Fabrication Of Graphene-Reinforced Liquid Gating Membrane For The Gas/Water Separation Application

The liquid gating system combines the advantages of tunable multiphase selectivity and excellent antifouling behavior.It is significant to develop responsive liquid gating system by the design of membrane materials and gating liquids.This thesis focuses on the design and optimization of membrane materials,the fabrication of stable liquid gating elastomeric porous membrane system and the study of dynamic gas/water transportation and separation under a steady-state applied pressure.The main contents are as follows:(1)The rGO/PDMS composite membranes are prepared by mechanical mixing and solution mixing method.Due to the lack of interfacial bonding in the rGO/PDMS composite,its mechanical properties need to be improved by functional modification.(2)The GO/TPU composite membranes are successfully prepared by solution mixing method.The effect of GO fillers on the mechanical performances of the composites is studied.The GO/TPU composite with 1 wt.%of GO exhibits 6182.09%strain and the tension strength is 60.90 MPa,which greatly improves the durability of the membrane.Porous GO/TPU membrane is fabricated by laser cutting method,showing homogeneous distribution of pore sizes.(3)The GO/TPU composite with 1 wt.%of GO is chosen as the candidate for multiphase separation to obtain stable GO/TPU composite liquid gating membrane system,the interfacial energies,wettability,the interfacial energy between the solid and liquid and the critical pressure of gas and liquid under steady-state applied flow rate are studied.For GO/TPU porous membranes with 1 wt.%GO,taking silicone oil as the liquid gating and DI water as the transport liquid,the system is stable and exhibits excellent gas/water separation performance and antifouling behavior.(4)The critical pressure of gas and water transporting through the GO/TPU composite liquid gating membrane system at different flow rates are further studied.From the stability of system and gas/water separation performance,the flow rate at 500μL/min is chosen for further experiments.Compared with the bare membrane,this liquid gating system could obtain 32.7%energy saving efficiency.The gating pressureis related to the pore size.The pressure decreases with increasing pore size.Therefore,by simply adjusting the mechanical stress on the liquid gating system under a steady-state applied pressure,the critical pressure of the gas and liquid can be dynamically tuned,the gas/water separation efficiency is up to 97%.Stress responsive GO/TPU liquid gating system provides a new strategy for gas/water separation,multiphase separationand multiphase microreactions.