Skin-attachable and flexible MWCNT grid/Ecoflex strain sensors with fast equilibrium of response for detection of sound vibrations and human motions

Skin-attachable and flexible strain sensors have attracted extensive interests because they enable to monitor individual physical actions, health status, and vibrations of sound. In this paper, multi-walled carbon nanotubes (MWCNTs) are transfer-printed into Ecoflex substrate to fabricate the MWCNT grid/Ecoflex strain sensors. We investigated the effects of the distribution and amount of MWCNTs on the sensor properties by tuning mesh sizes of nylon screens and repeated times of spray-coating and found that the distribution and amount of MWCNTs could influence on the response equilibrium process of sensors, besides the response value. Among the as-prepared samples, the sensors based on 75-mesh screens with 20-time coating exhibit the fastest equilibrium of response with a relatively high response, which the response time is about 274 ms. Meanwhile, the sensors have a good stability and durability. Furthermore, the as-prepared attachable and flexible strain sensors are capable of monitoring different finger gestures, diverse subtle motions of human body, and vibrations of sound, which demonstrate an application prospects in the fields of human motion detection, electronic skins of bionic robots, and human–machine interfaces.