The possibility of intra-molecular nematic order via chain folding in perylene-containing polyimides: a molecular dynamics study

Perylene containing main-chain polyimides are candidate materials for the p hotogenerator layer of electrophotographic devices. These polymers are semi -crystalline as synthesized. Annealing improves the crystallinity while cau sing subtle changes in the X-ray diffraction pattern and a red-shift in the UV-vis absorption spectrum. Molecular dynamics simulations of linear chain s of ...Pe-C-12-Pe... led to chain folded collapsed structures. It is known that a minimum chain length of 150 CH2 units is required, in the case of l inear alkanes, for stable folding to occur. However, the strong attractive rr interaction between the perylene units causes the chain to fold, with as few as 12 CH2 spacer units, This shows that both intra and intermolecular nematic order can occur in these systems, the former caused by chain foldin g. (C) 2000 Elsevier Science Ltd. All rights reserved.