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A new theoretical approach for the determination of molecular orientation persistence length of adsorbed nanofilms by FTIR reflectance spectroscopy
Author(s) -
Brogly Maurice,
Bistac Sophie,
Schultz Jacques
Publication year - 1998
Publication title -
macromolecular theory and simulations
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 56
eISSN - 1521-3919
pISSN - 1022-1344
DOI - 10.1002/(sici)1521-3919(19980101)7:1<65::aid-mats65>3.0.co;2-p
Subject(s) - specular reflection , persistence length , reflection (computer programming) , orientation (vector space) , isotropy , infrared , attenuated total reflection , fourier transform infrared spectroscopy , materials science , optics , diffuse reflection , chemistry , refractive index , infrared spectroscopy , spectroscopy , polarization (electrochemistry) , diffuse reflectance infrared fourier transform , molecular physics , molecule , geometry , physics , mathematics , organic chemistry , quantum mechanics , photocatalysis , catalysis , biochemistry , computer science , programming language
FTIR‐Reflectance experiments have proved to be a powerful tool for the determination of molecular orientation in thin films adsorbed onto highly reflecting metals. We propose an original method for determination of the persistence length of molecular orientation in the film. This approach is based on the fact that molecular orientation persists only over a given distance from the geometrical interface. This distance is called the “persistence length of molecular orientation”. We then suppose that the nanofilm adsorbed is stratified and consists of an oriented layer (in the near‐interface region) plus an isotropic one. Correlation between infrared reflection absorption band intensities and simulated band intensities allows experimentators to determine accurate molecular orientation and persistence length of orientation of a considered functional group. This is accomplished by using various IR reflection angles and p‐polarization state of the incident IR wave. Film thickness and complex refractive index spectra, n ( v ) − i · k ( v ), are only needed to deduce calculated specular reflectance intensities.