Simulation\nof Polymer Fractal Formation Using a Triangular\nNetwork Growth Model

Fractal formation\nin spin-coated thin-film polymers is\nof experimental\nand theoretical interest. Modeling the determinants and dynamics of\nthis process will deepen our understanding of polymer aggregation\nand the predictability of thin-film structures. This is especially\ntrue if the model used has readily interpretable parameters and has\nbeen demonstrated to yield a close match to experimental processes\nunder a variety of conditions. In this work, we adapted and applied\na relatively new model of fractal growth comprised of a spreading\nand contracting triangular network, to model spin-coated, thin-film\npolymers made of poly(vinyl alcohol) on polydimethylsiloxane substrates.\nWe drew clear connections between model parameters and the process\nof polymer aggregation and we demonstrated the ability of the model\nto simulate fractal formation under a wide variety of conditions including\nvarying the degree of hydrolysis of the polymer, changing the spin-coating\nprocess, and solvent annealing and reforming of polymer fractals under\ndifferent drying conditions. We also showed how the model is able\nto replicate idiosyncratic experimental settings yielding novel fractal\npatterns.