Microstructured flexible capacitive sensor with high sensitivity based on carbon fiber-filled conductive silicon rubber

Flexible sensors with high sensitivity and stability have been tremendously attractive in recent years. In this study, flexible capacitive sensors (FCSs) with microstructured-surface were fabricated, where electrode layers (e-layers) and dielectric layers (d-layers) of the FCSs were sprayed with carbon fiber (CF) filled-polydimethylsiloxane (PDMS) and pure PDMS on substrate with surface roughness, respectively. Sensitivity of the fabricated FCSs to compressive load was evaluated. Influence of the surface microstructure of Dand e-layers on the sensitivity was studied through in-situ microscopic observations and theoretical capacitance calculations. Results showed that the roughness of the surface microstructure did have a correlation with the sensitivity. Excellent sensing performance, including a high sensitivity (similar to 0.82 kPa(-1)), ultrafast response (similar to 0.2 s) and relaxation (similar to 0.3 s) time, ultralow detection limit (similar to 1.2 Pa), and excellent stability (10(4) loading/unloading cycles) over a wide pressure range (0-50 kPa) appeared on the FCS with its surface microstructure size of 48.6 mu m in roughness. The high sensitivity of the fabricated FCS was dominantly resulted from the closing of air gap between eand D-layers. A 3 x 3 FCS array capable of distinguishing space pressure distribution and a mouse glove capable of inputting computer information were finally fabricated which demonstrated a prospect of the FCS in micro-load response and human-machine interaction applications. (c) 2020 Elsevier B.V. All rights reserved.