标题：Fabrication of macroporous foam and microspheres of polystyrene by Pickering emulsion polymerization
作者：Xiaona Li;Chunli Zhu;Yanze Wei
作者机构：[Li, X] Key Laboratory for Special Functional Aggregated Materials of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong Un 更多
通讯作者地址：[Lu, ZJ]Shandong Univ, Sch Chem & Chem Engn, Minist Educ, Key Lab Special Funct Aggregated Mat, Jinan 250100, Peoples R China.
来源：Colloid and polymer science
关键词：Pickering emulsions;Macroporous polystyrene foam;Polystyrene microspheres
摘要：Poly(styrene-co-methacrylic acid) (PS-co-MAA) particles were synthesized via surfactant-free emulsion polymerization and then used as particulate emulsifiers for preparation of Pickering emulsions. Our results showed that adjusting the solution pH can tune the wettability of PS-co-MAA particles to stabilize either water-in-oil (W/O) or oil-in-water (O/W) Pickering emulsions. Stable W/O emulsions were obtained with PS-co-MAA particles at low pH values due to their better affinity to the dispersed oil phase. In contrast, increasing the pH value significantly changed the stabilizing behavior of the PS-co-MAA particles, leading to the phase inversion and fonnation of stable O/W emulsions. We found that the oil/water ratio had a significant influence on pH value of the phase inversion, It decreased with decreasing the oil/water ratio, and no phase inversion occurred when the styrene volume fraction reduced to 10 %. Additionally, macroporous polystyrene (PS) foam and PS microspheres were obtained via polymerization of Pickering high internal phase emulsion (Pickering HIPE) and O/W Pickering emulsion, respectively.