Tensile actuators of carbon nanotube coiled yarn based on polydiacetylene-pluronic copolymers as temperature indicators

Most polydiacetylenes (PDAs) have been studied as chromatic sensors or temperature indicators because of their phase transition that is accompanied by a color change from blue to red. Here, we focus on the structural change based on the polydiacetylene phase transition for a temperature-responsive tensile actuator at low temperature using a copolymer composed of PDA and pluronic in a multi-walled carbon nanotube (MWCNT) coiled yarn. In this paper, we do not focus on the general color change phenomenon of PDA. We demonstrate that the volume change of PDA in the MWCNT coiled yarn provides similar to 180% tensile strain at low temperature (similar to 53 degrees C). Insertion of the pluronic copolymer into the coiled yarn composed of PDA and MWCNT caused the tensile actuation temperature to decrease by similar to 6 degrees C (with tensile actuation of similar to 230%) compared to an actuator without pluronic copolymer. Furthermore, we could verify that the large tensile actuation was also predominantly affected by the melting of the nonpolymerized diacetylene (DA) monomer and the pluronic copolymer. MWCNT coiled yarn actuators with PDA-pluronic copolymer can be easily prepared, have a large tensile actuation, and are actuated at low temperature. It could be used as temperature indicators in the food, drugs, and medical fields.This work was supported by the Creative Research Initiative Center for Self-powered Actuation and the Korea-US Air Force Cooperation Program Grant No. 2013K1A3A1A32035592 in Korea. Support at the University of Texas at Dallas was provided by the Air Force Office of Scientific Research Grants FA9550-15-1-0089 and AOARD-FA2386-13-4119, NASA Grants NNX14CS09P and NNX15CS05C, and the Robert A Welch Foundation Grant AT-0029