PEDOT:PSS Microchannel-Based Highly Sensitive Stretchable Strain Sensor

Abstract

This paper presents poly(3,4-ethylenedioxythiophene) polystyrene sulfonate polymer microchannel (diameter ≈175 µm) based stretchable strain sensor developed inside polydimethylsiloxane substrate. The microchannel diameter changes when subjected to various strains, leading to change in the resistance of strain sensor. The sensor exhibits about three order (ΔR/R0 ≈ 1200) increase in the resistance (R) for 10% applied strain (ΔL/L, L = length of the sensor). This leads to a gauge factor (GF Δ (ΔR/R0)/(ΔL/L) of ≈12 000, which is about ≈400 times higher than most of the reported polymer-based strain sensors. The sensor is evaluated up to a maximum strain of 30%, which is the standard strain limit associated with human body parts such as fingers and wrists. The sensor exhibits a considerably good average degree of hysteresis (<9%). Further, the sensor is also studied for bending and twisting experiments. A response of (ΔR/R0 ≈ 250) and (ΔR/R0 ≈ 300) is recorded for 90° bending and 150° twisting, respectively. The sensor shows an electrical resolution of ≈150% per degree of free bending and ≈12k% per percentage of stretching. Finally, the potential application of presented sensor in robotics and wearable systems is demonstrated by using sensor feedback from human hand to remotely control the robotic hand movements.