水溶性线性高分子与原位聚合的高分子链间可形成很强的协同氢键作用，进一步交联形成具有良好力学性能的水凝胶。本工作选用聚乙烯醇为高分子链，丙烯酸为小分子单体，通过热引发原位聚合得到了基于协同氢键作用的高弹性PVA-in situ-PAA水凝胶。研究了PVA和AA的配比对水凝胶力学强度、回弹性能及流变性质的影响。PVA的加入能够提升凝胶的力学性能和回弹性能。凝胶的断裂应力和杨氏模量随PVA量的增加而上升，断裂应变随PVA量增加表现出先增加后减小的趋势，CPVA/CAA为10%时凝胶的断裂应变达到最大值1600%。此外，这些凝胶还具有优良的回弹性能，应变较高（700%）时，加入PVA复合的凝胶回弹率依然能够达到70%以上。流变测试表明凝胶在较宽的温度范围内仍能维持良好的弹性。PVA-in situ-PAA水凝胶具有优良的水驱动形状记忆能力，干燥的凝胶螺旋在25℃水浴中仅需25 min即可回复为初始形状，而在60℃水浴中凝胶的回复速度较室温提高了2.75倍，完成形状回复仅需8 min。其形状回复速率比已报道结果要快得多。

Strong cooperative hydrogen bonding can be formed between some water-soluble linear polymersand in situ-polymerized polymer chains, leading to the formation of hydrogels with good mechanical properties in some cases. Here we report a kind of highly-elastic hydrogels crosslinked by cooperative hydrogen bonding between polyvinyl alcohol (PVA) and in situ-polymerized polyacrylic acid (PAA) chains. The feeding ratio (CPVA/CAA) influences the hydrogels’ mechanical strengths, resilience and rheological properties. Adding a small amount of PVA could largely enhance the tensile strength, Young’s modulus and resilience of the hydrogels, while the elongation increases first and then decreases. At a CPVA/CAA ratio of 1/10, the elongation reaches a maximum of 1600%. These PVA-in situ-PAA hydrogels also have excellent resilience, as indicated by the high resilience ratios of more than 70% even at a high strain of about 700%. Rheology study shows that the PVA-in situ-PAA hydrogels maintain very stable elasticity in a wide temperature range. In addition, these hydrogels show very interesting water-triggered shape memory behavior. Dried hydrogel helices could recover to their original shape within only 22 min when they are immersed in 25?C water, and the shape recovery takes only 8 min in 60?C water, i.e. 2.75 times that in 25?C water. The shape recovery rates of our hydrogels are much faster than those ever reported.