Additive particles having superhydrophobic characteristics and coatings and methods of making and using the same

Abstract

Additive particles may be employed in sufficient amounts to impart superhydrophobicity to a coating system in which the additive particles are incorporated. The additive particles include carrier microparticles and a dense plurality of nanoparticles adhered to the surfaces of the carrier microparticles (e.g., preferably by electrostatic deposition or covalent bonding). The additive particles are advantageously incorporated into a coating material (e.g., a polymeric material) in amounts sufficient to render a substrate surface superhydrophobic when coated with the coating material. The substrate may be rigid (e.g., glass, ceramic or metal) or flexible (e.g., a polymeric film or sheet or a fabric). In some preferred embodiments, both the microparticle and nanoparticles are formed of silica and are surface treated with a hydrophobic treatment so as to impart superhydrophobic properties thereto. Especially preferred are particles treated with silicone fluid comprised of a polysiloxane and/or a perfluoro silane having between 1 and 40 carbon atoms.