Superhydrophobic and transparent coatings based on removable polymeric spheres

Abstract

Superhydrophobic and also highly transparent coatings can be prepared by a sol-gel dip-coating method. Polystyrene spheres (PSs) are used as a removable template and the coatings have a volcano-like micro/nano structure. The micrometer-sized pinnacles form by the assembly of PSs and silica particles, whereas the nanometer-sized peaks on individual pinnacles are created by the removal of PSs. Due to this particular structure the contact angle of a 4 µL water droplet on the prepared coating can reach 160° with the corresponding sliding angle being close to 0°. Additionally, the transmittance of the coated glass is as high as the uncoated glass.