嵌段共聚物P(MAn-alt-St)m-b-PStn的制备及其水解物的自组装研究

采用可逆加成-断裂链转移（RAFT）聚合方法合成了苯乙烯和马来酸酐的交替嵌段共聚物P(MAn-alt-St) _m-b-PSt_n，通过核磁共振仪（NMR）、凝胶渗透色谱仪(GPC)对聚合物进行了表征，确认3种不同交替段/均聚段(m/n)比例的嵌段共聚物组成分别为P(Man-alt-St)₄₉-b-PSt₇₀，P(MAn-alt-St)₄₈-b-PSt₉₇和P(MAn-alt-St)₅₀-b-PSt₁₃₁。将所制备的交替嵌段共聚物在碱性水溶液中水解后得到了两亲性嵌段共聚物，用扫描电镜（SEM）对两亲性共聚物的自组装形貌进行了研究，结果表明随着两亲性共聚物中PSt均聚段比例的增加，自组装形成的胶束形貌出现由分散的类棒状到支化状再到密集的网状转变。

Preparation of the block copolymer P(MAn-alt-St)m-b-PStn and the self assembly behaviour of its hydrolysate

Alternating block copolymers of styrene and maleic anhydride (P(MAn-alt-St) _m-b-PSt_n) have been synthesized in a one pot reaction by reversible addition-fragmentation chain transfer (RAFT) polymerization, and the resulting copolymers were characterized by nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC). Three block copolymers with different alternating copolymer segment homopolymer segment ratios were obtained: P(Man-alt-St)₄₉-b-PSt₇₀, P(MAn-alt-St)₄₈-b-PSt₉₇ and P(MAn-alt-St)₅₀-b-PSt₁₃₁. The copolymers were hydrolyzed with KOH aqueous solution to obtain the amphiphilic block copolymers, and the self assembled morphologies of the amphiphilic block copolymers were characterized by scanning electron microscopy. It was found that as the proportion of PS homopolymer segment increased in the amphiphilic polymer, the morphologies of the self assembled aggregates changed from dispersed rods to branched aggregates and then to dense meshes.