New Approaches to the Design of Double Polymer Networks: a Review

The review addresses modern approaches to the synthesis of mechanically tough polymer hydrogels which are based on the concept of double networks. Various types of double networks, such as covalently crosslinked networks; hybrid networks, in which one network is crosslinked by covalent bonds and another network is crosslinked by labile dynamic bonds; and networks that are constructed using labile bonds in each network, are considered. Double networks consisting of one polymer network and one supramolecular network, nanocomposite double networks, and multicomponent (three-component, four-component, etc.) networks are described. Advantages and disadvantages of new approaches to designing mechanically tough double networks are considered.