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 PDDA/sodium silicate multilayer film leads to the formation of a micro- and nanostructured hierarchical surface. After chemical vapor deposition of a layer of fluoroalkylsilane, a superhydrophobic surface with a water contact angle of 157.1 degrees and sliding angle of 3.1 degrees 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.