Superhydrophobic cotton fabrics prepared by sol–gel coating of TiO2 and surface hydrophobization

Abstract

By coating fibers with titania sol to generate a dual-size surface roughness, followed by hydrophobization with stearic acid, 1H,1H,2H,2H-perfluorodecyltrichlorosilane or their combination, hydrophilic cotton fabrics were made superhydrophobic. The surface wettability and topology of cotton fabrics were studied by contact angle measurement and scanning electron microscopy. The UV-shielding property of the treated fabrics was also characterized by UV-vis spectrophotometry.     

A novel method to prepare a microflower-like superhydrophobic epoxy resin surface

A novel microflower-like superhydrophobic epoxy resin surface was obtained using a novel method. The water contact angle and sliding angle of the superhydrophobic epoxy resin surface was 158 ± 1.7° and 3°, respectively. The as-prepared microflower-like superhydrophobic epoxy resin surface also showed superhydrophobic property in the pH range of 3–14. After being stored in ambient environment for one month, no decrease in water contact angle was observed.     

Fabrication of ZnO submicrorod films with water repellency by surface etching and hydrophobic modification

Superhydrophobic ZnO submicrorod films have been fabricated on zinc sheets through an H₂O₂-assisted surface etching process and subsequent surface modification with a monolayer of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FDS). The crystal structure, chemical compositions, morphologies, and wettability of the resultant ZnO films were analyzed by means of X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and water contact angle measurements. It is found that the surface of the as-prepared ZnO films on zinc substrate was hydrophobic with a water contact angle of 95 ± 2°, whereas after modification with FDS, the film exhibited superhydrophobicity and the water CA increased to 154 ± 2°. It is shown that both the higher surface roughness and the lower surface free energy play an important role in creating the superhydrophobic films.     

Preparation and characterization of self-cleaning stable superhydrophobic linear low-density polyethylene

Abstract

Porous superhydrophobic linear low-density polyethylene (LLDPE) surface was prepared by a simple method. Its water contact angle and sliding angle were 153±2° and 10°, respectively. After contamination, 99% of the contaminant particles were removed from the superhydrophobic LLDPE surface using artificial rain. The superhydrophobic LLDPE surface showed high stability in the pH range from 2 to 13. When LLDPE samples were stored in ambient environment for one month, their water contact angle and sliding angle remained constant. Their superhydrophobic property was also maintained after annealing in the temperature range 10–90 °C.     

Fabrication and characterization of superhydrophobic high opacity paper with titanium dioxide nanoparticles

A new type of paper with superhydrophobic surface was prepared by addition of modified nano-TiO₂ to cellulose pulp. Nano-TiO₂ powder was first dispersed with a high-speed homogenizer, followed by surface modification with the coupling agent, 3-(trimethoxysilyl) propyl methacrylate (MPS). The superhydrophobic and opaque paper was obtained by adding the modified nano-TiO₂ to plant fiber to change its characteristics from hydrophilic to hydrophobic. The effects of the initial content of the coupling agent MPS used, on the weight percentage of MPS attached on the surface of nano-TiO₂ were studied. The obtained paper was characterized by contact angle measurements and SEM. The results showed that the water contact angles for the modified paper ranged from 126.5 to 154.2°, and the sliding angle was <3°. Moreover, many well-dispersed nano-TiO₂ protuberances were observed on the surface of the paper, which further confirmed that the obtained paper was superhydrophobic on account of its nanostructure. Comparative optical studies performed on the paper handsheets revealed a much higher opacity for the sample with the MPS-modified-TiO₂ nanoparticles.     

Different wetting behavior of alkyl- and fluorocarbon-terminated films based on cupric hydroxide nanorod quasi-arrays

Nanorods of cupric hydroxide (Cu(OH)₂) crystals with a diameter of about 100–500 nm and length of about tens of micrometers were directly fabricated on copper foils by alkali assistant surface oxidation technique. It was found that chemical modification with stearic acid (STA) or 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PDES) led to significant increase in the contact angles of the Cu(OH)₂ nanorod quasi-array film, which could be related to the chemical modification and the roughened structure of the film surfaces. Compared with STA-modified surface, PDES-modified surface had a lower contact angle hysteresis (CAH) and adhesion for water droplets, possibly due to lower surface free energy of PDES than STA.     

Preparation of superhydrophobic surfaces on cotton textiles

Superhydrophobic surfaces were fabricated by the complex coating of silica nanoparticles with functional groups onto cotton textiles to generate a dual-size surface roughness, followed by hydrophobization with stearic acid, 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane or their combination. The wettability and morphology of the as-fabricated surfaces were investigated by contact angle measurement and scanning electron microscopy. Characterizations by transmission electron microscopy, Fourier transformation infrared spectroscopy, and thermal gravimetric analysis were also conducted.     

Antibioadhesive Superhydrophobic Syringe Needles Inspired by Mussels and Lotus Leafs

Fouling of surfaces due to bioadhesion is one of the hurdles in terms of their practical applications. Inspired by mussel and lotus leaf, antibioadhesive superhydrophobic syringe needles are fabricated by sequential bonding of polydopamine, Ag nanoparticles, and 1H,1H,2H,2H‐perfluorodecanethiol (PFDT). The morphology and surface chemical composition of the needles are characterized. The wetting properties and antibioadhesive properties of the needles are evaluated by contact angle (CA) and sliding angle (SA) of water and various aqueous solutions, and their residues on the needles after repeatedly used for liquid handling. The superhydrophobic needles show a rough surface with a layer of PFDT, which endow them with very high CA and low SA for water and various aqueous solutions. In addition, the aqueous solutions are in the Cassie–Baxter state on the surface of the superhydrophobic needles. Thus, the adhesion force between the superhydrophobic needles and aqueous solutions is very low. This endues the needles with excellent antibioadhesive properties and can be repeatedly used for withdrawing and dispensing various aqueous solutions. Moreover, the superhydrophobic needles can be used for the transport of aqueous solutions at high accuracy. The antibioadhesive superhydrophobic needles may find applications in various fields such as liquids transport and inkjet printing devices.     

Vi-PDMS/S-SiO2超疏水聚酯纤维织物的制备及性能研究

目的 基于普通织物材料防水性较差的问题,制备一种具有超疏水涂层的聚酯纤维织物,并对其性能进行研究。方法 以聚酯纤维织物为基材,基于紫外光固化技术通过浸涂法,使用商用气相纳米SiO₂颗粒(S-SiO₂)、端乙烯基聚二甲基硅氧烷(Vi-PDMS)在织物表面构筑微纳粗糙结构,获得超疏水的织物。采用扫描电子显微镜、水接触角测量仪对其微观结构和疏水性能进行表征,并通过机械摩擦实验对其超疏水稳定性进行考察。结果 当Vi-PDMS和S-SiO₂质量比为1∶4时,选择交联剂为三羟甲基丙烷三丙烯酸酯(TMPTA)制备的聚酯纤维织物表面的水接触角可达到151°,滚动角可达9°;且经过40次循环摩擦后,其表面水接触角仍大于140°,具有一定的耐磨性。结论 基于紫外光固化技术,采用操作简便的浸涂法制备的聚酯纤维织物具有优异的超疏水性能和一定的耐磨性,为织物超疏水性能研究提供参考,有望应用于超疏水聚酯纤维织物领域。     

Laser‐Induced Graphene in Controlled Atmospheres: From Superhydrophilic to Superhydrophobic Surfaces

The modification of graphene‐based materials is an important topic in the field of materials research. This study aims to expand the range of properties for laser‐induced graphene (LIG), specifically to tune the hydrophobicity and hydrophilicity of the LIG surfaces. While LIG is normally prepared in the air, here, using selected gas atmospheres, a large change in the water contact angle on the as‐prepared LIG surfaces has been observed, from 0° (superhydrophilic) when using O₂ or air, to >150° (superhydrophobic) when using Ar or H₂. Characterization of the newly derived surfaces shows that the different wetting properties are due to the surface morphology and chemical composition of the LIG. Applications of the superhydrophobic LIG are shown in oil/water separation as well as anti‐icing surfaces, while the versatility of the controlled atmosphere chamber fabrication method is demonstrated through the improved microsupercapacitor performance generated from LIG films prepared in an O₂ atmosphere.     

透明超疏水玻璃表面的制备及性能研究

目的研究透明超疏水玻璃的制备及性能。方法以纳米二氧化硅和无水乙醇为原料制成半透明乳液,然后将乳液喷涂在玻璃表面,再通过接触角测试、透光率测试仪等手段对玻璃表面的性能进行研究。结果在玻璃基材表面构建了与水滴接触角高达158°±2°,滚动角低至1°的透明超疏水表面。当喷涂液中纳米二氧化硅的质量分数为1.5%时,获得的超疏水玻璃表面具有优异的防水性、抗污易清洁性和透明性。结论在玻璃基底上制备透明超疏水表面可以大大提高玻璃表面的防水、防污性,并使玻璃表面更易于清洁,有利于减少玻璃包装材料清洗时的用水量和洗涤剂用量,从而增强玻璃包装材料的生态环保效应。     

Superhydrophobic sodium silicate based silica aerogel prepared by ambient pressure drying

The superhydrophobic silica aerogel was prepared by using less expensive sodium silicate as a main silica source through a cost-effective and simple route via ambient pressure drying. The sodium impurity was first eliminated by mixing sodium silicate with a co-precursor methyltriethoxysilane (MTES) followed by ion exchange process. The hydrogel was formed by gelation and the alcogel was further obtained by alcoholization of the hydrogel. The surface of alcogel was modified by reacting with trimethylchlorosilane (TMCS) diluted in n-hexane. It was suggested that MTES accelerated water expelling from the hydrogel, while TMCS modified the surface of silica network by replacing Si–OH with Si–C. As a result, the obtained silica aerogel exhibited excellent physical properties with less than 10% volume shrinkage. The density, surface area and cumulative pore volume were 0.12 g cm⁻³, 684.44 m² g⁻¹, and 3.55 cm³ g⁻¹, respectively. The optical transmission reached 82.8% with the water contact angle of 146°.     

ZnO/E-51复合涂料上超疏水表面的制备

采用ZnO和环氧树脂机械搅拌制备ZnO/E-51复合涂料,通过真空袋压、室温固化成型,再通过化学刻蚀与表面修饰,在ZnO/E-51复合涂料上制备出超疏水表面。采用扫描电镜和动/静态接触角分析仪,表征表面的形貌和疏水性。结果表明化学刻蚀在复合涂料表面构建了具有微-纳米尺度二元粗糙结构;采用1%(质量分数)的硬脂酸修饰,可改变复合涂料表面微-纳米尺度二元粗糙结构,影响表面的疏水性能,当修饰时间为30min时,其表面与水的平均接触角最高达152.21°。     

碳纤维颗粒增强CeO2/PMMA/PVDF超疏水复合涂层及其耐磨性能

提高耐磨性能是推动仿生超疏水表面走向实际应用的关键挑战之一。设计了二氧化铈微米粒子增强PMMA/PVDF超疏水复合涂层配方,获得了水珠接触角达152°、水珠滚动角为5°的超疏水复合涂层。该涂层经过落砂磨损试验后接触角下降为103°、滚动角增大为20°。采用碳纤维颗粒对CeO2/PMMA/PVDF超疏水复合涂层进行增强,优化配方的接触角达153°、滚动角达到5°。经过相同落砂磨损试验后,增强后的复合涂层水珠接触角能在一定程度磨损后达到140°左右。可见,CeO2/PMMA/PVDF复合涂层具有良好的超疏水性能,碳纤维颗粒增强是提高该涂层耐磨性能的有效方法。     

A one-step process to engineer superhydrophobic copper surfaces

Superhydrophobic surfaces are conventionally prepared employing two steps: roughening a surface and lowering their surface energy. In the present work, a direct voltage (DC) is applied between two copper plates immersed in a dilute ethanolic stearic acid solution. The surface of the anodic copper electrode transforms to superhydrophobic due to a reaction between copper and stearic acid solution. The fabrication process of superhydrophobic copper surfaces is simplified in just one-step. The surface of the anodic copper is found to be covered with flower-like low surface energy copper stearate films providing the water contact angle of 153 ± 2° with the roll-off properties.     

MB8镁合金超疏水表面的制备和润湿性

通过激光加工在MB8镁合金表面构造具有规则结构的纹理,再制备1H,1H,2H,2H-全氟葵烷基三氯硅烷(FDTS)自组装分子膜,从而构建了MB8镁合金超疏水表面。用扫描电子显微镜和接触角测量仪观察和测量试样表面的形貌和润湿性。结果表明,激光加工在试样表面构造的粗糙结构和低表面能物质FDTS自组装分子膜使该试样具有超疏水性;经激光加工和沉积自组装分子膜后,MB8镁合金试样表面对水的接触角显著增大(达到150°以上)。将MB8镁合金超疏水表面加工成漂浮平台,承载能力的测试结果表明,超疏水平台的漂浮承载能力明显比非超疏水性平台的大,平台的承载能力与接触角的数值成正比。理论计算结果和"气垫"的存在表明,该超疏水表面符合Cassie-Baxter。状态模型,对接触角理论值与测量值的分析表明分级粗糙结构对超疏水表面构建有重要作用。     

Screening the UV‐blocking and antimicrobial properties of herbal nanoparticles prepared from Aloe vera leaves for textile applications

Nanomaterials play a vital role in textile industries due to their unique properties and applications. There is an increase in the use of nanoscale phyto products in textiles to control the bacterial infection in fabrics. Here, natural herbal nanoparticles of different sizes were prepared from shade‐dried Aloe vera plant leaves using ball milling technique without any additives. The amorphous herbal A. vera nanoparticles possess an average particle size of 40 ± 2 nm and UV‐absorption maximum at 269 nm. A. vera nanopowders–chitosan nanocomposites were prepared and coated on cotton fabrics using pad‐dry cure method. The evaluation of antibacterial activity against Escherichia coli (22.05 ± 0.06 mm) and Staphylococcus aureus (27.17 ± 0.02 mm), UV‐protection properties (UV‐protection factor = 57.2 ± 0.1), and superhydrophobic nature (155 ± 3°) of the prepared herbal nanoparticles and their composites were analysed by disc diffusion, UV–visible spectral analysis, and contact angle analysis. Understanding the functional properties of herbal nanoparticles, coated particles on fabrics highlights their potential applications in protective clothing with better antimicrobial properties, hydrophobicity, and UV‐protection properties. This study of using A. vera herbal nanoparticles in textiles significantly enhances the fabric performance to develop protective textile fabrics in defence and biomedical fields.Inspec keywords: nanoparticles, particle size, nanofabrication, nanomedicine, antibacterial activity, biomedical materials, hydrophobicity, ultraviolet spectra, visible spectra, radiation protection, textile fibres, cotton fabrics, ball milling, X‐ray diffraction, light scattering, scanning electron microscopy, X‐ray fluorescence analysis, fluorescence, amorphous state, nanocomposites, filled polymers, protective coatings, curing, microorganisms, biodiffusion, contact angle, surface morphology, protective clothingOther keywords: UV‐blocking, antimicrobial properties, disc diffusion, UV‐visible spectral analysis, contact angle analysis, morphological characteristics, protective clothing, protective textile fabrics, biomedical fields, superhydrophobic nature, UV‐protection factor, UV‐protection properties, Staphylococcus aureus, Escherichia coli, pad‐dry cure method, cotton fabrics, A. vera nanopowders‐chitosan nanocomposites, UV‐absorption maximum, average particle size, amorphous herbal A. vera nanoparticles, X‐ray fluorescence spectrometry, scanning electron microscopy, dynamic light scattering, UV‐visible spectrophotometry, X‐ray diffraction, ball milling, shade‐dried Aloe vera plant leaves, natural herbal nanoparticle size, bacterial infection, nanoscale phyto products, textile industries, nanomaterials, textile applications     

Preparation of superhydrophobic boehmite and anatase nanocomposite coating films

Developing a surface with water-repelling and self-cleaning ability has attracted much interest in nano-technology. We prepared superhydrophobic films in this study using a mixture of small anatase particles and large boehmite particles. Additionally, a N₂ automated adsorption apparatus, atomic force microscopy and contact angle meter were employed to examine the effects of the added boehmite and anatase to the boehmite ratio on the roughness, micropore ratio and contact angle of the hydrophobic films.As boehmite addition increased from 0 to 8 wt.%, the average roughness increased up to 30 nm, which resulted in the water contact angles increasing from 105° to 155°. The hardness of the films increased from 6B to 2H. The addition of a proper amount of small anatase particles into the large boehmite particles could lead to increasing the micropore ratio in the films, which would enhance the contact angle.     

玻璃纤维增强环氧复合材料上超疏水表面层的制备

先采用真空袋压法制备含CaCO3/环氧树脂表面功能层的玻璃纤维增强环氧树脂复合材料,再通过化学刻蚀与表面修饰,在玻璃纤维增强环氧树脂复合材料上制备出超疏水表面。采用扫描电镜和动/静态接触角分析仪,表征表面的形貌和疏水性,结果表明,在复合材料表面构建了具有微-纳米尺度二元粗糙结构;采用1%(质量分数)的硬脂酸修饰后,其表面与水的接触角最高达160.03°;制备的超疏水表面结构在室温环境下具有长期的稳定性。     

Facile preparation of superhydrophobic surface with high adhesive forces based carbon/silica composite films

Glass substrates modified by carbon/silica composites are fabricated through a two-step process for the preparation of a superhydrophobic surface (water contact angle ≥ 150°). Carbon nanoparticles were first prepared through a deposition process on glass using a hydrothermal synthesis route, then the glass was modified by SiO₂ using the hydrolysis reaction of tetraethylorthosilicate at room temperature. It is not only a facile method to create a superhydrophobic surface, but also helps to form a multi-functional surface with high adhesive forces.