Dresden 2017 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 35: Focus: Polymer Crystallization - from Model Systems to New Materials I

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.