Structure Formation of Spinning Polymer Fibers Studied by Monte Carlo Simulations*

We performed dynamic Monte Carlo simulations of lattice polymer solutions to investigate the solidification process in a fluid filament after extruded from a spinneret into a coagulation bath. We observed skin-core structure formation under the interplay of phase separation and polymer crystallization. We found that a radial temperature gradient dominates the formation of a highly oriented solid skin, while a radial influx of non-solvent dominates the formation of a concentrated core. The processing parameters can adjust and even eliminate the skin-core structure in the fibers. Our molecular-level observations facilitate a better understanding of the fiber processing for the industry to make high quality fibers.