Reprogrammable and Active Multilayer Responsive Materials Based on Ultrahigh Molecular Polyethylene

Abstract We have developed actively responsive materials that change their shape using hybrid multilayer structures based on the ultra-high molecular polyethylene films (UHMWPE) and copper networks. The fabrication method that is presented combines uniquely low-cost films, layer-by-layer techniques and mass production manufacturing methods from the electronic industry. Through this fabrication method, large-scale responsive surfaces can be developed. Their initial shape can be re-programmed after triggering, while the material remains functional. The developed responsive materials are activated due to the Joule-heating effect on the copper network, when an electrical voltage is applied. The geometry changes drastically due to the induced thermal stresses of the multilayer structure and the anisotropic thermo-mechanical properties, while their shape can be re-programmed in-situ without forming tools. Using X-ray diffractometry, we found that thermal annealing controls the intensity of specific crystalline planes of the polymeric film, leading to specific fabrication protocols in order to achieve great reversibility and resistance to thermal cycling fatigue. Through the integration of low-cost UHMWPE films and by controlling their crystalline structure, the materials can operate at higher temperature levels with great reversibility and sensitivity. These materials can be used in real engineering applications, where soft actuators are important, because of their versatile design and high thermal fatigue resistance.