Super-Hydrophobicity of Large-Area Honeycomb-Like Aligned Carbon Nanotubes

Abstract

Honeycomb-like aligned carbon nanotube films were grown by pyrolysis of iron phthalocyanine. The patterned structure was characterized by a scanning electron micrograph (SEM) and an atomic force micrograph (AFM). Wettability studies revealed the film surface showed a super-hydrophobic property with much higher contact angle (163.4 ( 1.4°) and lower sliding angle (less than 5°)sa water droplet moved easily on the surface. In contrast to a densely packed aligned carbon nanotube, the sliding feature was strongly affected by microstructure of surface.

Design of a Transparent Hydrophobic Coating

“…The methods that have been developed so far to impart roughness to solid surfaces include mechanical abrasion, 17) the addition of fillers (silica, 18) 22) pyrolysis, 56), 57) cutting, 58), 59) lithography, 60) and crystallization control. 61) Low surface energy is produced using coating, mixing, or polymerizing lowsurfaceenergy materials such as fluoro alkylsilane (heptadecafluorodecyltrichlorosilane, 30) perfluo rooctyltrichlorosilane 45) , heptadecafluorodecyltrimethoxysi lane, 20 48) .…”

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

“…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. [37][38][39][40][41][42][43][44][45] It has been well known that fractal structures can effectively magnify the real surface area compared with the projected one, and then enhance the wettability of a solid surface.…”

Superhydrophobic Carbon Nanotube Forests

“…Our observation may appear contradictory with experiments on tall carbon nanotubes grown off a substrate where superhydrophobicity has been observed. 18,19 Thus, we investigated taller (10-15 µm) nanotube forests, and these surfaces in the as-grown state did give an initial water contact angle of 161°. However, the droplets are not stable and eventually seep into the forest voids after a few minutes.…”