Preparation Of Monodisperse Polystyrene Nanospheres In Confined Space

By taking the advantage of confined space to prepare the monodisperse polystyrene (PS) nanospheres. The confined space involve the nanoreactor developed from the selfassembly of amphiphilic copolymer, the soap-free emulsion polymerization system and Pickering emulsion polymerization. The products were characterized and the results were discussed.The poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol) terminated with pentacyano(4-(dimethylamino)-pyridine) ferrate (EPE-Fe) complex surfactant was synthesized and self-assembled with styrene (St) in water to form a nano-reactor (EPE-Fe-St). And the polystyrene nanospheres (EPE-Fe-PS) were prepared through free radical polymerization in the nano-reactor. Furthermore, ferric ion was used to cure the shell of the EFE-Fe-St to form a hardened nano-reactor (Fe-EPE-Fe-St). The styrene polymerization was also arisen in the nano-reactor to form polystyrene nanospheres (Fe-EPE-Fe-PS) with a hardened shell. The results of molecular weight and morphology of polystyrene nanospheres show that the various size of monodispersed polystyrene nanospheres in 80-120 nm have been obtained. The effect of polymerization temperature on the size of self-assembled EPE-Fe-St is remarkable, and on the size of the Fe-EPE-Fe-St is slight. The higher molecular weight of the polystyrene has achieved more than 700,000 in the confine space. In the self-assembled nano-reactor, the molecular weight of PS decreases with increase of initiator content in St and enhancement of polymerization temperature, and increases with augment of EFE-Fe content in water. The glass transition temperature (Tg) of the polystyrene nanospheres prepared in two kinds of the confined space are in the range of 90-135℃. The Tg of polystyrene nanosphere is enhanced after hardening the shell of nano-reactor whether St was polymerized in the confined space with harden shere or not.Sodium p-styrenesulfonate(SSS) was used to get the soap-free emulsion system for the production of polystyrene spheres, and this system was named with SSS-PS system. The results show that monodisperse polystyrene spheres have been produced and the size of the spheres ranges from 70nm to 700nm. To modulate the size of the polystyrene nanospheres developed from SSS-PS system, the nanosize silica sol (NanoSiO2) was introduced into the former SSS-PS system to get another hybrid system:NanoSiO2-SSS-PS system. Both of these two systems could get monodisperse polystyrene spheres with various sizes for changes of the parameters. In the SSS-PS system, the diameter of spheresdecrease with the increase of the amount of SSS without change of the dispersibility. At the same time, the molecular weight of polystyrene decreases with the increase of the amount of SSS as well, and the diameter of polystyrene spheres decrease with the increase of amount of initiator. However, the effect of initiator on the spheres is not as evident as SSS.After the introduction of nanosize silica sol, the sizes of products decrease with the increase of the amount of nanosize silica sol, that means the size of polystyrene could be modulated through the change of amount of nanosize silica sol. DSC results show that the introduction of SSS into the polystyrene increases the glass transition temperature (Tg), and with the increase of the amount of SSS, the glass transition temperature (Tg) could even get to 120℃.