title: Self-organization of polybases neutralized with mesogenic wedge-shaped sulfonic acid molecules: an approach toward supramolecular cylinders.
abstract: Complexes consisting of poly(4-vinylpyridine) and mesogenic wedge-shaped ligands 4'-[3",4",5"-tris(dodecyloxy)benzoyloxy]azobenzene-4-sulfonic acid and 4'-[3",4",5"-tris(octyloxy)benzoyloxy]azobenzene-4-sulfonic acid have been prepared with different monomer/ligand ratios. Upon protonation of the poly(4-vinylpyridine) chains by the wedge-shaped sulfonic acid molecules a hypsochromic and hyperchromic effect was observed with the pi-pi* transition of the azo-chromophor, allowing us to monitor the neutralization process by means of UV-vis spectroscopy in solution. The changes of the absorption characteristics implied a conformational change of the polymer backbone. In the bulk the interaction between pyridine and sulfonic acid moieties was proved by FT-IR spectroscopy. Polarizing optical microscopy, differential scanning calorimetry, and X-ray diffraction measurements were used to study the bulk structure of the complexes. The complexes formed a liquid crystalline lamellar phase at low degrees of substitution, while a hexagonal columnar mesophase was observed at degrees of neutralization of 80% and higher.
authors.affiliation: DWI an der RWTH Aachen e.V. and Institute of Technical and Macromolecular Chemistry at RWTH Aachen, Pauwelsstrasse 8, D-52056 Aachen, Germany.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Zhu
authors.forename: Uwe
authors.initials: U
authors.lastname: Beginn
authors.forename: Martin
authors.initials: M
authors.lastname: Möller
authors.forename: Raluca I
authors.initials: RI
authors.lastname: Gearba
authors.forename: Denis V
authors.initials: DV
authors.lastname: Anokhin
authors.forename: Dimitri A
authors.initials: DA
authors.lastname: Ivanov