Fabrication of super-hydrophobic film with dual-size roughness by silica sphere assembly

Two simple approaches were developed for the fabrication of super-hydrophobic film with dual-size roughness by taking advantage of assembling silica micro- and narrospheres. Electrostatic adsorbing technique and template-directed self-assembly were used here. The dual-size surface, which mimics the surface topology of lotus leaves, comprises both the micro-scale and nano-scale roughness. After the roughened surface was chemically modified with a layer of fluoroalkylsilane, super-hydrophobicity with a water contact angle higher than 160 degrees and sliding angle as low as 0.5 degrees can be achieved. The simplicity and cheapness of this procedure may make widespread applications of this super-hydrophobic film possible. (c) 2006 Elsevier B.V. All rights reserved.