Superhydrophobic polystyrene layers filled with silica on glass

Wetting properties of polystyrene (PS) films with silanized colloidal silica particles as the filler deposited on glass were investigated. The PS powder was dissolved in chloroform and defined amount of the silica was dispersed with a sonicator. The silica particles were silanized to different surface fraction coverage v, that is, v: 1.00, 0.93, 0.68, 0.42 and 0.16. The PS-silica films were then deposited by self-spreading or spin coating and dried at room temperature for 24 h in an open air or in a vacuum. Water advancing and receding contact angles were measured on prepared films by tilted plate method. As high as 150 degrees advancing contact angles were measured for films composed of highly hydrophobic silica. Using the measured advancing and receding contact angles, the film apparent surface free energy was calculated and for the superhydrophobic PS-silica film, v = 0.68, the energy was smaller than 3 mJ/m(2). It has been concluded that produced PS films may have practical applications because the polystyrene glue adheres strongly to many solid supports. Such films may also play a role in anticorrosion protection.