Tough Double-Network Gels and Elastomers from the Nonprestretched First Network

Double-network (DN) gels and elastomers, which consist of two (or more) rubbery polymer networks with contrasting physical properties, have received significant attention as they are extremely tough soft materials. The first network of tough DN materials should be more brittle and weaker than the second network. In this paper, we re-examined the structural requirements of the covalently cross-linked first network of tough DN materials and...