Nanoparticle Patterning in Polymer Composite Fibers with Forced Assembly Process

Research in nanoparticle-filled polymer composites has evolved over the years in terms of the structure-property relationship. From homogeneous dispersion to an interconnected 3D framework, the ability to pattern nanoparticles during a continuous, scalable fabrication process is essential for various functionalities. In this work, a combination of the forced assembly process and the dry-jet-wet spinning process is developed for generating a series of alternating layered structures. A 100 µm thick fiber consists of alternating polyacrylonitrile (PAN)/carbon nanotube (CNT), PAN/voids, or PAN/boron nitride (BN) layers with minimum layer thickness down to 170 nm. Two materials are extruded through a 3D printed nozzle for layer multiplication during the forced assembly process, followed by coagulation and post-treatments. Through engineering, the alternating layer patterns, mechanical and thermal properties are significantly enhanced compared to composites with homogeneously dispersed nanofillers.