An infrared-light responsive graphene-oxide incorporated poly(N-isopropylacrylamide) hydrogel nanocomposite

We demonstrate a new light-responsive poly(N-isopropylacrylamide) (PNIPAAm) hydrogel nanocomposite incorporating glycidyl methacrylate functionalized graphene oxide (GO–GMA) instead of metallic nanoparticle fillers. GO–GMA is synthesized by esterification with glycidyl methacrylate. GO–GMA incorporated hydrogels are synthesized by photopolymerization of NIPAAm including 4-dimethylaminopyridine (DMAP) and N,N0-methylenebisacrylamide (NMBA) in GO– GMA dispersed dimethyl sulfoxide (DMSO) solution. Results show that such a nanocomposite hydrogel can undergo a large volumetric change in response to infrared (IR) light illumination, due to the highly efficient photothermal conversion of GO–GMA. It also exhibits significantly larger water uptake compared to conventional PNIPAAm hydrogel by 3 times. Based on the developed IRresponsive nanocomposite hydrogel, we have also realised a microvalve that controls the fluidic flow within a microfluidic channel through remote IR light actuation.