Photothermally induced liquid gate with navigation control of the fluid transport

Abstract The ability to control multiphase flows is essential for applications such as microvalves, chemical analyses, microreactors, and multiphase separators. Furthermore, more specific controls, including the positional navigation control of fluids under steady-state pressures, will improve the development of these applications. Here, we present a fundamentally new photothermally induced liquid gating system that allows light-controlled contactless fluid transport and gas/liquid separations at designated locations, with seconds response times, under constant pressures. Experiments and theoretical calculations demonstrate the stability of our system and its novel regulation mechanism, which is based on a photothermally induced liquid-reconfigurable gate with a change in the surface/interfacial tension and Marangoni flow redistribution of the gating liquid at the illuminated location. This regulation mechanism with positional navigation properties requires neither mechanical parts nor complex accessories and can further enable the miniaturization and integration of various engineering processes. Our application demonstrations confirm the potential of this system in fields of smart valves, multiphase separations, multiphase microreactors, and beyond.