Study Of Preparation, Structure And Application Of The Monodispersed Polymer Microspheres

Monodispersed polymer microspheres with optimized characteristics have already found a broad range of fascinating applications in fields such as coating, adsorption materials for separation and drug delivery. The ability to assemble these microspheres into crystalline arrays allows one to obtain interesting and useful functionalities not only from the application of constituent materials but also from the fundamental physics of systems with the long-range, mesoscopic order that characterizes periodic structures. Colloidal crystal templating was one of the controllable and widely applicable methods to fabricate ordered porous materials. The main research contents and conclusions were divided into the following parts.1. Monodispersed P（St-MMA） microspheres were prepared by two-stage seed emulsion polymerization. The effects of reaction parameters such as temperature, content of monomers, content of emulsifiers and pH value on conversion, size and monodispersity of microspheres were investigated. When the concentration of emulsifiers based on water and the pH value were 0.1 wt.% and 7, respectively, monodispersed P（St-MMA） microsphere in the size range of 190nm-300nm could be obtained by changing the content of monomers in the second stage during polymerization process. The structure of the colloidal crystal also was investigated, the results indicated that P（St-MMA） colloidal crystal was face-centered-cubic （fcc） structure.2. P（St-MMA） colloidal crystal films were fabricated by the vertical deposition method at certain temperature and humidity. The effect of concentration of latex on the quality of colloidal crystal was investigated. And then the dynamic model of colloidal crystallization was established. When the concentration of latex was 0.2 wt.%, the quality of colloidal crystal film was optimal. The effects of annealing treatment conditions such as annealing temperature and time on the quality of colloidal crystal films were investigated. When the annealing temperature and annealing time were 75℃and 3h, respectively, the quality of colloidal crystal film was optimal. The surface property of colloidal crystal film also was investigated and the air cushion model of colloidal crystal film was established. The results indicated that the number of air cushion had strong influence on the surface property of colloidal crystal films.3. Monodispersed PS microspheres containing fluorine were prepared by two-stage seed emulsion polymerization in the presence of trifluoroethyl methacrylate （F₃MA） as a functional comonomer. The effect of F₃MA content on size and monodispersity of microspheres were investigated. The results showed that the size and monodispersity of microspheres decreased gradually with an increasing concentration of F₃MA. When the concentration of F₃MA based on monomers was 2.5 wt.%, the size and the coefficient of variation （C_v） of microspheres were 212nm and 4.2%, respectively. The surface property of PS colloidal crystal film containing fluorine also was investigated. When the concentration of F₃MA based on monomers was 2.5 wt.%, the colloidal crystal film exhibited high water-contact angles （121.3°）.4. Monodispersed P（St-AA） microspheres were prepared by two-stage seed emulsion polymerization. The effects of AA content on monodispersity of microspheres and quality of colloidal crystal films were investigated. When the concentration of AA based on monomers was 5.0wt.%, the monodispersity of microspheres and quality of colloidal crystal films were optimal. Micron-sized colloidal crystal balls prepared by utilizing a suspension system. The effect of carboxyl groups on the structure of the colloidal crystal balls was investigated. The results indicated that the sphericity, intensity and ordered degree of the colloidal crystal balls with carboxyl groups were better than that of colloidal crystal balls without carboxyl groups. The ordered porous SiO₂ balls were fabricated using P（St-AA） colloidal crystal balls as template. The ordered porous SiO₂ balls had a good sphericity, and the pores （with diameter of about 200nm） arrayed periodically.