Monte Carlo studies of polymer aggregation

J. Gross and W. Janke

Institut für Theoretische Physik, Universität Leipzig, Postfach 100 920, D-04009 Leipzig, Germany

Poly(3-hexylthiophene) (P3HT) is a semiconducting polymer that has applications in organic photovoltaics. It is widely used as a semiconducting layer in organic thin film field effect transistors (FETs) and solar cells.
We found that a recently developed coarse-grained model [1] of P3HT, is suitable and able to reproduce not only fully atomistic simulations, but also experimental results [2-4]. On the basis of those single-chain studies, we now take the next step and look at aggregation of a few polymers, to gain an understanding of the fundamental processes that happen during the crystallization of P3HT. With replica-exchange (parallel tempering) simulations we investigate a system of four P3HT polymer chains with 10 repeat units each in the presence of a Au(001) surface and without a substrate.
In addition to that, we aim to apply the parallel multicanonical (PMUCA) sampling method [5] to our system. A recent implementation of PMUCA on graphics processing units [6], promises vast increase in efficiency of the multicanonical weight recursion and production run. An early implementation for polymer aggregation using this novel approach is presented here.

[1] D.M. Huang, R. Faller, K. Do, A.J. Moule, J. Chem. Theory Comput. 6, 526 (2010). (link)
[2] S. Förster, E. Kohl, M. Ivanov, J. Gross, W. Widdra, W. Janke, J. Chem. Phys. 141, 164701 (2014). (link)
[3] J. Gross, M. Ivanov, W. Janke, J. Phys.: Conf. Ser. 750, 012009 (2016). (link)
[4] M. Ivanov, J. Gross, W. Janke, Eur. Phys. J. – Spec. Top. 226, 667 (2017). (link)
[5] J. Zierenberg, M. Marenz, W. Janke, Comput. Phys. Commun. 184, 1155 (2013). (link)
[6] J. Gross, J. Zierenberg, M. Weigel, W. Janke, to appear in Comput. Phys. Commun. (2017).