Thermotropic Chiral−Nematic Poly(p-phenylene)s as a Paradigm of Helically Stacked π-Conjugated Systems
| Autor: | T. H. Mourey, Dimitris Katsis, S. H. Chen, John C. Mastrangelo, Huang-Ming Chen, Kenneth L. Marshall |
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| Rok vydání: | 2000 |
| Předmět: | |
| Zdroj: | Chemistry of Materials. 12:2275-2281 |
| ISSN: | 1520-5002 0897-4756 |
| DOI: | 10.1021/cm000238m |
| Popis: | As an emerging class of multifunctional optical materials, chiral−nematic poly(p-phenylene)s with cyanobiphenyl and (S)-1-phenylethyl pendants were synthesized and characterized. Nematic homopolymer was also synthesized for preparation into a uniaxially aligned film. Linearly polarized photoluminescence (LPPL) and FTIR dichroism revealed that both the conjugated backbone and the nematic pendant are oriented along the director with an orientational order parameter, S = 0.62 and 0.73, respectively. Films prepared with chiral−nematic copolymers were found to selectively reflect left-handed circularly polarized light in the ultraviolet, visible, and infrared region at a decreasing chiral content. The helically stacked poly(p-phenylene)s were further characterized in terms of circularly polarized photoluminescence (CPPL). On the basis of a recent theory, S = 0.67 was found for the orientational order of conjugated backbones within quasinematic layers comprising the chiral−nematic film. Within experimental unce... |
| Databáze: | OpenAIRE |
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