Conformal switchable superhydrophobic/hydrophilic surfaces for microscale flow control
The development of microvalves is essential to realize a fully integrated system for nano/microliter fluid handling in microfluidic devices. Microvalves that utilize passive fluidic manipulation employ a hydrophobic surface in a microchannel network in which the operation is controlled by the interfacial tension of the liquid-air-solid interface. In order to obtain a switchable valve in microfluidic channels, conformal hydrophobic/hydrophilic and superhydrophobic/hydrophilic thermal switchable surfaces were fabricated by the layer-by-layer deposition of poly(allylamine hydrochloride) (PAH) and silica nanoparticles followed by the functionalization of a thermosensitive polymer-poly(N-isopropylacrylamide) (PNIPAAm) and perfluorosilane. A fully integrated microfluidic valve using a thermal switchable superhydrophobic/hydrophilic polymer patch has been fabricated. At 70 degrees C, the valve is superhydrophobic and stops the water flow (closing status) while at room temperature, the patch becomes hydrophilic, and allows the flow (opening status). Published by Elsevier B.V.
Colloids and Surfaces a-Physicochemical and Engineering Aspects
"Conformal switchable superhydrophobic/hydrophilic surfaces for microscale flow control" (2009). Faculty Bibliography 2000s. 1428.