Design of Porous Membranes by Liquid Gating Technology

ConspectusPorous membranes are playing paramount roles in the areas of wastewater treatment, chemical analysis, energy storage and conversion, flexible devices, and biomedical engineering. Despite their significance in the above fields, the performances of the porous membrane will be weakened due to the inevitable membrane fouling. Solid surfaces or pores of the membranes are easily contaminated or even clogged due to the absorption of small molecules or the accumulation of fine particles, which lower the flux of fluid transport over time, reduce the separation efficiency, shorten the lifetime of the membranes, and increase the operational costs. In addition, the defects in membranes also hinder their applications to some extent. The above-mentioned limitations all arise from the intrinsic properties of the solid surfaces of the membranes. To solve these challenges, liquid gating technology was proposed, which utilizes the capillary-stabilized functional liquid as a pressure-driven, reversible, and reconfigurable gate to fill and seal the pores on demand. Using liquid gating technology, multiphase transportation in the membrane can be modulated with exceptional antifouling and energy-saving manners due to the defect-free molecular-smooth liquid interface. Moreover, the further responsive interface design accelerated the development of liquid gating membranes and their practical applications to a great extent. In recent years, the concept of the liquid gating membrane has become a reality through developing various porous membranes by the rational selection and design of the two essential parts of the composite membranes: the solid porous matrix and the gating liquid. These membranes expand the basic scientific issues of the traditional membranes from the solid–liquid/gas interface to the solid–liquid–liquid/gas interface and bring more possibilities for the applications of porous membranes. With properties and advantages of antifouling, anticorrosion, enhanced transparency, energy-saving, and stability, these porous membranes have shown various applications in multiphase separation, biomedical catheters, chemical detection, mobile valves, microscale flow control, etc.In this Account, we provide a systematic review of our group's recent progresses in the design and applications of porous membranes with liquid gating technology. First, we give a comprehensive introduction to the liquid gating technology, followed by further details on how to design porous membranes through liquid gating technology and properties and advantages of the porous membranes. Second, we discuss the applications of these porous membranes in the fields of multiphase separation, biomedical catheters, chemical detection, mobile valves, and microscale flow control. Third, we conclude the Account by describing the current challenges and future directions of the field.