Environmentally Stable Super Water‐Repellent Poly(alkylpyrrole) Films

Abstract

Repellent films: Poly(alkylpyrrole) conductive films with a water contact angle larger than 150° are stable to temperature, organic solvents, and oils and are super water‐repellent. The surface of the film is a fractal and consists of an array of perpendicular needle‐like structures (see picture; inset: digital camera image of a water droplet on the film).

Super water-repellent poly(alkylpyrrole) films having environmental stability

“…The contact angle of the film was nearly constant even when the treating temperature increases, as shown in Fig. 10 and the inset therein [31].…”

“…The surface of the array of the polyacrylonitrile nanofibrils showed super water-repellency with a contact angle of larger than 150 o [10]. Martin et al first reported a template-guiding synthesis of polypyrrole microtubes [31]. They synthesized an array of polypyrrole microtubes electrochemically by using a porous polycarbonate membrane as a template [31].…”

Fabrication of superoleophobic hierarchical surfaces for low-surface-tension liquids

“…It has often been reported that fractal surfaces are the most effective for superhydrophobicity. [5][6][7][8][9][10][11] Compared with the extensive investigations of superhydrophobic surfaces, studies on superoleophobic surfaces are still limited due to the difficulty of repelling liquids with low surface tension, such as liquid alkanes and alcohols. This arises from the fact that most solid surfaces, including fluoroalkyl-coated surfaces with surface tension of ~6 mN m −1 , are oleophilic, and the contact angles for low-surface-tension liquids on the flat surfaces are usually less than 90º.…”

Formation mechanism of super water-repellent fractal surfaces of alkylketene dimer

“…In the former trial, fluorinated compounds with low surface energy were usually used, while several nano-or micro-textured or fractal structures on the surfaces were formed in the later case. Various approaches to prepare super water-repellent surfaces have been reported including melt-solidification of a wax, [11][12][13][14] silica and oxidized alumina films through the sol-gel method, [15][16][17] plasma-based etching or deposition, 18,19 gel-like roughened polypropylene, 20 anodically oxidized aluminum, 21,22 etched copper and electrodeposited copper, 23 electrochemical polymerization, 24 layer-by-layer assembly together with electrodeposition, 25 solution-immersion, 26 polymer/nanoparticle composite films, 27,28 films of aligned carbon nanotubes, polymer nanofibers and inorganic nanorods. [29][30][31][32][33][34][35][36] Effects of geometric length scales, surface roughness and surface energy on the wettability of super water-repellent surfaces were extensively discussed from physical and chemical points of view.…”

“…[11][12][13]21,22,46 Alkylketene dimer (AKD), a kind of wax, was found to form fractal structures spontaneously with a dimension of 2.29 and to give super water-repellent surfaces with the water contact angle as large as 174 o . 11,12 Super water-and oil-repellent surfaces 21,22 with fractal dimension of 2.19 and fractal super water-repellent poly(alkylpyrrole) film 24 with a dimension of 2.23 were also successfully made. Because of the fractal structures and super water-repellent properties, the AKD surfaces have attracted much attention.…”