Bioinspired Stretchable Strain Sensor with High Linearity and Superhydrophobicity for Underwater Applications

Abstract

Flexible strain sensors are of great significance in health monitoring, wearable electronic devices, intelligent robot sensing, and other fields. Most of the reported works focus on the enhancement of sensitivity or working range, while linearity is ignored and exhibits strong nonlinearity. Conflict among performances remains a serious challenge for the development of flexible strain sensors. Herein, inspired by the architecture of butterfly's wings, a strain sensor with double conductive layers and wrinkles/holes structures is proposed. The fabricated sensor shows a high linearity of >0.98 over a full working strain range of 120%, and a linearity of up to 0.999 within a strain range of 0%–30%. Apart from that, the sensor also presents a sensitivity of 8.28, high stability over 40 000 cycles when subjected to a full-scale strain, as well as a water contact angle of >167.4°. Meanwhile, strains as low as 0.075% can be identified, while a maximum frequency of 40 Hz can be responded to for the sensor. It is demonstrated that the sensor is capable of enabling flexible grippers to sense and monitor the motions of underwater vehicles, indicating its greater potential for diverse applications, such as human–machine interaction, marine environmental protection, and biological research.