Temperature-responsive hydrogels have been widely developed for biomedical applications. In this study, 4-benzyloxy-ε-caprolactone (CL-OBn) was synthesized and the subsequent ring opening polymerization (ROP) of ε-caprolactone (CL) and CL-OBn monomers was performed by using the hydroxyl group of methoxy polyethylene glycol (MPEG) in the presence of HCl·Et₂O as a monomer activator. MPEG-b-poly (ε-caprolactone) (MC) with benzyl pendant groups (MC-OBn) was successfully obtained in almost quantitative yield and the segment ratios and molecular weights were close to the theoretical values. Deprotection of the benzyl pendant groups successfully provided MC with hydroxyl pendant groups (MC-OH). Suspensions of MC-OBn and MC-OH exhibited distinct sol-to-gel phase transitions as a function of the temperature. The sol-to-gel phase transition of the MC-OBn and MC-OH diblock copolymers depended on the type (benzyl or hydroxyl) and amount of pendant groups in the diblock copolymer structure. The pendant group on the MC-OBn and MC-OH diblock copolymers either stabilized and/or destabilized hydrophobic aggregation between the MC segments. The hydrophobic aggregation was confirmed by the detection of crystallinity in the MC-OBn and MC-OH diblock copolymer suspensions. In conclusion, MC-OBn and MC-OH diblock copolymers were successfully prepared and served as temperature-responsive hydrogels.

温度响应型水凝胶已被广泛开发用于生物医学应用。在这项研究中，合成了4-苄氧基-ε-己内酯（CL-OBn），随后使用甲氧基聚乙二醇的羟基进行了ε-己内酯（CL）和CL-OBn单体的开环聚合（ROP） （MPEG）在HCl的Et·存在₂ O作为单体活化剂。MPEG- b以几乎定量的产率成功地获得了具有苄基侧基（MC-OBn）的β-聚（ε-己内酯）（MC），其链段比和分子量接近于理论值。苄基侧基的脱保护成功地为MC提供了羟基侧基（MC-OH）。MC-OBn和MC-OH的悬浮液表现出明显的溶胶-凝胶相变，是温度的函数。MC-OBn和MC-OH二嵌段共聚物的溶胶-凝胶相变取决于二嵌段共聚物结构中侧基的类型（苄基或羟基）和数量。MC-OBn和MC-OH二嵌段共聚物上的侧基可稳定和/或不稳定MC链段之间的疏水性聚集。通过检测MC-OBn和MC-OH二嵌段共聚物悬浮液中的结晶度来确认疏水性聚集。总之，成功制备了MC-OBn和MC-OH二嵌段共聚物，并用作温度响应型水凝胶。