Processing improvement of response and stability of strain sensor based on CNT‐bioplastic composite for estimation of elbow angles

Abstract

AbstractBioplastic is an emerging candidate for replacing traditional fossil‐based plastics due to its fewer carbon emissions, ease of recycling, and high degradability. Current research has shown that bioplastics benefit many applications, such as packaging, kitchenware, drug delivery, and sensors. However, high electrical resistance and poor stability of bioplastic are barriers to electronic components in robotic, bionic, and exoskeleton applications. Here, we introduce a novel bioplastic application as a strain sensor to estimate elbow angles for controlling exoskeletons. This study utilized extracted agar from red algae as the matrix, incorporating various concentrations of carbon nanotube (CNT) as a filler. The results were remarkable, with the increase in filler concentration not only improving strain from 0.8 to 1.1 but also stress from 35.2 to 45.8 kPa, surpassing commercial plastic by approximately two times. The optimized sensors have a response time of 0.16 s, a recovery time of 0.25 s, and stability over 10,000 cycles. Furthermore, the CNT‐bioplastic sensor is seamlessly integrated with the exoskeleton. Our work is a significant step toward using bioplastic in electronic applications.