两亲性嵌段共聚物PEO-b-PMMA的合成及其在水溶液中的自组装

Synthesis of amphiphilic block copolymers of poly( ethylene oxide)and poly( methyl methacrylate)( PEO-b-PMMA) and their self-assembly in solution

以PEO-Br为大分子引发剂,通过原子转移自由基聚合合成了两种具有不同疏水链长的PEO-b-PMMA两亲性嵌段共聚物,经GPC和1H-NMR表征确认其结构分别为PEO45-b-PMMA130和PEO45-b-PMMA335。以二氧六环作为初始共溶剂,考察了PEO-b-PMMA在水溶液中的自组装,用光散射和透射电子显微镜对共聚物的临界加水量和聚集体的形貌进行了测定与表征;结果表明随着PMMA链段的增长,临界加水量由27.5%降为22.5%,球形聚集体的平均粒径由44 nm增至76 nm。

Two kinds of amphiphilic block copolymers PEO-b-PMMA were synthesized by atom transfer radical pol- ymerization using PEO-Br as the macroinitiator. Well defined copolymers PEO45-b-PMMA130 and PEO45-b-PMMA335 were characterized by GPC and H-NMR. Self-assembly of PEO-b-PMMA in solution was investigated using dioxane as the initial common solvent. The critical water content and the aggregate morphology were characterized by light scattering and transmission electron microscopy. The results indicate that when the length of the PMMA block was increased, the critical water content decreased from 27.5% to 22.5% , and the average size of the spherical aggre- gates increased from 44 nm to 76 nm.