Micro-Dispensing of Graphene Oxide Based Capacitive Tactile Sensors for Human Pressure-Pulse Detection

This paper reports a novel capacitive pressure-pulse sensor array based on drop-dispensed graphene oxide (GO) sensing elements. The utilization of drop dispensing technology enables us a low cost, flexible and precise method to fabricate multiple capacitive sensing elements. The printed droplets volume (GO aqueous dispersion) were around 33.5 to 65.4 pL with droplet diameter ranging 40 to 50um. The size (i.e., footprint and dielectric thickness) of a sensing element can be controlled by the total GO dispersed. In this paper, we report on the fabrication process and preliminary characterization of these printed GO capacitive sensors. Thus far, we have shown that these sensors have a sensitivity of ~10−3kPa-1, with a relative permittivity of the printed GO being ~6 to 7 (measured at a frequency of 600kHz). We have also demonstrated that the printed sensing elements can be used for human pulse sensing, which means that these sensors could potentially be used in wearable electronics and healthcare applications.