A transparent Laponite polymer nanocomposite hydrogel synthesis via in-situ copolymerization of two ionic monomers

The poor stability of clay dispersion in the presence of ionic species presents a challenge for preparing ionic clay polymer nanocomposite (CPN) transparent hydrogel with desired strength. The transparent and tough ionic hydrogels are highly demanded as potential material options for contact lens or ophthalmic implants. Here we reported an ionic CPN hydrogel with combined high transparency and mechanical properties synthesized via in-situ copolymerization of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and acrylic acid (AA) in Laponite dispersion. The ionic transparent CPN can have strength of 189 kPa and a strain of 1780% which is likely a result of uniformly dispersed Laponite platelets in the structure. A synergistic interaction between acylamino and sulfonic acid functional groups was found to play a key role in the stable dispersion of Laponite. This work provided a new way to prepare transparent ionic CPN hydrogels.