Strain-sensitivity conductive MWCNTs composite hydrogel for wearable device and near-infrared photosensor

Healable, flexible, near infrared sensitive and strain-sensitive for wearable device and healthcare monitoring are successfully formed from sensitive, conductive and biocompatible hydrogels. In this work, a sensitive, mechanically self-healing hydrogel was fabricated via the incorporation of multiwalled carbon nanotubes (MWCNTs) into the hydrophobically associated polyacrylamide hydrogels. As a result, the optimal tensile strength (0.91 MPa) and electrical conductivity (0.5 S m−1) were achieved for the PAM/MWCNTs composite hydrogels. Due to its various functions, the cross-linking hydrogel could be made as a strain sensor. The strain sensor achieved a gauge factor of 5.6, and its response time was 0.3 s. It could be stretched at least for 200 cycles, which was further applied to monitor human movement, including movement of the hands, elbow and even swallowing. With excellent mechanical properties, tensile sensitivity and biocompatibility, the prepared hydrogels could be used as a perfect material for electronic skin. At the same time, flexible and healable PAM/MWCNTs hydrogel had a sensitive near-infrared light response, and we create a new flexible and healable near-infrared light-sensitive photosensor because of the incorporation of MWCNTs, which is different from the traditional NIR photosensor. It could be used in NIR detector, medical instrument and health equipment.