Development of a selectively liquid-blocking and vapor-passage microfilter based on polyurethane-aerogel microfibers

In this study, we developed a liquid–vapor selective microfilter woven into a mesh using polyurethane (PU)–aerogel microfibers. The aerogel particles embedded on the surface of a PU microfiber provided liquid repellent properties, and the liquid–vapor selective microfilter allowed only vaporized chemical substances to pass through, while blocking liquid chemicals and water. An SnO2 nanowire transistor covered with the liquid–vapor selective microfilter was used as a chemical sensor to detect the concentration of chemical substances, such as nitric acid, benzene, and toluene, in water. The time-dependence response of the sensor depending on the type of chemical present in water showed reproducible response and recovery properties for multiple cycles.