A superhydrophobic wearable rubber band with a synergistic dual conductive layer for monitoring human motions

Wearable and flexible electronics attract increasing attention due to their outstanding stretchability and human friendliness, while the significant parameters to evaluate sensor performance such as sensitivity and working range are the main challenge for better sensor design. Herein, an ultrasensitive and flexible strain sensor with synergistic dual conductive layers was successfully fabricated by designing a silk wrinkles structure to largely broaden the stretchable range for the conductive layer. The organic conductive polypyrrole and silver nanowire are combined to construct the conductive layer with high conductivity and better stretchability. The as-obtained sensor possesses a wide working range (0-126 %) and high sensitivity (a GF of 15710.75 at a strain of 120 %-126 %). The additional SiO2 layer is applied to the sensor to achieve a contact angle of 143.4 degrees, which is close to superhydrophobicity. The resultant sensor also possesses fast response and recovery speed due to the elastomeric rubber band substrate with the response and recovery time of 105 and 101 ms respectively, and still keeps high stability over 5000 cyclic stretching and releasing tests. The sensor is promising to be used in wearable applications potentially.