Microfluidic switches driven by mechanically guided multistable buckling

Reconfigurable microfluidic devices are of growing interest in microfluidic chemical analysis and separation system, since their channel network topology can be adjusted conveniently, in a dynamic and reversible manner. Such reconfigurability is important for a variety of engineering applications. Compared with the existing reconfiguration methods, mechanically-controlled reconfiguration approach is promising, because of the applicability to diverse materials, without potential negative effects to the electromagnetic devices during operation. In this work, we introduce a reconfiguration strategy that exploits multistable structure to control the flow in microchannels. Here, the configuration of a cross-shaped device is reversibly altered by the loading/releasing sequence of the elastomer platform beneath, thereby changing the open/close status of the channels inside the device. The cross-sectional geometry of the channel is systematically studied to reveal the underlying physics. Quantitative experimental and FEA results provide design guidelines of the microfluidic device. Through a bottom-up design strategy, a single reconfigurable switch device can be repeated to form a switch device array, capable of controlling multiple channels. A demonstration of a 3x1 switch array illustrates the utility of these ideas.