Nano-bubble Valve

Valve technology is one of the important elements in micro or nanofluidic control. Many valve technologies have been realized for microfluidic control, by which the applications of microfluidic devices have expanded. However, valve technology for nanofluidic control (nanovalves) is still challenging due to the ultrasmall size (100 nm scale) of the nanochannels. We propose a novel nanovalve that utilizes nanobubbles. The entire nanochannel surface is made hydrophobic by surface modification. Nanobubbles are generated by light and removed in the nanochannels. The basic principle of nanobubble generation and removal was confirmed, and the valve function was confirmed by the introduction/cessation of pure water, which led to a change in the concentration of a fluorescent solution after mixing with the pure water. As a result, the high performance (70 ms response time and 400 kPa pressure capacity) of this simple nanovalve was demonstrated.