近年来，高强度水凝胶取得了很多重要进展，多种动态键被广泛嵌入到聚合物水凝胶网络中用于增强水凝胶的力学性能，自恢复(self-recovery)性能，并赋予水凝胶一定程度的刺激响应性。从微观层面上，水凝胶网络具有多尺度的结构不均匀性，然而定量表征这种多尺度结构不均匀性对水凝胶宏观性能的影响却鲜有报道。因此，本项目拟在制备高强度水凝胶的基础上，主要利用多种先进的固体NMR技术，结合宏观力学性能测试，流变学等方法，在分子水平上定量表征交联聚合物水凝胶的化学组成，在1nm~100nm的空间尺度上对聚合物水凝胶网络结构不均匀性（包括交联网络网格尺寸，交联点不均匀分布，网络缺陷类型及含量等）进行深入研究，并进一步阐明聚合物微观链段动态松弛行为对水凝胶黏弹性的影响，为聚合物交联网络理论的发展提供实验依据。在此基础上，将进一步发展原位表征水凝胶动态键及链间/链内微观弱相互作用的固体NMR新方法.

In recent decades, significant progress has been achieved in the area of high-performance hydrogels. A variety of dynamic bonds have been widely incorporated into polymer network for enhancing the mechanical performance, self-recovery properties, and endowing the material with stimuli-responsive behaviors. However, on the microscopic level, there are multi-scale structural complexity and heterogeneity in polymer network, while there are rare quantitative studies on the influence of hierarchical structural heterogeneity on macroscopic properties. Herein, this project is aimed to systematically investigate the effect of structural heterogeneity on the macroscopic mechanical properties of hydrogels. Multiple advanced solid-state NMR methods, in combination with tensile test, rheology, will be utilized to quantitatively in-situ determine the chemical compositions of cross-linked hydrogels at the molecular level and investigate the structural complexity in detail on a length scale of 1nm~100nm, including the mesh size of network, heterogeneous distribution of cross-linkages, network defects, and so on. Moreover, we would like to elucidate the dynamic segmental relaxation behaviors of polymers in the dynamic cross-linked network as well as its influence on the viscoelastic properties of hydrogels, which can provide experimental guidance for the development of associative polymer network theories. On that basis, we would like to further develop novel solid-state NMR methods for in-situ probing the dynamic bonds and intra-/inter-segmental weak interactions in polymer hydrogels.