两亲性PS-b-PEG-b-PS三嵌段共聚物的合成及在水中的聚集行为研究

Synthesis and aggregation behaviour of amphiphilic PS-b-PEG-b-PS triblock copolymers in aqueous solution

采用原子转移自由基(ATRP)合成了一系列两端为短的聚苯乙烯(PS)嵌段,中间为长的聚乙二醇(PEG)嵌段的PS-b-PEG-b-PS两亲性三嵌段共聚物。采用1H-NMR、荧光探针法和动态光散射研究了PS和PEG嵌段长度对三嵌段共聚物在水中聚集行为的影响。结果表明:三嵌段共聚物在水中可以形成以PS嵌段为核和以PEG嵌段为壳的球形胶束,其胶束化的临界胶束浓度(CMC)随着PS嵌段长度增加而减小,流体力学半径(Rh)随PEG嵌段长度增长而增大,调整PS嵌段长度能有效地调控胶束的形成。胶束对疏水分子芘具有很好的装载能力,芘在胶束中的分配平衡常数(Kv)为105,随PS嵌段长度增加而增大。

The amphiphilic polystyrene-b-poly（ethylene glycol）-b-polystyrene（PS-b-PEG-b-PS） triblock copolymers with well-defined structure were synthesized by atom transfer radical polymerization（ATRP）.The aggregation behavior of these triblock copolymers in aqueous solution were examined by 1H-NMR,fluorescence excitation spectra of pyrene probe,dynamic light scattering（DSL） and transmission electron microscopy（TEM）.The core-shell micelle with hydrophobic PS core and hydrophilic PEG loop chain corona was formed in aqueous solution.The critical micelle concentration（CMC） decreased with increasing PS block length,The hydrodynamic radius Rh increased with increasing PEG block length.Increasing hydrophobic PS block length effectively promoted the micelle formation in aqueous solution.The partition constant Kv of pyrene in the micelle was about 105 and increased with increasing PS block length.