Low‐Cost and High‐Speed Fabrication of Camouflage‐Enabling Microfluidic Devices using Ultrahigh Molecular Weight Polyethylene

This study demonstrates a multi‐spectrum camouflage control via microfluidic methods within a thermally and visibly semi‐transparent polymer (polyethylene). Microfluidic devices have a high potential for achieving multiband camouflage including both visible and infrared (IR) spectrums because they can manipulate fluids that may be dyed, transparent, or opaque to different parts of the electromagnetic spectrum. However, most traditional polymers used for microfluidics are not very transparent in the thermal IR region (≈8–14 um wavelengths), which limits their effectiveness in this spectrum. It develops a high‐speed, low‐cost robust process to fabricate microfluidic devices entirely made from polyethylene using xurography and thermocompression molding techniques. Moreover, a novel method that thermally bond macro‐scale polyethylene tubing to micro‐scale channels is developed. The simplicity and flexibility of the method allow the fabrication of devices with different channel heights, widths, and patterns. Upon filling the microfluidic devices with dyed liquids and testing them with different backgrounds, the devices show fast and high visible camouflage capabilities. Moreover, the thermal IR appearance of microfluidic systems can be altered without changing temperature by incorporating a metalized surface which can be covered by an IR opaque liquid to alter the apparent temperature when reflecting IR sources.