Ultralight Weight Piezoresistive Spongy Graphene Sensors for Human Gait Monitoring Applications

This work reports a facile method of fabricating ultralight weight (density of 0.305 g/cm3) and squeezable microporous graphene-PDMS piezoresistive sensors for human gait monitoring applications. The sensor reported in this work demonstrates piezoresistivity by utilizing the conductive domain discontinuity mechanism demonstrated by multilayer graphene nanoflakes populating the inner pore walls of microporous PDMS sponges. Quasi-static compressive strain characterization experiments conducted on the sensor revealed a linear response with a gauge factor of 8.77 for compressive strains up to 9.5%. Two identical graphene-PDMS sponge sensors embedded into a pair of soft shoe-soles were used to demonstrate comprehensive real-time gait monitoring, which includes pressure profiling of the heels of both the legs.