Advanced functional polymers can address urgent needs in energy, environment and healthcare. I will present my research on molecular engineered polymers with desired thermal and electronic properties, and provide fundamental insight into how structure controls these properties. 1) Can common thermally insulating polymers be engineered into highly thermally conductive materials? I will show two affirmative examples. First, certain stretched ultrahigh molecular weight polyethylene (UHMWPE) films transfer heat four times faster than stainless steel . Second, I have developed amorphous polymers with a 10-fold increase in thermal conductivity by engineering both inter- and intramolecular interactions . These results lay the foundation for rational design and synthesis of heat conducting polymers for thermal management, particularly when flexible, lightweight, chemically inert, and electrically insulating thermal conductors are required. 2) Supercapacitors have seen increasing attention in applications of powering miniaturized electronic devices. But it remains challenging to manufacture thin-film supercapacitors with high energy density, because the necessary components scale poorly and are ill-suited for in-plane geometries. I will present a printable thin-film supercapacitor with improved energy density. Starting with the fundamental theory of the physical and chemical processes that occur in charge storage capacitors, I will discuss advanced polymer nanocomposites for ink formulations, enabling the high-speed printing of supercapacitor electrodes at industrial scale. I will conclude with a discussion of future research that will further develop functional polymers for advanced thermal and electrical applications.
Dr. Yanfei Xu is an assistant professor in the Mechanical and Industrial Engineering Department at University of Massachusetts Amherst. She has worked on polymers for thermal management applications at Massachusetts Institute of Technology. Prior to joining MIT, she worked on printable organic electronics, and secured MarieCurie fellowships with major European institutions and companies, including the Max Planck Institute for Polymer Research, Humboldt University, University of Cambridge, Italian National Research Council, Université de Strasbourg, and the headquarters of BASF SE. (Research Website https://blogs.umass.edu/yanfeixu/)
 Nanostructured polymer films with metal-like thermal conductivity. Nature Communications, 10, 1771 (2019).
 Molecular engineered conjugated polymer with high thermal conductivity. Science Advances, 4, eaar3031 (2018).