复乳法制备大孔聚合物微球

Preparation of Macroporous Polymer Microspheres by Double-emulsion Method

研究在不使用乳化剂和致孔剂的条件下采用两亲性聚合物单甲氧基聚乙二醇聚乳酸共聚物制备大孔微球,确定了形成大孔结构的必要条件及孔径的控制方法,并对大孔微球的形成机理进行了探讨.结果表明,两亲性聚合物单甲氧基聚乙二醇聚乳酸共聚物能较好地稳定乳液进而形成贯穿孔结构,而选用疏水性聚合物聚乳酸和聚(乳酸-羟基乙酸)时只能制备出单腔室结构的微球;当内水相与油相体积比在1:4～1:2、油相溶剂去除分两步时,能形成孔径在100nm以上的大孔聚合物微球,大孔微球的孔径随着初乳化速率的增大而减小.

Amphiphilic copolymer, monomethoxy-poly（ethylene glycol）-b-poly-dl-lactide （PELA）, was used to prepare macroporous microspheres without adding any emulsifier or porogen, and the necessary preparation conditions for formation of macroporous microspheres and their effects on pore diameter were studied. The results indicated that stable emulsions and macroporous structure were prepared by PELA, but hydrophobic poly（lactic acid） and poly（lactide-co-glycolide） could only produce microcapsules, It was found that macroporous microspheres with the pore diameters more than 100 nm could be produced while the volume ratio of inner water phase to the volume ofoil phase was between 1：4-1：2, and the microspheres were solidified through two steps. The results showed that the pore diameters of macroporous microspheres decreased as the primary emulsification rate increased. In addition a possible mechanism of the formation of macroporous microspheres was proposed.