不同体系的双网络水凝胶及其增强机理

Different Systems of Double-network Gels and Their Reinforcing Mechanisms

双网络水凝胶是由两种不同性质的聚合物形成的互穿网络,第一层为紧密交联的刚而脆聚电解质网络,第二层为松散交联的软而韧中性网络。双网络水凝胶具有极高的机械强度和韧性,甚至可以与橡胶相媲美。其中,刚而脆聚电解质网络为双网络水凝胶提供了"牺牲键",起到分散外界应力的作用;而软而韧的中性聚合物填补于刚性网络中,为双网络水凝胶提供了支架,保持水凝胶外形。基于上述机理,研究者设计合成了具有高强度、良好生物相容性、低摩擦和低磨损等特性的双网络水凝胶。着重讨论了不同体系双网络水凝胶的力学性能和增强机理,并展望了双网络水凝胶研究前景。

The double-network gels possess interpenetrating network structure,which is made up of two different kinds of polymers.The first network composed of rigid and brittle polyelectrolytes is tightly cross-linked,while the second network composed of soft and ductile neutral polymers is loosely cross-linked.The double-network gels manifest excellent mechanical properties as well as super high toughness comparable to rubbers.The rigid and brittle network constituted by polyelectrolytes serves as＂sacrificial bonds＂,which disperse the external stress;meanwhile,this rigid network is filled with soft and ductile polymers which provide support for the double-network gel to maintain its shape.Based on the mechanism described above,some double-network gels exhibiting high strength,good biocompatibility,low friction resistance and low wear characteristics have been designed and fabricated.The mechanical properties and the reinforcing mechanisms of various double-network gels are introduced.Moreover,the research prospects of double-network gels are discussed.