Biocompatible graphene/chitosan hybrid aerogel reinforced polydimethylsiloxane nanocomposite with excellent dielectric properties

A longstanding challenge in fabricating high-dielectric polymer composite is how to rationalize structure design to improve dielectric constant while minimizing dielectric loss. In this work, we provide a critical material design concept for high-performance flexible dielectric nanocomposite (PCGA) based on backfilling polydimethylsiloxane (PDMS) matrix into the pre-constructed chitosan-reduced graphene oxide (rGO) aerogel with 3D conductive network. Herein, the 3D conductive network enables PCGA to achieve the percolation threshold with a small amount of rGO, which improving the dielectric constant. Simultaneously, the chitosan insulating barrier layer prevents the generation of leakage current between conductive fillers interfaces, which suppressing the losses of the PCGA, thus ensuring the balance between dielectric constant and loss. The results demonstrated that the PCGA (0.06 g rGO) exhibited a dielectric constant as high as 297.3 and a loss tangent as low as 1.91. Subsequently, the as-obtained PCGA composites as a dielectric interlayer was employed for preparing capacitive sensor. The results demonstrated that the sensor possesses a desirable integration of high sensitivity (5.8% kPa(-1) in the pressure range 0-7 kPa) and wide work range (0-140 kPa) due to the synergistic effect of the excellent mechanical performance along with high-dielectric constant and suppressed loss.