酶促开环聚合合成双亲性H型嵌段共聚物及其自组装

Chemoenzymatic synthesis amphiphilic H-shaped copolymer and its self-assembly behavior

通过固定化酶Novozyme435(NV435)催化聚乙二醇(PEG)开环聚合己内酯(CL)得到端基带有羟基的ABA型三嵌段聚合物,用2,2-二氯代乙酰氯将聚合物的端羟基功能化形成H型大分子引发剂,在CuCl/HMTETA体系中引发4-乙烯基吡啶(4VP)进行原子转移自由基聚合反应(ATRP),得到了具有两亲性的H型五嵌段聚合物(PVP)2-b-PCL-b-PEG-PCL-(PVP)2,用红外光谱(FT IR),核磁共振(1H NMR),凝胶渗透色谱(GPC)对其结构与分子量及其分子量分布进行了表征,结果表明:H型五嵌段聚合物分子量46121g/mol,分子量分布1.30.并利用动态光散射(DLS)和原子力显微镜(AFM)对聚合物在水溶液中的自组装行为进行了研究,H型嵌段聚合物的胶束呈球形结构,平均直径为70nm左右.

ABA triblock copolymers were synthesized by dihydroxyl-capped PEO initiated enzymatic ring-opening polymerization （cROP） of ε-CL in the presence of biocatalyst Novozyme 435. The chains ended with hydroxyl of block copolymers were modified by the esterification of 2,2-dichloro acetyl chloride （DCAC） to obtain the tetrafunctional macroinitiator, which was used in the ATRP of 4-vinylpyridine （4-VP）. CuCI/HMTETA was used as the catalyst system in the ATRP of 4-VP to acquire the H-shape block co-polymers （PVP）2-b-PCL-b-PEG-b-PCL-b-（PVP）2. The H-shaped block copolymers were characterized by FTIR, NMR, and GPC. Copolymers with high molecular weights （Mn = 46121 g/mol） and low polydispersities （Mw/Mn = 1.30） were prepared. Moreover, the morphology of the copolymer was examined with dynamic light scattering （DLS） and atomic force microscopy （AFM）. Spherical micelles with a diameter of 70 nm in aqueous solution were obtained.