Synthesis and photochemistry of a 2,6-dialkoxyanthracene-containing, side-chain-substituted liquid-crystalline polymer
Polymers and High Performance Materials
The synthesis and several aspects of the photophysical and photochemical behavior of a methacrylate polymer substituted, via a flexible methylene chain, with a 2,6-dialkoxyanthracene chromophore are reported. Polarized light microscopy and DSC indicate the polymer is liquid crystalline. The UV-Vis and fluorescence spectra of the polymer indicate both ground and excited state aggregation of the chromophores as evidenced by perturbations of these spectra relative to those of a simple model compound. Chromophore association in the ground state seems to occur even in a good solvent, dichloromethane. Chromophore aggregation effects are enhanced in films of the polymer, particularly after heating or when poor solvents are added to a solution of the polymer in dichloromethane. Steady state and time-resolved fluorescence experiments indicate significant self-quenching of the excited anthracene chromophore even in highly diluted solutions in dichloromethane and the presence of a long-lived (tau = 30.6ns) intramolecular excimer or excited aggregate and a short-lived (tau = 2.0ns) anthracene singlet state. At higher concentrations an intermolecular excimer or excited aggregate is observed. Fluorescence spectra of films indicate the presence of weakly emissive excimers or excited aggregates. Two types of 4 + 4 photocycloaddition products are most likely formed upon UV or visible light irradiation. Photooxidation products are also formed when irradiation is carried out in the presence of oxygen.
(1995). Synthesis and photochemistry of a 2,6-dialkoxyanthracene-containing, side-chain-substituted liquid-crystalline polymer. MICROELECTRONICS TECHNOLOGY, 614, 504-517.
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