Preparation And Performance Of Hydrophobic Polystyrene Photonic Crystal Films

Polystyrene (PS) photonic crystal (PC) with enhanced hydrophobicity was studied in this thesis. Order-arranged PS microspheres produced structural color, and modification of films or microspheres improved hydrophobicity, obtaining hydrophobicity enhanced and brilliance color PC films.Monodisperse PS microspheres were prepared by emulsion polymerization. The particle sizes were easily adjusted by changing the amount of emulsifier. The obtained samples were analyzed by Zeta-sizer and scanning electron microscopy (SEM), showing that PS were micro/nano spherical particles with uniform diameter (PDI<0.1) and stable emulsion (Zeta potential<-30mV).PS microspheres prepared by emulsion polymerization had anionic groups, and this was bad for the improvement of hydrophobicity. In this dissertation, low surface energy material was used to modify PS microspheres. Polydimethylsiloxane (PDMS) was dissolved in tetrahydrofuran (THF), and added into PS emulsion. Then the mixture was assembled by thermal-assisted self-assembly, obtaining hydrophobicity enhanced photonic crystal film in one step. Compared with the original films, contact angles of the obtained films were above135°, increasing by23-27°. At the same time, reflectivity of these films was higher than15%, demonstrating that PC films with high hydrophobicity and brilliance color were obtained.In view of the anionic groups on the surface of the microspheres, cationic surface active agent was designed to add into PS emulsion. Microspheres precipitated and accumulated, forming micron-sized protuberance. After dispersed with THF, the particles formed highly enhanced roughness film. Different charge of microspheres had little impact on hydrophobicity after precipitation. However, the amount of THF had great influence on hydrophobicity. With the increase of THF, contact angle of film increased at first, and then decreased. And the maximum contact angle reached159°and sliding angle was2°. The obtained superhydrophobic film met the requirements of self-cleaning materials.