Hybrid double-network hydrogels with excellent mechanical properties

Abstract

This work presents a hybrid double-network (DN) polymer–clay hydrogel with superior mechanical properties. The hybrid hydrogel is composed of covalently cross-linked poly((3-acrylamidopropyl)trimethylammonium chloride) (pATC) as the first network and poly(acrylamide-co-2-acrylamido-2-methylpropanesulfonic acid) (p(AAm-AMPS)) as the second network in the presence of montmorillonite. MMT platelets are considered as chemical “plane” cross-linkers different from “point” cross-linkers because of the cation-exchange reaction between MMT and ATC (the cationic monomer) during the synthesis of the hydrogels. The results of scanning electron microscopy revealed that large quantities of micro-network structures were located in the pores and the formation of embedded micro-network structures. The DN and the electrostatic interactions between ATC in the first network and AMPS in the second network improve the mechanical properties of the hydrogels. Our facile approach establishes new opportunities in the design and fabrication of high performance hydrogels for a wide range of applications.