Fig. 3: Effect of material on response-relaxation time.

a Storage modulus (E’), loss modulus (E”) and their ratios of pure PDMS (with elastomer and curing agent ratio of 5:1), PDMS-CNTs composite (with 2 wt.% CNTs and 7 wt.% CNTs). b Adhesion force of pure PDMS (with elastomer and curing agent ratio of 15:1 and 5:1), PDMS-CNTs composite (with 2 wt.% CNTs and 7 wt.% CNTs). c The adhesion strength of 2 wt.% PDMS-CNTs with three different interfaces. d Response time of six sensors: sensors with non-boned interfaces consisting of three different dielectric layers made of pure PDMS (with elastomer to curing agent ratios of 15:1 and 5:1) and PDMS-CNTs composite and sensors with a bonded interface based on three different dielectric layers of pure PDMS (with elastomer to curing agent ratios of 15:1 and 5:1) and PDMS-CNTs composite. Error bars represent the standard deviation of three repeated measurements of the time. e Relaxation time of the six sensors mentioned in (d). f Dynamic response of the sensor as a function of time under a pressure of 100 kPa. g Normalized change in capacitance of the sensor during the loading and unloading cycle at a pressure of 100 kPa. h Response of the pressure sensor to cyclic rubbing (10,000 cycles) under a combination of pressure (200 kPa) and a shear (45 kPa). The friction test was performed by applying a sheet of #1000 sandpaper to the surface of the sensor.