Self-optimizing, thermally adaptive microfluidic flow structures

Although microfluidic devices offer many benefits, high fluid shear stresses in such devices are an undesirable consequence of miniaturization. In the present study, we present an adaptive "smart" design that mitigates the effects of high shear stresses in microfluidic-based devices by autonomously optimizing its internal flow structure. This concept was demonstrated by testing a prototype microscale thermal-fluid device that responded to changes in the local thermal environment. The autonomous, self-optimizing functionality was achieved using poly(N-isopropylacrylamide) hydrogel actuated microvalves, which independently controlled the flow to four distinct regions within the device. The experimental results showed that the device optimized its internal topological flow arrangement such that fluid was delivered only to regions where cooling was required. As a result, a series of spatially distributed thermal loads were dissipated with minimal pumping power consumption.