|Kohn, P.; Ghazaryan, L.; Gupta, G.; Sommer, M.; Wicklein, A.; Thelakkat, M.; Thurn-Albrecht, T.: Thermotropic Behavior, Packing, and Thin Film Structure of an Electron Accepting Side-Chain Polymer, Macromolecules, 45(14), 5676-5683 (2012) -- DOI: 10.1021/ma3010197|
We report on the phase behavior and the structure of poly(perylene bisimide acrylate), an electron accepting semiconductor polymer with disclike side-chain units, in comparison to the corresponding low molecular weight perylene bisimide. By combination of DSC, optical microscopy, and temperature-dependent small-angle and wide-angle X-ray scattering, we show that both compounds display a lamello-columnar packing. While the perylene bisimide model compound crystallizes, the polymeric architecture of poly(perylene bisimide acrylate) suppresses order, leading to a 2D lamello-columnar liquid crystalline phase. The structure of the side-chain polymer in thin films with different thermal treatments as observed by GIWAXS correlates well with previously observed largely different electron mobilities. Such a polymeric, liquid crystalline compound combines the advantages of molecular order and easy processability, together with the film forming properties of polymeric materials.