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  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  to our system. A recent implementation of PMUCA on graphics processing units , 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.
 D.M. Huang, R. Faller, K. Do, A.J. Moule, J. Chem. Theory Comput. 6, 526 (2010). (link)
 S. Förster, E. Kohl, M. Ivanov, J. Gross, W. Widdra, W. Janke, J. Chem. Phys. 141, 164701 (2014). (link)
 J. Gross, M. Ivanov, W. Janke, J. Phys.: Conf. Ser. 750, 012009 (2016). (link)
 M. Ivanov, J. Gross, W. Janke, Eur. Phys. J. – Spec. Top. 226, 667 (2017). (link)
 J. Zierenberg, M. Marenz, W. Janke, Comput. Phys. Commun. 184, 1155 (2013). (link)
 J. Gross, J. Zierenberg, M. Weigel, W. Janke, to appear in Comput. Phys. Commun. (2017).