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,N'-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 IR-responsive nanocomposite hydrogel, we have also realised a microvalve that controls the fluidic flow within a microfluidic channel through remote IR light actuation.