Thermoresponsive Graphene Membranes with Reversible Gating Regularity for Smart Fluid Control

Precisely regulating water and molecule permeation through membranes is of crucial significance in broad domains such as water filtration and smart reactors. Comparing with routine stiff membranes, stimuli-response polymers endow porous membranes with various gating properties, but most of these membranes have only one-way gating performance, that is, either positive or negative. Here poly(N-isopropylacrylamide) (PNIPAM) grafted graphene oxide (GO) membranes with reversible positive/negative gating regularity are constructed by simply tuning the molecule grafting density. The water and small molecule permeance of the membranes can be regulated by adjusting environment temperature. Based on this tunable thermoresponsive gating regularity, a bidirectional fluidic controlling system is designed by integrating a positive membrane and a negative membrane, which can be employed as a self-adaptive gating reactor. This strategy provides an insight into constructing smart gating membranes with extraordinary properties, showing promising applications in micro/nanofluidic valves and temperature sensitive biochemical reactors.