Flexible Loop Heat Pipe Driven by Micropillars for Wearable Devices

This work reports on a flexible thermal transport MEMS device driven by the capillary force of micropillars. In particular, it aims to enhance the device performance by improving liquid and gas sealing properties while introducing a quantitative method to evaluate thermal performance in bended positions. In the improved design, capillary force generated at micropillars are employed in the flexible evaporator as micropumps to drive the working fluid. The use of Parylene, paraxylene-based polymer, in the fabrication process improves sealing properties, enhancing overall device performance. A heat load test in the curved posture was performed, and heat transport performance of 3.0 W was demonstrated.