Graphite nanoplatelet thin film enabled piezoresistive sensors - From fabrication, evaluation to applications

Graphite nanoplatelet (GNP) thin film enabled piezoresistive sensors were developed, characterized and demonstrated for use in structural health monitoring (SHM) and man-machine interaction. By using a scalable process - spray coating of aqueous GNP dispersion on flexible PET, 1D single glass fiber, and highly stretchable nitrile glove, GNP thin film enabled PET sensors (GNP/PET), GNP thin film enabled fiber sensors (GNP-FibSen), and GNP thin film enabled finger sensors (GNP-FinSen) were respectively fabricated for different purposes. First, the microstructures and piezoresistive behaviors of GNP thin films have been systematically studied using GNP/PET sensors. Depending on the thickness of GNP thin films, high gauge sensitivity (>20) can be achieved. Then, for SHM purpose, the GNP-FibSen sensor can be readily and non-invasively embedded into polymeric composite structures at desired location for multiple applications. This includes the in-situ monitoring of resin curing for quality assurance of the host composite structure and mapping the strain and stress to diagnose its health state. Moreover, be attributed to the largely and reversibly extensibility of GNP thin films, the GNP-FinSen could be used as wearable sensors on human body. This unique behavior along with their high gauge sensitivity warrants the GNP-FinSen sensor to capture different finger motions, which is highly promising for applications in man-machine interaction and motion capturing.