PVP-assisted synthesis of raspberry-like composite particles

Abstract

Composite particles composed of SiO2 nanoparticles and polystyrene (PS) spheres with a raspberry-like structure were successfully synthesized by a PVP-assistant sol–gel method. The as-prepared products were systemically characterized by FT-IR, TGA, SEM and TEM. The characterization results indicated that the amount of polyvinyl pyrrolidone (PVP) and concentration of ammonia solution played key roles in tailoring the structure of the composite particles, including size and surface density of SiO2 nanoparticles on the surface of PS spheres. During the PVP-assisted sol–gel process, the synthesized nano-sized SiO2 particles were favorably deposited on the surface of PS spheres to form hierarchical composite particles. By adjusting the amount of PVP and pH value of reaction system, the typical raspberry-like particles with controllable coverage of SiO2 nanoparticles on PS spheres were obtained. Subsequently, the composite particles with well controllable morphology were modified with OcTMS and orderly deposited on the substrate. The effect of the composite particles with different morphologies on the wetting property was investigated. Finally, superhydrophobic surface was generated and the water contact angle was up to 154°. PS–SiO2 composite particles with hierarchical structure were successfully prepared by a PVP-assisted sol–gel method, which exhibited a superhydrophobic property after surface modification with OcTMS.