Durable and highly signal-stable pressure sensors prepared by sequential thiol-acrylate click reactions

Abstract

Pressure sensors are an important part of the Internet of Things (IoT) and human–machine interaction (HMI), and their signal stability and durability are greatly affected by the interfacial interaction between the substrate and the conductive layer. Herein, a pressure sensor prepared by sequential radical-mediated thiol-acrylate click reactions is reported. In first click reaction, the porous substrate polyHIPE-SH with inherently thiols is fabricated. Those thiols give us second chance to chemically bridge carboxylic carbon nanotubes (CNT)/polyethylene glycol diacrylate (PEGDA) conductive coating to the substrate using the click reaction, with 21.5 % of the thiols on the substrate involved in the reaction. As expected, the obtained pressure-sensitive material CNT/PEGDA@polyHIPE-SH has a strong interfacial interaction between the substrate and the conductive layer, thus ensuring the good signal stability and durability. The sensor also has a sensitivity of up to −6.45 % kPa−1 and a wide response range from 0 to 400 kPa. Furthermore, the sensors are used as input devices to realize multi-mode HMI, and high-accuracy object recognition at low sensor densities via a convolutional neural network based deep learning model.