Highly flexible and stretchable MWCNT/HEPCP nanocomposites with integrated near-IR, temperature and stress sensitivity for electronic skin

Abstract

There is an urgent demand for flexible multifunctional sensitive electronic devices in several potential applications, including personalized health monitoring, human motion detection, human–machine interfaces, soft robotics, and so on. Although exciting progress has been witnessed in recent decades, the excessive dependence on inorganic sensors and flexible substrates makes it difficult to attain multi-function sensing and excellent flexibility simultaneously, as well as their complicated fabrication, technical barriers and high cost. Herein, we report on a family of flexible multi-functional sensitive nanocomposites consisting of multi-walled carbon nanotubes (MWCNTs) uniformly distributed in a high elastic form-stable phase change polymer (HEPCP) that exhibit dramatic response to infrared light (IR), temperature and tensile stress in air, together with outstanding flexibility and stretchability. Optimum sensitivity to on/off IR, temperature and tensile stress is demonstrated with electrical conductivity ratios of 103.7, 11.8 and 1084.0 times at room temperature, respectively. The excellent performance of the MWCNT/HEPCP nanocomposites was largely attributed to the cyclic and reversible changes of their MWCNTs conductive network owing to the reversible form-stable phase transitions and high elasticity of the HEPCP substrate, which subsequently affected the thickness of the interfacial HEPCP between adjacent conductive MWCNTs, and thereby the electron tunneling efficiency between the MWCNTs. The novel MWCNT/HEPCP nanocomposites open a new window for multi-function sensing of electronic skin.