Laser-Patterned Polyurethane Composites with Graphene, Graphene Oxide, and Aramid Fibers for the Production of Electric Circuits, Sensors, and Heaters

The patterning of composites with carbon-based additives of nanometer or micrometer size was studied by the precise modification of material surfaces using laser technology. Initially, the composites are electrical insulators, but we can make them conductive by selective patterning; this process allows us to create conductive tracks within seconds, with a sheet resistance that can be adjusted over a wide range, from 108 Ω/sq down to 2.5 Ω/sq. The additives used include graphene nanoplatelets, graphene oxide nanosheets, and aramid fibers. By conducting microscopic and spectroscopic characterizations before and after laser treatment, we can distinguish between two different processes that lead to electrical conduction: (a) localized increase in the concentration of conductive additives or (b) localized reduction and pyrolysis of insulating additives. To demonstrate the versatility and usefulness of this technique in different fields of application, such as automotive, we fabricate three different devices on polyurethane: a heater, a proximity sensor, and an amperometric sensor for detecting biological analytes.