Flexible Capacitive Tactile Sensors Based on GO/CNF/PDMS Aerogel

Porous structures such as the dielectric layer have been identified as an effective way to enhance the performance of capacitive tactile sensors and aerogels as three-dimensional structured materials with high porosity and excellent mechanical properties, which have been shown to have the potential to further improve the overall performance of capacitive sensors. However, the inherent low compressive modulus of elastic aerogels limits their functionality, especially when subjected to larger pressure ranges, posing a challenge for extending the working pressure range of aerogel-based sensors. In this work, we combined graphene oxide (GO) with cellulose nanofibers (CNF) and polydimethylsiloxane (PDMS) to form a composite aerogel as the dielectric layer in a capacitive tactile sensor, aiming to overcome the inherent shortcomings associated with conventional aerogels. The results demonstrated that the composite aerogels preserved high porosity and exhibited superior elastic properties to significantly enhance the overall performance of the tactile sensor. The sensor exhibits a sensitivity of up to 1.7 kPa-1, within a working range of 80 kPa, together with a rapid response time of 46 ms and a relaxation time of 92 ms. Additionally, the sensor featured an ultra-low detection limit of 30 Pa and maintained excellent stability under continuous load cycles. The performance and the flexibility of the sensor fit well for tactile perception and wearable detection applications.