environment but caused permanent damage to marine ecosystems, which makes it urgent to handle it. In this paper, by means of sol-gel, micro-nan silica that grew from the surface of fibrous sepiolite was organically modified with 1 H, 1 H, 2 H, 2 H-perfluorodecyltriethoxysilane (PFDS). The superhydrophobic sepiolite/silica firmly attached to the surface of polyurethane sponge under the action of oily epoxy resin with strong adhesion. The sponge exhibited superhydrophobicity and excellent selective oil adsorption capacity (19.98-40 times of their own weight). More importantly, besides the effective separation of immiscible oil-water mixtures (the separation rate reached 98.72%), it could also efficiently separate oil with water and oil with salt solution emulsions. In addition, the sponges kept hydrophobic even after floating in extremely corrosive liquids for 20 h, showing a strong resistance to strong acidic as well as alkaline liquids. After 100 times of mechanical compression, the three-dimensional structure of sponge held still and the water contact angle was greater than 144°, demonstrating an excellent mechanical stability, which provided a reference for its practical application in oil-water separation.

Robust multifunctional fluorine-free superhydrophobic fabrics for high-efficiency oil-water separation with ultrahigh flux

The limited robustness and complex preparation process greatly hinder the large-scale use of superhydrophobic surfaces in real life. In this work, we adopt a simple method to prepare robust fluorine-free superhydrophobic cotton fabrics by a facile dip-coating method based on silica microparticles and titanium dioxide nanoparticles. Microparticles and nanoparticles are used to build a suitable rough hierarchical structure, while strong bonds are formed between fabric and particles by a silane coupling agent. The cross-linking reaction between the isocyanate group of trimers of hexamethylene diisocyanate (HDI) and the hydroxyl group of each component in the condensation reaction further increases the bonding between the coating and the cotton fabric. In addition, polydimethylsiloxane (PDMS) is used as a low-surface-energy material to modify the fabric surface. The resulting coating shows excellent superhydrophobic properties with a water contact angle of 161.7°. Meanwhile, the prepared superhydrophobic fabric exhibits excellent durability and stability after sandpaper wearing, washing, and UV radiation, as well as treatment with various organic solutions, boiling water and different pH solutions. Moreover, the superhydrophobic fabric displays excellent UV protection performance and high oil-water separation efficiency (>99% after 30 cycles) with ultrahigh flux up to 20 850 L m^-2 h^-1.

Large-Scale Fabrication of Graded Convex Structure for Superhydrophobic Coating Inspired by Nature

The addition of toxic substances and poor durability severely limit the market applications of superhydrophobic coatings in the oil−water-separation industry, anti-icing, and self-cleaning surfaces. In order to solve the above problems, a stable, strong, fluorine-free superhydrophobic coating was prepared according to natural inspiration. In this study, polydivinylbenzene (PDVB) was produced by the hydrothermal method, and micro-nanoparticle clusters composed of PDVB particles of different sizes were prepared by controlling the ratio of raw materials, which was then attached to the substrate surface by a simple spraying technique. A rough coating with a lotus-leaf-like layered protruding structure was constructed by depositing particle clusters of different sizes. In the end, the prepared coating showed attractive superhydrophobicity, with a maximum contact angle (CA) that reached up to 160°. In addition, the coating had long-lasting superhydrophobic properties in various environments, such as common liquid and acidic and alkaline solutions. Moreover, in the oil−water-separation process, the superhydrophobic filter paper was still able to obtain a separation efficiency of more than 85% after being used 50 times, and it maintained a contact angle of >150°. At the same time, the coating had excellent dye resistance and self-cleaning performance.

Bioinspired antifouling Fe-based amorphous coating via killing-resisting dual surface modifications

Fe-based amorphous coatings with outstanding corrosion resistance are promise for marine applications. However, these coatings encounter a great challenge of biofouling in marine environments. Inspired by the unique micro-nano hierarchical structure of shark skin with excellent antifouling properties, in this paper, we construct a bioinspired Fe-based amorphous coating with killing-resisting dual-effect via proper surface modifications, i.e., the modification with micro-patterned nanostructured Cu₂O fibers (killing effect), followed by the modification with superhydrophobic surface (resisting effect). As a result, the modified amorphous coating exhibits impressive antifouling properties, achieving 98.6% resistance to Nitzschia closterium f. minutissima, 87% resistance to Bovine serum albumin protein and 99.8% resistance to Pseudomonas aeruginosa, respectively. The remarkable antifouling performance is attributed to a synergistic antifouling mechanism from both resisting effect and killing effect, wherein the superhydrophobic surface provides a barrier to resist protein adsorption, while the patterned nanostructured Cu₂O fibers supply Cu⁺ ions to kill bacterial cells. In addition, the modified amorphous coating also exhibits excellent mechanical robustness, which ensures the durability of the Fe-based amorphous coating in practical services. This work may promote the development of new durable metal-based coatings integrated with anti-fouling and anti-corrosion properties.

Preparation strategy and evaluation method of durable superhydrophobic rubber composites

Superhydrophobic rubber composites have broad application prospects in national defense, industrial and agricultural production and daily life due to their special surface wettability. However, its poor durability at present seriously limits its practical application. Microstructure and low surface energy substances are the decisive factors to realize superhydrophobic surface. Therefore, three strategies to improve the durability of superhydrophobic surface were put forward, including improving the mechanical strength of microstructure, enhancing the adhesion between coating and substrate, and constructing self-repairing surface. On this basis, the preparation techniques of durable superhydrophobic rubber composites were summarized, and then the evaluation methods of durability of superhydrophobic rubber composites were introduced in detail from mechanical durability and chemical durability.

Robust and durable liquid-repellent surfaces

This review provides a comprehensive summary of characterization, design, fabrication, and application of robust and durable liquid-repellent surfaces.

Applications of Nanotechnology in Smart Textile Industry: A Critical Review

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Current trends of using nanotechnology in textile industries.

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Nanotechnology-driven techniques for fabrication and modification of textile fibers.

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Wearable nanotechnology for energy storage, sensing, drug release, optics, electronics and photonics.

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Environmental concerns associated with nanotechnology processed textiles.

Background

In recent years, nanotechnology has been playing an important role in designing smart fabrics. Nanomaterials have been employed to introduce in a sustainable manner, antimicrobial, ultraviolet resistant, electrically conductive, optical, hydrophobic and flame-retardant properties into textiles and garments. Nanomaterial based smart devices are now also being integrated with the textiles so as to perform various functions such as energy harvesting and storage, sensing, drug release and optics. These advancements have found wide applications in the fashion industry and are being developed for wider use in defence, healthcare and on-body energy harnessing applications.

Aim of review

The objective of this work is to provide an insight into the current trends of using nanotechnology in the modern textile industries and to inspire and anticipate further research in this field. This review provides an overview of the most current advances concerning on-body electronics research and the wonders which could be realized by nanomaterials in modern textiles in terms of total energy reliance on our clothes.

Key scientific concepts of review

The work underlines the various methods and techniques for the functionalization of nanomaterials and their integration into textiles with an emphasis on cost-effectiveness, comfort, wearability, energy conversion efficiency and eco-sustainability. The most recent trends of developing various nanogenerators, supercapacitors and photoelectronic devices on the fabric are highlighted, with special emphasis on the efficiency and wearability of the textile. The potential nanotoxicity associated with the processed textiles due to the tendency of these nanomaterials to leach into the environment along with possible remediation measures are also discussed. Finally, the future outlook regarding progress in the integration of smart nano-devices on textile fabrics is provided.

A multifunctional and environmentally safe superhydrophobic membrane with superior oil/water separation, photocatalytic degradation and anti-biofouling performance

Wastewater is typically complicated with spilled oil, water soluble toxic dyes and microorganisms, making it hard to be processed and causing a significant threat to the environmental safety and human health. In this paper, we demonstrate a simple solution immersion method to obtain a multifunctional cellulose-based membrane (CBM) that possesses both superhydrophobicity with a water contact angle of 163° and superior functionalities including self-cleaning, oil-water separation, anti-biofouling, and photocatalytic degradation capabilities. The achievement of separation efficiency (96%), comparatively high flux (141 L·m^-2·h^-1) and recyclable (7 times) oil/water separation performance is attributed to the robust superhydrophobicity enabled by the synergy of metal oxide (i.e., CuO) nanostructure coating and stearic acid (SA) modification. The superhydrophobic CBM also preferentially adsorbs organic dyes in aqueous solution, e.g., methylene blue (MB), promoting their efficient decomposition (about 70.3% of MB decomposed in 3 h) with high recyclability under UV irradiation. Most remarkably, the CBM exhibits superior anti-biofouling capability and persistently resists the algae adhesion in long duration (over 20 days), as a result of the self-cleaning ability as well as the antimicrobial property of CuO nanoparticles. Our finding here paves the way to use simple, cost-effective, environmentally safe, and reliable method to fabricate multifunctional materials for wastewater treatment in complex environments.

Asymmetric Superhydrophobic Textiles for Electromagnetic Interference Shielding, Photothermal Conversion, and Solar Water Evaporation

Flexible and multifunctional textiles have potential applications in self-cleaning and portable electronic product applications, but the current problem that needs to be solved is to maintain their inherent breathability and flexibility while expanding other functional applications. Herein, we adopt the layer-by-layer assembly method to develop a multifunctional textile with superior asymmetric superhydrophobicity, excellent electromagnetic interference (EMI) shielding, outstanding photothermal conversion, and solar water evaporation. The synergistic effect of SiO₂ nanoparticles/poly(dimethylsiloxane) (PDMS) and 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES) endows the textile with a water contact angle of 160°. MXene provides high conductivity (1200 S/m) and EMI shielding effects (36 dB) for multifunctional textiles. In addition, the multifunctional textile exhibits excellent photothermal conversion, and satisfactory solar water evaporation efficiency (80%) and rate (1.22 kg/(m² h)) under 1 sun. Therefore, the prepared multifunctional textile has great potential in multiscene applications.