Photo-thermo-mechanically actuated liquid crystalline elastomer nanocomposite reinforced by polyurethane fiber-network

Abstract

ABSTRACTIn this work, we develop a nanocomposite consisting of nematic liquid crystal elastomer (LCE) matrix incorporated with single-wall carbon nanotubes (SWCNTs) and the reinforcement phase of polyurethane fiber-network (PUFN). The photo-thermo-mechanical actuation of LCE matrix is realized by converting light into heat with assistant of SWCNTs. The PUFN enhances the mechanical properties of the material, thus the actuation capability. Under the irradiation from a wide-spectrum light source with an intensity on the order of 100 mW/cm2, the PUFNs/SWCNT/LCE nanocomposite contracts up to 27% of the original length in several seconds due to the photo-induced strain, and recovers to the original length in several seconds after the light source is switched off. The efficiency of actuation is not light-spectrum dependent. The maximum effective actuation force is about 260 kPa, much larger than that of the LCE material without the reinforcement of PUFNs. The tensile strength and the performance of anti-fatigue failure under multiple reversible actuations are also greatly improved. The mechanism of the actuation capability of LCE material involved in the fiber-network reinforcement phase is studied.