A highly stretchable and thermally conductive capacitive strain sensor based on rGO-PDMS composite for motion monitoring: A paradigm shifts towards sustainable electronics

Stretchable high-performance strain sensors with synergistic thermal regulation functions have attracted considerable interest in health monitoring and wearable electronics. However, accurate and reliable sensing efficiency under different mechanical stimuli with heat management is challenging. A synergistic interaction between the IrGO/PDMS composite dielectric layer and the AgNWs-silver paste conducting electrode has been discussed in detail. A mechanically robust, high sensitivity, response time, linearity, and low detection limit have developed a capacitive-type strain sensor. The sensing device was fabricated using a layer-by-layer assembly technique with a gauge factor of ∼9.7 at a 5.62 % sensing range and 0.08 % detection limit. The dielectric property and thermal conductivity of composite films were investigated to assess the film's capacitive behavior and heat transport phenomenon, respectively. The significantly enhanced properties, as mentioned earlier, were attributed to the homogeneous dispersion and orientation of the IrGO sheets that ultimately improved the dielectric constant by ∼635 % and thermal conductivity by ∼558 %. The sensing performance of the device was evaluated under different strains with ∼8.7 % hysteresis and long cyclic stability for >4500 cycles. These encouraging outcomes provide an innovative and feasible approach to designing multifunctionally capacitive strain sensors in personal healthcare and thermal regulation applications.