探索构建具有好的力学性能和稳定性，又能自愈合以及溶胶-凝胶转变的动态共价键智能水凝胶的研究对其在生物医学等领域的应用具有重要意义。本项目提出在动态共价键凝胶单一网络中引入氢键基元，以及能够微区温度诱导形成胶束并“封装”动态共价键的机制用于构建具有上述性能的智能水凝胶的思路。拟通过可逆加成—断裂链转移聚合制备形成氢键且两末端嵌段具有温敏特性并含酮羰基或酰肼基五嵌段聚合物；将两者复合，通过pH调控酮羰基和酰肼基之间酰腙键的形成或断裂，使体系发生溶胶-凝胶转变；在酰腙键成键下，通过温度诱导温敏嵌段形成胶束，并“封装”动态共价键，实现凝胶力学性能的提高；降低温度，其又具有可逆性。通过凝胶性能评价和内部微观结构的分析，揭示其智能响应的机理，构建分子结构—刺激因子（pH和温度）—凝胶网络结构—凝胶力学性能、稳定性、自愈合以及sol-gel转变能力之间的内在科学关系，为它潜在的应用提供理论和基础数据。

It is of great significance to explore the construction of smart hydrogels with good mechanical properties and stability, self-healing ability and sol-gel transition for their application in biomedicine. In this proposal, resorting to the introduction of hydrogen bonding and the formation of micelles which encapsulate the dynamic covalent bonds in microdomains under temperature trigger, the smart hydrogel with the abovementioned properties will be prepared. We will firstly synthesize well-defined five block copolymers by reversible addition-fragmentation chain transfer polymerization (RAFT). As for the five block copolymers, the hydrogen bonding can form between the three middle blocks, and the ending blocks contain ketone or hydrazide moieties and exhibit temperature responsiveness. Based on the forming and breaking of acylhydrazone between ketone and hydrazide group upon pH variation, the mixture of the two copolymers can undergo the sol-gel transition. In the formation of hydrogel, micelles will form in network by increasing the temperature, and the micelles will encapsulate the dynamic covalent bonds in microdomains, which will improve the mechanical properties of hydrogels. The process will be reversible by cooling. Combination the testing results of hydrogel’s performances and investigation of microstructure of hydrogels will reveal the responsive mechanism. And then the scientific correlation between polymer structure, triggers (pH and temperature), hydrogel’s structure, and gel’s properties including mechanical properties, stability, self-healing and sol-gel transition ability will be elucidated, providing the theory and scientific data for its potential application.