One-pot fabrication of robust hydrophobia and superoleophilic cotton fabrics for effective oil-water separation

A one-pot sonochemical irradiation method was developed for the fabrication of superhydrophobic and superoleophilic cotton fabric from a solution consisting of branched silica nanoparticles and tetraethoxysilane-dodecyltrimethoxysilane sol. The silica/sol-coated cotton fabric could be wetted by liquids of low surface tension, but was water repellent with a water contact angle of 159 ± 1.2° and water shedding angle of 6 ± 0.8°. The as-prepared cotton fabric could be used as effective materials for the separation of oil from water with separation efficiency as high as 98.2% and maintained separation efficiency above 94% after 30 separation cycles for the kerosene-water mixture. Moreover, the superhydrophobic and superoleophilic cotton fabric could maintain stable superhydrophobicity after treatment with strong acidic and alkali solutions, and harsh mechanical damage. Therefore, this reported robust superhydrophobic cotton fabric exhibits encouraging practical application for oil-water separation.     

Fabrication of a Bio-Based Superhydrophobic and Flame-Retardant Cotton Fabric for Oil–Water Separation

It is an urgent task to develop environmentally friendly and flame retardant durable oil–water separation materials. A green TA/B@PDA coating derived from bio-based materials such as tannic acid (TA), borax (B), and polydopamine (PDA) is deposited on cotton fabric through facile dip-coating method and step-by-step assembly method. A series of methods are used to characterize the as-prepared cotton fabric. PDA provides a reactive interface, while n-dodecyl mercaptan enhances the hydrophobicity of the surface with a water contact angle (WCA) and shedding angle (SA) of 153.3° ± 1.2° and 9° ± 0.8°, respectively. The as-prepared fabric exhibits outstanding oil/water separation efficiency (>98.5%) for various types of oil, and wear resistivity, washability, and reusability. Meanwhile, combustion test and limit oxygen index (LOI) test show that the modified fabric has excellent flame retardant performance. The cone calorimeter test (CCT) indicates that compared with the pristine cotton fabric, the peak heat release rate (PHRR) and total heat release (THR) of the TA/B@PDA cotton is decreased by 50% and 32%, respectively. Through the analysis of char residues, the flame retardant mechanism is studied. This method provides a general green way for the construction of superhydrophobic surfaces, and can be further applied to the broad fields of durable oil–water separation.     

Fabrication of durable superhydrophobic and superoleophilic cotton fabric with fluorinated silica sol via sol–gel process

Superhydrophobic and superoleophilic cotton fabric was successfully prepared with fluorinated silica sol via a facile sol–gel method. A fluorinated polymeric sol–gel precursor (PHFBMA-MTS) was synthesized via free-radical polymerization by using hexafluorobutyl methacrylate (HFBMA) in the presence of (3-mercaptopropyl)trimethoxysilane (MTS) as the chain transfer agent, which led to the formation of fluoropolymer with alkoxysilane end groups. Then the fluorinated silica sol was prepared by introducing PHFBMA-MTS as the co-precursor of tetraethylorthosilicate (TEOS) in the sol–gel process with ammonium hydroxide as the catalyst, which was then used to fabricate superhydrophobic and superoleophilic fabric coatings through a simple dip-coating method. The coated fabrics showed superhydrophobic property with a high water contact angle of 154.1° and superoleophilic property with an oil contact angle of 0°. Moreover, the coated fabrics still kept superhydrophobicity even after ultrasonic treatment, as well as for organic solutions, acidic solutions. Thus, the coated fabrics were successfully applied to separate oil–water mixture with separation efficiency up to 99.8%. More importantly, the separation efficiency had no significant change after 20 cycles of oil–water separation. These present a simple, low-cost, and durable approach to achieve industrialized application of coated fabrics in oil–water separation. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47005.     

A facile method to fabricate durable super‐hydrophobic cotton fabric

This article presents the fabrication of super‐hydrophobic cotton fabric using titanium dioxide nanoparticles and tetraethyl orthosilicate, alongside control samples modified by 1H,1H,2H,2H‐perfluorooctyltriethoxysilane. The samples were analyzed using scanning electron microscopy and Fourier transform infrared spectrometry, and then, the water contact angles were measured. Moreover, the durability of the hydrophobic surface was examined by measuring the abrasion resistance and laundering durability. For the tetraethyl orthosilicate‐treated fabric, the water contact angle reached 150.3°, whereas that for the 1H,1H,2H,2H‐perfluorooctyltriethoxysilane‐treated fabric was 154.1°. After 300 abrasion cycles (or 40 min of laundering), the water contact angles of cotton fabrics treated with a 20% tetraethyl orthosilicate treatment solution dropped by 6.67% (or 2.86%). Therefore, hydrophobic cotton fabrics can be obtained via treatment with tetraethyl orthosilicate solution, which is more environmentally friendly than that obtained via fluorosilanes such as 1H,1H,2H,2H‐perfluorooctyltriethoxysilane. J. VINYL ADDIT. TECHNOL., 26:3–9, 2020. © 2019 Society of Plastics Engineers     

Preparation and oil–water separation evaluations of polypropylene/low‐melt‐point polyester composites reinforced by thermal bonding and one‐step solution immersion

Nonwoven fabrics have been fabricated for oil–water separation, but simplifying the manufacturing processes is still a challenge. In this work, a facile and easily scaled up approach based on thermal bonding and one‐step solution immersion has been successfully developed to prepare nonwoven fabrics with high separation efficiency and flux of oil. Here, polypropylene (PP) and low‐melt‐point polyester (LPET) fibers with a unique sheath–core structure are employed to form PP/LPET nonwoven fabrics. Thermal bonding by hot press and hydrophobic treatment with 1H,1H,2H,2H‐perfluorodecyl‐1‐thiol (PFDT) are used to manufacture oil–water separation nonwoven fabrics. Effects of the ratio of LPET fibers and the concentration of PFDT are discussed in terms of mechanical properties, morphology, surface chemical composition, water contact angle and performance of oil–water separation and flux of the nonwoven fabrics. The results show that the strength of the nonwoven fabrics gradually increases with increasing ratio of LPET fibers. After immersion in PFDT, the nonwoven fabrics show high hydrophobicity with a water contact angle of 143°. They can be used to separate oil–water mixtures. The separation efficiency is 97–99% and the oil flux is 62 364.92 L m^?2 h^?1. This study provides a new prospect for simple introduction of a hydrophobic agent on a nonwoven fabric to achieve various functional oil–water separation materials. © 2020 Society of Chemical Industry     

Oil–water separation capability of superhydrophobic fabrics fabricated via combining polydopamine adhesion with lotus‐leaf‐like structure

By the combination of dual bionic on the superhydrophobicity of lotus leaf and the bioadhesion of mussel adhesive protein, the nanoparticles were strongly immobilized onto the surface of cotton fabric to form superhydrophobic and superoleophilic coating. The as‐prepared fabric can be used as effective material for separating various oil/water mixtures. The separation efficiency can reach 99.0%, 97.6%, 98.1%, 96.0%, 94.2%, and 94.5% for toluene/water, n‐hexane/water, chloroform/water, paraffin oil/water, linseed oil/water, and crude oil/water mixtures with volume ratio of 1 : 4, respectively. In addition, the obtained fabric still kept stable superhydrophobicity and high separation efficiency for oil/water mixtures after using repeatedly for 90 cycles or ultrasonic treatment. They also exhibited excellent chemical durability in harsh conditions of strong acidic and alkaline solutions. Owning to high separation efficiency, stable recyclability, low cost, scalable fabrication, and excellent durability, the as‐prepared fabric can be considered as promising material for the separation of oil/water mixtures. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42614.     

Preparation and study of stable fluorine-free superhydrophobicity of cotton fibers

This paper proposes a method of directly modifying the surface of cotton fiber to achieve super-hydrophobic properties. The process was directly utilized the long-chain alkyl siloxane and the nano-SiO₂ modified cotton cloth, which was simple to operate, low in cost and environmentally friendly. This study discussed the influence of solvent ratio, reactant content and ammonia content on hydrophobicity. The solvent ratio had the greatest influence, and the maximum water contact angle (CA) changes were70° ± 1°. The maximum water CA of the superhydrophobic cotton fabric prepared after process selection was 162 ± 1.5°; it had good acid, alkali and salt resistance. After 24 h in a solution with a pH of 1–14, CA remained almost unchanged; After 144 h in a 3.5% salt solution, CA stabilized above 132°; it had self-cleaning properties; it had good selective adsorption performance, which can quickly separate oil and water; it had good mechanical stability. After 300 times abrasion of sandpaper, which still shows hydrophobic properties.     

Fabrication of flower clusters-like superhydrophobic surface via a UV curable coating of ODA and V-PDMS

In this work, a flower clusters-like superhydrophobic surface was fabricated via an ultraviolet (UV) curable coating of octadecylamine (ODA) and vinyl-terminated polydimethylsiloxane (V-PDMS). ODA self-assembled into many flower clusters-like structures on the surface of the coating, increasing the roughness of the coating surface without additional nanoparticles. V-PDMS formed a highly crosslinked network under a UV lamp, which would be helpful for a robust superhydrophobic surface. The obtained PDMS/ODA fabric showed water contact angle of 161° and sliding angle of 5°. The durability of the superhydrophobic surface was tested by water impacting, tube brush scrubbing, knife scratching, hand twisting, finger pressing, tape adhesion, abrasion, continuous rinsing, and chemical conditions. The experimental results indicated that the superhydrophobic surface have good durability for long service life. Moreover, the PDMS/ODA fabric could selectively absorb oils from water with good separation performance. This work will provide a facile, low cost, and versatile method to prepare superhydrophobic surfaces, and enhance their efficiency of oil–water separation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48210.     

Performance evaluation of modified fabricated cotton membrane for oil/water separation and heavy metal ions removal

Preparation of effective membrane with special surface treatment for oil/water separation having promising future and low manufacturing cost. The suggested membrane was fabricated by a simple treatment via increasing the hydrophilicity of the cotton fabric surface. The cotton fabric was impregnated in poly(acrylic acid-co-N-methylol acrylamide), poly(AA-co-NMA), where NMA acts as bonding agent. Sodium hypophosphite (SHP) was added to the modification solution to enhance the bonding between the cotton fabric and the PAA. The modified fabric was thermally dried and cured at different temperatures. It was found that, the presence of 3.5% NMA and addition of 5% SHP to the modification solution then curing at 190°C gave the highest amount of bonded PAA to the cotton fabric. The success of the modification process was confirmed by scanning electron microscope, Fourier transformer infrared and the increase in the contact angle of the cotton fabric after modification. Furthermore, the prepared membrane was evaluated for oil (n-hexane, toluene, and petroleum ether)/water separation and also for heavy metal ions removal (Cd²⁺ and Co²⁺). Neutralization of the produced membrane with ammonium hydroxide resulting in a higher contact angle and consequently higher separation efficiency for oil/water mixtures and higher performance for heavy metal ions removal compared to the unneutralized one.     

粉煤灰超疏水不锈钢网的制备及油水分离

采用树脂粘接法,将硬脂酸修饰后的粉煤灰用环氧树脂粘接在不锈钢网骨架表面,制备了超疏水不锈钢网,并对其进行了TEM、SEM、FTIR和接触角等表征。结果显示：在高倍显微镜下改性后的超疏水不锈钢网表面呈一定粗糙度的微纳米分级结构,静态水接触角高达153°。此外,该超疏水不锈钢网具有良好的机械稳定性和超疏水耐久性,其表面经机械磨损试验100次后水静态接触角仍高达141°。该材料用于多种油/有机溶剂与水的混合液的分离中,分离效率均高于94%。     

类水黾脚部“凹凸沟壑”结构仿生超疏水涂层的制备与性能

以坡缕石粉为功能颜料,环氧树脂E-44和杜仲胶混合物为成膜物质,在涂有环氧/杜仲胶清漆的表面制备了一层具有类水黾脚部“凹凸沟壑”结构的仿生超疏水涂层。对涂层形貌和结构进行SEM、FTIR、XRD表征,对C3涂层（坡缕石粉质量分数为25%）进行水接触角、水滚动角、自清洁性能、抗润湿性能、耐磨性能、耐水性能等测试。结果表明,C3涂层表面具有明显的“凹凸沟壑”结构,其平均静态、动态水接触角为153.1°、152.6°,水滚动角为8.8°,具有优异的自清洁性能;C3涂层对泥土浆液、甲基橙溶液和亚甲基蓝溶液具有优良的抗润湿性,接触角均大于150°;C3涂层具有良好的基材适用性,涂覆于混凝土、织物棉布、纸张及塑料等表面均具有超疏水性能;经过载重为100 g的A4纸循环打磨50次,C3涂层水接触角依然高达151.9°,具有较好的耐磨性能;C3涂层在经过18和24 h浸泡后,其水接触角分别为152.2°和144.5°。     

A robust and coarse surface mesh modified by interpenetrating polymer network hydrogel for oil‐water separation

A robust and coarse surface mesh was fabricated by introducing a hydrogel coating with interpenetrating polymer network (IPN) structure on stainless steel mesh. The IPN hydrogel was prepared by crosslinking polymerization of acrylic acid (AA) followed by condensation reaction of polyvinyl alcohol (PVA) and glutaraldehyde (GA) at room temperature. As a result, the roughness of modified mesh was enhanced obviously and oil droplet underwater showed a larger contact angle. The hydrogel‐coated surface showed an underwater superoleophobicity with an oil contact angle of 153.92 ± 1.08^°. Besides, stable wettability was observed. The mesh can selectively separate oil from water with a high separation efficiency of above 99.8%. This work provides a facile method to strengthen the coating and enhance the efficiency of oil‐water separation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41949.     

Fabrication of superhydrophobic fabric coating using microphase‐separated dodecafluoroheptyl‐containing polyacrylate and nanosilica

Superhydrophobic coating was developed on cotton fabric in this article using a dodecafluoroheptyl‐containing polyacrylate (DFPA) and nanosilica. Film morphology of DFPA on cotton fibers/fabrics and chemical compositions of the treated cotton fabric were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), and X‐ray photoelectron spectroscopy (XPS), respectively. DFPA could form a relatively even film on the cotton fabric/fiber under SEM observation; however, it presented a rough and microphase‐separated pattern under AFM observation. There were many mountain‐like protuberances. The height of the protuberances and the root mean square roughness (R_ms) of the film reached about 20–50 nm and 12.511 nm in 2 × 2‐μm² scanning field (as the scale data was 100 nm). XPS analysis indicated that the perfluoroalkyl groups had the tendency to enrich at the film–air interface. DFPA could make the treated cotton fabric with a water contact angle (WCA) at about 138.5°. Cotton fabric was previously roughened using a 1 wt % silica sol with an average particle size of 20–30 nm and then finished by DFPA; hydrophobicity of the resultant cotton fabric was strongly improved, and WCA could reach 153.6°. The color of this superhydrophobic fabric would not be influenced, but its softness decreased compared to untreated fabric. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

A novel cyclic copolymer containing Si/P/N used as flame retardant and water repellent agent on cotton fabrics

A novel cyclic-shaped multifunctional copolymer named poly[tetra(tetramethylcyclosiloxyl-piperazin)-phosphinic acid methyl ether] (PNCTSi) was successfully synthesized. Its flame-retardant and hydrophobicity properties on cotton fabrics were investigated. The limited oxygen index (LOI) value of treated cotton fabrics with PNCTSi was up to 29.8%. By vertical burning test, it was found that the treated cotton fabrics have no after-flame and no after-glow. Apparently, more amounts of char were generated and hazardous volatiles distinctly reduce after combustion by thermogravimetric analysis. Besides, Treated cotton fabrics with PNCTSi can give a hydrophobic property, which reach a contact angle of 150°. The surface morphology of treated cotton fabric before and after combustion was analyzed by scanning electron microscopy, after burned, the surface morphology of cotton fiber exhibited more smooth and expanded feature. After washing the cotton fabric for 20 times, the LOI remains at above of 26.0%. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47280.     

Fabrication of two sites hydrophobicity on cotton surface – a fluoropolymerization approach

Cotton fabric on both surfaces was coated with polymerization of fluoromonomer followed by adsorption of fluorosurfactant by a new technique admicellar polymerization to obtain durable hydrophobicity. Water repellence properties were determined in terms of simple drop test contact angles. The coating on cotton fabric exhibited the right water contact angle of 137.23° and left contact angle 138.35° (an average value of 137.79°). However, the durability of the coatings was decreased after simple home laundering with a decrease in water contact angle value. The surface morphology was evaluated by scanning electron microscopy before and after polymerization. Beside this chemical composition on the cotton, the surface was evaluated by EDS analysis to determine the number of fluorine moieties deposited on the cotton surface by this technique.     

一种磁性-超疏水棉纤维的制备及性能

首先,将棉纤维浸泡在含有盐酸多巴胺(DA)和纳米Fe3O4的Tris-HCl缓冲溶液中制备得到聚多巴胺(PDA)-Fe3O4磁性棉纤维.其次,用十二烷基三乙氧基硅烷(DTES)在碱性的乙醇水溶液中对PDA-Fe3O4磁性棉纤维进一步改性,得到DTES-PDA-Fe3O4磁性-超疏水棉纤维.采用FTIR、XRD、TG、SEM、EDS、AFM、水接触角测量仪对改性前后棉纤维的化学组成、表面微观结构、疏水性能进行表征;测试了改性棉纤维分离效率、吸附性能.结果表明:DTES-PDA-Fe3O4改性棉纤维具有微/纳米尺寸粗糙结构;具有优异的超疏水性和磁性,水接触角大于160°;该棉纤维可重复使用且具有超高选择吸附性能和油水分离性能,可吸附自身质量8.96倍的氯仿,对氯仿油水混合液分离效率大于98.90％,可应用于生产生活中含油废水的处理.     

Facile ZIF‐8 functionalized hierarchical micronanofiber membrane for high‐efficiency separation of water‐in‐oil emulsions

The efficient separation and recovery of oil from water‐in‐oil emulsion poses a great challenge because of the rapid development of the petrochemical industry throughout the world. In this study, a facile method to develop a ZIF‐8 functionalized hierarchical micronanofiber membrane for high‐efficiency oil/water separation was investigated. The electrospun PVDF/ZnO membrane was made, on which ZIF‐8 crystal seeds were then created with the revitalizing step and expanded in the growth step, and finally functionalized hierarchical micronanofiber PVDF‐g‐ZIF‐8 membrane was obtained. Results showed that oleophilic ZIF‐8 crystals on the surface of PVDF membrane dramatically increased the wettability of oil and tuned PVDF membrane from olephobicity to oleophilicity. The hydrophobic/lipophilic PVDF‐g‐ZIF‐8 membrane with a water contact angle up to 158° and a toluene contact angle down to 0° provides its separation efficiency for water‐in‐oil emulsion of 92.93% in an environmentally friendly and energy‐saving manner. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46462.     

Robust Superhydrophobic Fabric for Durability,Self-Cleaning,and Oil/Water Separation via Thiol–Acrylate Polymerization

In recent years, highly efficient oil/water separation materials have brought much attention. It requests superhydrophobic surfaces with a rapid and facile separation process, excellent durability, and large-scale fabrication. Herein, a facile vapor-liquid sol-gel, and free radical polymerization reaction method to prepare the durable and robust superhydrophobic cotton fabric is proposed. Moreover, the fabric can be used for highly efficient and various oil/water separation. It is prepared via a simple two-step process, including a vapor-liquid sol-gel process to deposit with thiols particles, and then followed a free radical polymerization reaction to graft 2,2,3,4,4,4-hexafluorobutyl methacrylate. Scanning electron microscopy and Fourier transform infrared spectrometry prove that the rough structures are generated from the hydrolysis condensation reaction between tetraethyl orthosilicate and 3-mercaptopropyltriethoxysilane. As a result, the synthetic chemical composition provided by the natural fabric and silica nanoparticles synergistically construct a superhydrophobic surface with water contact angles and shedding angle of 158° and 9°, respectively. Additionally, the treated fabric exhibits excellent chemical resistance and self-cleaning ability. Remarkably, the fabric still retains superhydrophobic and excellent mechanical robustness after 30 cycles of various oil/water separation. In summary, the resultant fabrics with excellent chemical resistance, remarkable mechanical robustness, and versatile separation abilities have potential applications in various oil/water separations.     

Gradient and weather resistant hybrid super‐hydrophobic coating based on fluorinated epoxy resin

A weather resistant super‐hydrophobic coating that can offer good substrate adhesion and yet to be easily processed at large scale can be of practical use in emerging fields of self‐cleaning and anti‐icing paint, combing all these properties together remains challenging task. Here we describe a composite coating composed of a fluorinated epoxy resin emulsion with embedded in situ surface‐modified dual‐scale nano‐silica, which displayed durable super‐hydrophobicity and excellent adhesive strength. The as‐prepared coating possesses water contact angle of 158.6 ± 1°, sliding angle around 3.8 ± 0.2° which remain stable even under acidic/alkaline, heat/cool, and accelerated aging treatment. The results demonstrate that surface roughness had a micron‐ and nanometer scale distribution with increased particle loading beyond 40 wt %. Through quantitative comparison of surface Attenuated Total Reflection (ATR) with bulk FT‐IR transmission spectra, a gradient coating with surface enrichment of hydrophobic groups was determined. The air‐side fluorinated polysiloxane‐rich layer endows coating with weather‐resistance and ultra‐hydrophobicity while bottom epoxy resin layer enhances substrate adhesion. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40955.     

基于单宁酸制备可喷涂超疏水材料

通过正硅酸乙酯水解合成了二氧化硅纳米粒子并形成凝胶颗粒,加入单宁酸以优化其形貌,以六甲基二硅氮烷为表面改性剂,合成了具有低表面能的超疏水喷涂材料。并用动态光散射仪(DLS)与扫描电镜(SEM)对其表征。将其分散于乙醇,并对纸张、玻璃、铝箔、木板、棉质纺织物、塑料泡沫等常见表面进行喷涂,均在短时间内构成了超疏水表面,水接触角均在150.0°以上。随后,考察了所制备超疏水涂层在受外力破坏后的自修复性与耐磨性。结果显示:1 g/L的喷涂液仅需喷三层即可构建超疏水表面,得到的涂层具有良好的透明性;超疏水涂层在受外力损坏后可用有机溶剂进行快速简易的自修复;且喷涂后的玻璃片在砂纸上负重磨损距离达到1000 mm后,接触角从153.5°降至105.5°,再喷一层即可恢复到154.0°。