Layer-by-layer deposition of poly(diallyldimethylammonium chloride) and sodium silicate multilayers on silica-sphere-coated substrate-facile method to prepare a superhydrophobic surface

A facile method for preparing a superhydrophobic surface was developed by layer-by-layer (LbL) deposition of poly(diallyldimethylammonium chloride) (PDDA)/sodium silicate multilayer films on a silica-sphere-coated substrate followed with a fluorination treatment. First, a silica-sphere-coated substrate that contains loosely stacked silica spheres of 600 and 220 nm was prepared and cross-linked with SiCl₄. PDDA was then alternately assembled with sodium silicate on the silica-sphere-coated surface to prepare a micro- and nanostructured hierarchical surface. Scanning electron microscopy (SEM) images verify that the deposition of a 5-bilayer FDD A/sodium silicate multilayer film leads to the formation of a microand nanostructured hierarchical surface. After chemical vapor deposition of a layer of fluoroalkylsilane, a superhydrophobic surface with a water contact angle of 157.1° and sliding angle of 3.1° was successfully fabricated. The easy availability of the materials and simplicity of this method might make the superhydrophobic surface potentially useful in a variety of applications.