Highly anisotropic molecular thin films prepared by oriented growth on poly(tetrafluoroethylene) surfaces

Citation
T. Tanaka et al., Highly anisotropic molecular thin films prepared by oriented growth on poly(tetrafluoroethylene) surfaces, LANGMUIR, 17(7), 2001, pp. 2192-2198
Citations number
36
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
LANGMUIR
ISSN journal
0743-7463 → ACNP
Volume
17
Issue
7
Year of publication
2001
Pages
2192 - 2198
Database
ISI
SICI code
0743-7463(20010403)17:7<2192:HAMTFP>2.0.ZU;2-1
Abstract
Highly anisotropic molecular thin films have been successfully prepared by depositing bisazo dyes under vacuum through evaporation on an oriented poly (tetrafluoroethylene) (PTFE) surface aligned by rubbing or a friction-trans fer technique. Polarized absorption spectra (UV-visible and IR), electron d iffraction, optical microscopy, and Raman scattering were employed to inves tigate the molecular orientation in the films. The results indicate that th e dye molecules are oriented with their long axes parallel to the PTFE chai ns and that their phenyl rings are fairly parallel to the substrate surface . Slight modifications of the dye molecules lead to significant changes in the degree of the orientation. In particular, the films from a bisazo dye c ontaining a pyrrolidinyl group exhibit a remarkable orientation, showing di chroic ratios up to 130 on the polarized UV-visible spectra.