Hybrid spray-coating, laser-scribing and ink-dispensing of graphene sensors/arrays with tunable piezoresistivity for in situ monitoring of composites

Graphene based nanotechnology has offered a variety of novel strategies for enabling self-sensing and diagnosing functionalities for next-generation composites. In comparison to traditional methods with complicated procedure and limited scalability, a new process is impending for graphene sensor fabrication with designable shape and controllable performance. Toward this goal, this paper combined multiple computer-aided processes for designing graphene thin film sensors and arrays on composites, including spray-coating, laser-scribing and ink-dispensing. The processing-structure-property relationship was systematically investigated for understanding the piezoresistive performance of the laser scribed graphene (LSG) sensors. It is determined that by increasing the cycle time of laser irradiation, the gauge factor could be tailored up to 3 orders of magnitude from ∼450 to ∼0.6. The accumulated bump-shaped structure originated from intenser reduction of graphene oxide (GO) is believed to disrupt the efficiency of load-transfer and degrade the resulting performance. With the optimized recipe, versatility of LSG sensors and arrays deployed with ink-printed circuits was further explored for monitoring and mapping large-scale deformation and strain distribution of polymeric composites.