Nanocomposite hydrogels

Hydrogels, which consist of three-dimensional polymer networks and large amounts of water, have long been believed to be interesting but mechanically fragile materials limited to specific uses. Recently, important breakthroughs have been made as a result of the creation of nanocomposite hydrogels (NC gels), and most of the traditional limitations of hydrogels have been overcome. NC gels are prepared by in situ free-radical polymerization at high yield under mild conditions (near ambient temperature, without stirring), and various shapes and surface forms are readily obtained. Because of their unique organic (polymer)/ inorganic (clay) network structure, high toughness and excellent optical properties and stimulus-sensitivity are simultaneously realized in NC gels. Furthermore, NC gels exhibit a number of interesting new characteristics. In this paper, the fundamental and recent developments related to NC gels are reviewed. (C) 2008 Elsevier Ltd. All rights reserved.