Dresden 2017 – wissenschaftliches Programm
CPP 35.4: Vortrag
Mittwoch, 22. März 2017, 11:00–11:15, ZEU 222
Impact of Molecular Dynamics on Structure Formation of Donor-Acceptor Block Copolymers — •Matthias Fischer1, Christian David Heinrich2, Mukundan Thelakkat2, and Thomas Thurn-Albrecht1 — 1Martin Luther University Halle-Wittenberg — 2University of Bayreuth
Donor-Acceptor block copolymers (BCP) are attractive materials for organic photovoltaics due to their intrinsic property to form an equilibrium nanostructure on the length scale of exciton diffusion. As usually semiconducting polymers are crystalline or liquid crystalline structure formation is complex in these BCPs. We here present a study of the interplay between phase separation, crystallization and glass transition in two donor-acceptor BCPs of poly(3-hexylthiophene)-block-poly perylene bisimide (P3HT-b-PPBI) incorporating P3HT as donor and polystyrene with two different pendant perylene bisimides as acceptor. In order to study the effect of backbone glass transition on side chain crystallization in the acceptor block low molecular weight model compounds, homopolymers and BCPs were compared using differential scanning calorimetry and temperature dependent wide- and small-angle x-ray scattering as central methods. While microphase separation in the liquid state led to a cylindrical morphology in both cases the crystallization of the side chains depended strongly on the backbone glass transition temperature as compared to the ordering temperature of the PBI units. Surprisingly, a strong π-π-interaction was found even in the absence of lateral ordering of the side chains possibly explaining the relatively high electron mobility of these disordered materials.