An interpenetrating glass-thermosensitive hydrogel construct: Gated flow control and thermofluidic oscillations

A simple means for weaving a hydrogel into a microdevice is presented. A glass plate is scored on both sides with trenches of depth slightly more than half the plate thickness. Trenches on the two faces of the wafer are perpendicular to each other, and integral holes are formed at the intersections between the perpendicular trenches. This crosscut microstructure is readily loaded with a hydrogel, which interlocks with the wafer. When the hydrogel is thermoresponsive in its swelling, the hydrogel crosscut construct (HyC) can be used for thermofluidic gating of flow perpendicular to the plate surface. A simple test rig to demonstrate this principle is constructed, and response times to changes in temperature are determined. An autonomous thermofluidic oscillator, which makes use of the HyC and functions by the coupled dissipation of thermal and hydraulic pressure gradients, is demonstrated.