Synthesis of Superhydrophobic Raspberry-Like Polymethylmethacrylate/Silica Core/Shell Particles
Silica-coated raspberry-like polymeric particles were synthesized based on the cationic colloidal particles which were prepared by soap-free emulsion polymerization of methylmethacrylate (MMA) in the presence of a cationic monomer, methacryloxyethyltrimethyl ammonium chloride (MOTAC) using azobis(isobutylamidine)hydrochloride (AIBA) as an initiator. The Stöber method has been adopted to coat silica on the surface of these cationic particles. Negatively charged Silica precursors were rapidly hydrolyzed onto the cationic surfaces of colloidal particles. The resulted polymethylmethacrylate-silica(PMMA-silica) core-shell particles were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which clearly revealed that the PMMA-silica core-shell particles had the raspberry-like structure with 45nm wall thickness. Then, the fabrication of a superhydrophobic particle surface was achieved by coupling reaction of the PMMA-silica core-shell particle surface with nonafluorohexyltriethoxysilane. The water and oil static contact angle on the surface of the submicron-nano particles were 161° and 129°, respectively.
S. Suttiruengwong and W. Sricharussin
H. S. Hwang et al., "Synthesis of Superhydrophobic Raspberry-Like Polymethylmethacrylate/Silica Core/Shell Particles", Advanced Materials Research, Vols. 93-94, pp. 27-30, 2010