Superhydrophobic and oleophobic surfaces obtained by graft copolymerization of perfluoroalkyl ethyl acrylate onto SBR rubber

Superhydrophobic and oleophobic rubbery coatings were prepared by spraying perfluoroalkyl ethyl acrylate (Zonyl TA-N) grafted styrene butadiene rubber (SBR) solution in toluene after addition of hydrophilic and hydrophobic fumed silica powders onto glass. Grafting onto SBR has been performed by free radical copolymerization in toluene using different Zonyl TA-N feed compositions. Molecular weights of the graft copolymers were determined by GPC and intrinsic viscosity measurements. Thin films of Zonyl TA-N grafted SBR copolymers were prepared by dip coating glass slides into toluene solutions of SBR-g-Zonyl TA-N with varying fluoromonomer contents and their surface free energies were determined by contact angle measurements. The increase in Zonyl TA-N content resulted in a considerable decrease of the total surface free energy of the grafted SBR film. Later, superhydrophobic and oleophobic surfaces were prepared by adding hydrophilic and hydrophobic fumed silica powders into graft copolymer solutions and spraying onto glass. The effect of the Zonyl TA-N content in the graft copolymer, type of silica and its weight concentration in the solution on the water and hexadecane contact angle values, on the surface morphology and mechanical durability of the coatings were investigated. The highest water contact angle of the SBR-g-Zonyl TA-N/SiO2 hybrid coatings was determined to be 162 degrees and hexadecane contact angle 147 degrees after adjusting the silica type, solids content and fluoroacrylate/SBR composition of the graft copolymer spray solution. (C) 2015 Elsevier B.V. All rights reserved.