Photoalignment of a Bisazodioxodibenzothiophene in a Polyvinylpyrrolidone Matrix
| Autor: | Vladimir Agabekov, V. S. Mikulich, S. N. Larykava, J. D. Chaplanova, E. A. Gracheva |
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| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Spin coating Aqueous solution 010304 chemical physics Polyvinylpyrrolidone Chemistry Condensed Matter Physics Dichroic glass Photochemistry 01 natural sciences Cis trans isomerization 0103 physical sciences medicine Irradiation Thin film Isomerization Spectroscopy Nuclear chemistry medicine.drug |
| Zdroj: | Journal of Applied Spectroscopy. 83:527-533 |
| ISSN: | 1573-8647 0021-9037 |
| Popis: | Photoalignment of thin films of dipotassium 3,7-bis[1-(4-hydroxy-3-carboxylate)phenylazo]-5,5′-dioxodibenzothiophene (AtA-2) that were prepared by spin-coating of dye solutions in H2O and DMF and aqueous solutions of polyvinylpyrrolidone (PVP) was studied. The UV absorption band of the dye cis-isomer, the position and intensity of which depended on the PVP concentration in the stock solutions, was recorded upon irradiation of films of AtA-2 in a PVP matrix [AtA-2(PVP)] with unfi ltered light from a DRT-1000 lamp in a vacuum or an Ar atmosphere. PVP facilitated trans–cis isomerization of AtA-2 and increased the stability of the cis-isomer with respect to thermal relaxation into the initial trans-isomer. The dichroic ratio (DR) of AtA-2(PVP) films irradiated with linearly polarized light (blue LED with λ = 450 nm, I = 15 mW/cm2) increased by 1.5 times as the PVP concentration in the stock solutions increased from 1.0 to 10.0 mass%. The morphology and roughness of the films depended on the nature of the solvents used to prepare them. |
| Databáze: | OpenAIRE |
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