Strong Amphiphobic Porous Films with Oily-self-cleaning Property beyond Nature

Abstract

The lotus leaf is known as one of the natural self-cleaning plants, which can easily roll off water but not oil droplets. Herein, a simple chemical bath deposition method to fabricate superhydrophobic and strong oleophobic surfaces was presented on porous substrates such as fabrics and nickel foams. The resultant substrates exhibited excellent superhydrophobicity and good oil repellency. More significantly, such surfaces possessed self-cleaning property for water, as well as to oils such as glycerol and rapeseed oil.In nature, many surfaces are superhydrophobic with water contact angles larger than 150°and sliding angles lower than 10°. Lotus leaves, rice leaves, and cicada wings are some representative surfaces with superhydrophobic properties, which generally represent in the form of self-cleaning.1 However, such a self-cleaning effect will be deteriorated by various degrees when the surface is contaminated by oily waste liquids in practical applications. 2 Although superoleophobicity has been found in the case of fish scale and shark skin in nature, such oil repellency exists only underwater. There are very few reports on oil repellency in air, 3 because the lower surface tension of oil makes the lyophobicity harder achieve than in the case of water. 4 Therefore, it is urgent, necessary, and challenging to design and fabricate superhydrophobic surfaces with antioily contamination for industrial applications.To achieve these properties, improving the oleophobicity of superhydrophobic surfaces is of utmost significance. It is well known that wettability is governed by both the chemical composition and geometric structure of a solid surface. 5According to three models that describe the contact angle of a droplet on a surface, 68 lower surface energy and proper roughness are necessary for achieving superoleophobic surface. In general, some special structures such as a re-entrant or overhanging geometries are indispensable to obtain appropriate roughness for superoleophobicity. 911 Besides, fluorinated chemicals with extremely low surface energies, such as perfluoroalkylthiol and perfluorinated silane, are also essential to obtain a superoleophobic surface. So far, only a few of methods have been developed to fabricate both superhydrophobic and superoleophobic surfaces (also called superamphiphobic) on various substrates, including electrochemical method, 12 electrodeposition, 13 and so on. 1416 Superoleophobic surface on a metal substrate has been widely reported because of the facile construction of roughness by chemical etching and deposition. 17Superoleophobic fabrics have also been prepared by using the multiscale structure concept. 18 Moreover, a self-healing superamphiphobic surface has been obtained by coating the fluorocontaining polymers on the fabric.19 Compared to the conventional superhydrophobic surface, 2023 these as-prepared surfaces with superhydrophobictiy and strong oleophobicity are exciting since a great progress has been made on lowering the surface free energy and constructing more fine su...

Design, Development, and Outlook of Superwettability Membranes in Oil/Water Emulsions Separation

“…Furthermore, textiles/fabrics have high porosity with easy modification and environmental friendliness, therefore, the modified textile/fabric‐base membrane would be a good choice for oil/water emulsion separation. So far, a large number of superhydrophobic textiles/fabrics have been successfully prepared through various methods, such as one‐step electrospinning method by controlling morphology and composition, [ 118,119 ] LBL method, [ 120,121 ] chemical vapor deposition, [ 122,123 ] plasma treatment, [ 124,125 ] hydrothermal treatment, [ 126,127 ] spraying method, [ 128,129 ] dip coating, [ 130,131 ] wet chemical deposition, [ 132,133 ] electro‐assisted chemical deposition, [ 134,135 ] sol–gel [ 136,137 ] and polymer grafting. [ 138,139 ]…”

Recent developments of bioinspired materials with superwettability

“…曾等 [78] 通过沉积CuO在织物或泡沫多孔基底上, 后经过氟化硫醇修饰得到具有疏水疏油的海绵和织 了原始的超双疏性能. 姜等 [82] 在固体Al基底上通过化 学刻蚀和氟化修饰剂全氟癸基三氯硅烷得到超双疏铝 图 6 仿生荷叶表面的结构, 构筑的类荷叶结构的超双疏表 面 [80] (网络版彩图) )).…”

Recent Progress in Fabrication and Applications of Superhydrophobic Coating on Cellulose-Based Substrates

“…Zeng et al reported a simple chemical bath deposition method to deposit CuO nanoparticles on fabric [ 69 ]. The as-prepared fabric exhibited superhydrophobicity and highly oleophobicity after a fluorination process as shown in Figure 4 a–d.…”

“… ( a ) Schematic diagram of the fabrication process for strong amphiphobic fabric; ( b ) SEM images of the original fabric; ( c,d ) Low- and high-magnified images of the CuO-coated fabrics (Reprinted from Reference [ 69 ] with permission); ( e ) Schematic illustration of the procedure used to construct superhydrophobic TiO 2 particles-decorated cotton fabric and their corresponding SEM images and wetting behaviour before and after TiO 2 particles-decoration and 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane modification. (Reprinted from Reference [ 70 ] with permission).…”