Temperature-responsive Poly-N-isopropylacrylamide (PNIPAAm) hydrogels were modified with graphene oxide (GO) nanoparticles to increase the light absorption significantly and these gels can be heated and stimulated optothermically. These light-responsive hydrogels are promising candidates as actuator material for microfluidic applications. For demonstration, the hydrogels were tested as light-driven valves for the active flow control within microfluidic channels by monitoring the pressure and flow for different operation states.
