共溶剂性质对双亲性无规共聚物P(St-co-DM)胶束化行为及其性能的影响

Influence of Common Solvents on Micellization Behavior and Properties of the Amphiphilic Random Copolymer P(St-co-DM)

以苯乙烯（St）和甲基丙烯酸二甲氨乙酯（DMAEMA）为共聚单体，通过普通自由基溶液聚合合成了双亲性无规共聚物P（St-co-DM）.用傅里叶变换红外（FTIR）光谱、核磁共振氢谱（1H NMR）、凝胶渗透色谱（GPC）和差示扫描量热（DSC）仪对聚合物结构进行表征．研究了共溶剂的性质对P（St-co-DM）自组装胶束结构及其乳化性能的影响．用透射电镜（TEM）和动态激光光散射（DLS）表征了自组装胶体粒子的形态、粒径大小及其分布．通过测量胶束在甲苯，水界面的接触角表征胶束表面性能．结果表明：P（St—co-DM）以四氢呋喃（THF）为共溶剂自组装时，胶束的临界聚集水含量较大，胶束表面亲水性较强，流体力学半径较大：用二氧六环或THF为共溶剂，水为选择性溶剂，P（St-co-DM）自组装可以得到外层松散、内层比较密实的球状胶束，用N，N-二甲基甲酰胺（DMF）为共溶剂时，胶束整体呈现比较密实的球状胶束：分别用DMF、二氧六环和THF为共溶剂制备的胶束，其接触角均值都小于90°，可形成O／W型（水包油型）乳液．乳化实验结果表明，以二氧六环和THF为共溶剂制备的胶束作为颗粒乳化剂制备的乳液性能较好．

Styrene monomer （St） and dimethylaminoethyl methacrylate monomer （DMAEMA） were used to synthesize the amphiphilic random copolymer P（St-co-DM） via free radical copolymerization. The polymer structure was characterized by Fourier transform infrared （FTIR） spectroscopy, 1H nuclear magnetic resonance （1H NMR） spectroscopy, gel permeation in chromatography （GPC）, and differential scanning calorimetry （DSC）. We investigated the influence on the microstructure of the P（St-co-DM） nanoscale micelles by self-assembly in three common solvents （co-solvent）, and also investigated the effect of micelle structure on the emulsion properties. The morphologies and size distributions of the P（St-co-DM） colloid particles were studied by transmission electron microscopy （TEM） and dynamic light scattering （DLS）. The results show that the more critical water content, the higher hydrophilic and the bigger hydrodynamic radius of the micelles are observed when tetrahydrofuran （THF） is used as co- solvent. When dioxane or THF is used as co-solvent, the P（St-co-DM） self-assembles into spherical micelles with a relatively loose outer layer and a compact inner layer. In the case of N,N-dimethylformamide （DMF）, particles are distributed uniformly inside the spherical micelles. The hydrophilic properties of the micelles were characterized by recording the contact angle for the toluene/water interface. The contact angles of all the micelles are less than 90°. The O/W type （oil-in-water type） emulsions were obtained for three co-solvents. The type of emulsions was determined by drop test. The emulsifier experiment shows that the solid particulate emulsifiers have excellent emulsifying properties for dioxane and THF as co-solvents.