A Stretchable and Bendable CNT-based Resistive Pressure Sensor

Flexible electronics has directed development and research of unique instrumentation and measurement to achieve conformable sensors for a wide range of applications. Conventional high-performance electronic materials such as silicon are not flexible, whereas flexible materials such as conducting polymers, are often characterized by poor electric properties. Thus, high mobility materials in a flexible configuration are desirable, and carbon nanotubes (CNTs) are promising due to their excellent electric properties and flexibility. Here, we present an all-solid state flexible and stretchable pressure sensor composed of vertically aligned CNTs (VACNTs) partially embedded in polydimethylsiloxane (PDMS). VACNTs are grown via chemical vapor deposition (CVD) and transferred onto PDMS as a stretchable electrode. Two electrodes are placed face-to-face and increased pressure is directly proportional to a detectable change in resistance, enabled by increased contact between opposing electrodes. The resistance is maintained at stretching up to 180%, with a rapid response time during loading and unloading. As a proof-of-concept, the sensor is successfully tested for medical and e-skin applications by measuring biological signals of a person.