Flexible sensors on polymide fabricated by femtosecond laser for integration in fiber reinforced polymers

Abstract

Polyimides have been known as a super-engineering plastic for more than 40 years due to their excellent thermal stability and mechanical properties. In recent years they have been recognized as key components for the fabrication of flexible sensing devices such as microsensors, microactuators, batteries and other micro-electro-mechanical systems. In this work, femtosecond laser micromachining of a polyimide (PI) film coated with Au/Cr films has been studied to understand the selective patterning mechanism of Au/Cr and ablation characteristics of the PI film. Once the proper process conditions for cutting of the PI film and removing of the Au/Cr coating without damaging the polymer substrate have been established, we were able to use the found process window to fabricate a very thin sensor on flexible polymer substrate that shows significant potential in using PI-based functional devices suitable for embedding in fiber reinforced polymer materials with minimal impairment of the load transmission path.