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Raman tensor analysis of hexagonal polyoxymethylene and its application to study the molecular arrangement in highly crystalline electrospun nanofibers
Author(s) -
Puppulin Leonardo,
Kotaki Masaya,
Nakamura Morimasa,
Iba Daisuke,
Moriwaki Ichiro,
Pezzotti Giuseppe
Publication year - 2012
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4116
Subject(s) - polyoxymethylene , raman spectroscopy , materials science , molecular vibration , orientation (vector space) , normal mode , tensor (intrinsic definition) , nanofiber , distribution function , vibration , nanotechnology , geometry , optics , physics , thermodynamics , mathematics , polymer , composite material , quantum mechanics
The orientation dependence in space of Raman‐active vibrations in the hexagonal structure of polyoxymethylene (POM) is discussed in terms of Raman tensor elements as intrinsic physical parameters of the lattice. The variation of polarized intensity for the A 1 and the E 1 vibrational modes with respect to the POM molecular orientation is systematically studied, from both theoretical and experimental viewpoints, according to the symmetry assignments of each vibrational mode. A set of working equations including the Raman selection rules associated with the A 1 and the E 1 modes and the orientation distribution function are explicitly formulated and validated by means of a least‐square fitting procedure on experimental data. In addition, an approach based on the introduction of orientation distribution functions is applied to quantitatively assess and compare on a statistical base the molecular orientation of two different types of electrospun POM nanofibers. Copyright © 2012 John Wiley & Sons, Ltd.