Shape memory-enhanced water sensing of conductive polymer composites

Electrically conductive polymer composites have been widely utilized as the sensory materials being capable of response to various types of stimuli. A shape memory-enhanced water sensing was unprecedentedly reported for polymer composites comprising of carbon nanotubes (CNTs) and shape memory polyurethane (SMPU). The morphological, thermal, mechanical and micro-structural properties of the CNT-SMPU composites were investigated. Two swelling processes were specifically designed to measure the water sensing of the composites. It was found that the shape memory thermo-mechanical programming enlarged magnitudes of the resistivity variation, which may be attributed to the combination of the swelling effect and the re-orientation/local movements of the CNTs along with stress/strain energy release. The findings may greatly benefit the applications of the smart polymers in the fields of sensory materials and flexible electronics.