中文摘要：

采用不同方法制备了聚乙烯醇（PVA）水凝胶，研究了制备参数对水凝胶／玻璃摩擦体系的影响．结果表明，混合溶剂有利于凝胶均匀网络的形成，制备的凝胶强度较高；冷冻解冻次数的增加有利于PVA水凝胶强度的提高；超高相对分子质量聚氧化乙烯（PEO）的加入，可使PVA形成更为致密、均匀的网络，显著提高PVA水凝胶的模量（E）．低滑动速率（v）时，高E的水凝胶具有较高的摩擦力（f），但易在较低”下形成流体动力润滑，使其在较高v（10^-1～10^0m／s）时反而呈现出较低的摩擦力，该速率范围与人体正常行走时膝关节软骨的运动速率相当．PEO的加入可降低较高v时的f，而低v区f的降低与加入的PEO浓度有关．

英文摘要：

Poly（vinyl alcohol） （PVA） hydrogels were prepared under different conditions such as the various concentrations,solvents, the times of freeze-thaw circles and the introduction of polyethylene oxide （PEO）. Effect of these preparation parameters on the frictional behavior of PVA hydrogels sliding on a glass surface was investigated in detail. The results show that mixed solvent of water and dimethyl sulfoxide facilitates the formation of a more uniform gel network and thus increases the strength of hydrogels. Moreover, the strength of hydrogels can also be increased by increasing freeze-thaw circle times and adding ultrahigh molecular weight PEO due to the formation of a dense and uniform network. On the other hand, stiff hydrogels with high modulus show a higher frictional stress at a low sliding velocity compared with soft hydrogels; however,it is fast to get into the hydrodynamic lubrication and exhibits a lower frictional stress at a high sliding velocity. The velocity （10^-1 -10^0m/s） is approximately the cartilage sliding velocity of the knee when people are walking. In addition,PEO molecular brush can reduce the frictional stress of PVA sliding against glass at high sliding velocities to some extent, however, at low sliding velocities, the reducing of frictional stress depends on the concentration of the added PEO. It suggests that increasing the modulus of hydrogels is more effective in reducing the friction at high sliding velocity region than that of introducing PEO with ultrahigh molecular weight.