本项目针对广泛存在的氢键缔合型物理水凝胶中尚未解决的宏观流变行为的分子机理开展研究工作，为了构建宏观性质和微观分子的联系，我们拟通过实验和模拟相结合，以纳米硅粒子接枝聚合丙烯酰胺(PAM)水凝胶作为模型体系，多尺度研究以氢键为主要物理交联点的水凝胶的物理凝胶化机理及其流变行为。一方面通过实验获得温度、浓度、pH值等对物理凝胶的微观和介观结构及其流变性质的影响规律；另一方面建立微观模拟方法，探讨静态和剪切下氢键成键方式与分子链松弛行为和氢键缔合解离之间的关系；并进一步建立跨尺度模拟方法，将以上微观化学结构信息提取至粗粒化模型，介观尺度获得瞬时结构及其演变规律，明晰氢键协同作用形成机制。通过实验和模拟比较，验证模拟模型；进而揭示不同相互作用耦合导致成键方式差异的根源，阐明介观聚集结构与氢键成键方式之间的关系，提出氢键协同作用的调控机制，最终揭示宏观流变性质的分子机理和物理本质。

Using experimental and simulation techniques, we propose to study the physical gelation behavior and mechanical properties of Si-graft-Polyacrylamide(Si-g-PAM) nanocomposite in water. Experimentally we aim to investigate the rheological properties of the system under the influence of conditions such as temperature, concentration, grafting density and shear. In combination with simulation work, we focus on revealing the relationships of hydrogen-bonding formation with molecular motion and relaxation of physical crosslinks. We pass the chemical details of microscale modeling to implicit mesoscale modeling, i.e., we establish a multiscale simulation method to study the formation of cooperative hydrogen-bonding structures. We testify the multiscale modeling by comparison with corresponding experiments. Therefore, we are able to investigate the gelation structure in much larger length and time scales without losing chemical identity. By combination of simulation and experiments, we disclose the influence of coupling among different interactions on the formation of hydrogen-bonding structures, and elucidate the relationships between hydrogen-bonding dynamics and formation of mesoscale strucutures. In total, we expect to build a multicale study method of hydrogels formed through physical interactions such as hydrogen-bonding, which help to uncover the mechanisms of physical gelation and mechanical behavior.