title: A new method for the time-resolved analysis of structure and orientation: polarization modulation infrared structural absorbance spectroscopy.
abstract: Polarization modulation infrared linear dichroism (PM-IRLD) is often used for measurements of molecular orientation with high sensitivity and good time resolution. However, PM-IRLD is unable to provide the structural absorbance spectrum because it does not measure separately the parallel and perpendicular spectra. Here we propose a new method, named polarization modulation infrared structural absorbance spectroscopy (PM-IRSAS), to overcome this limitation of PM-IRLD. PM-IRSAS measures the dichroic difference and structural absorbance spectra simultaneously and, therefore, allows quantitative analysis of molecular orientation and conformation with 200 ms time resolution. The PM-IRSAS method was first validated through comparison with conventional polarized FT-IR spectroscopy using drawn polymer films. Second, it was demonstrated that the PM-IRSAS method can provide a quantitative analysis of dynamic orientation and conformation changes in PET films during deformation and crystallization processes.
authors.affiliation: Department of Chemistry, University of Montreal, CP 6128 Station Centre-ville, Montréal, QC, H3C 3J7, Canada.
authors.forename: Yongri
authors.initials: Y
authors.lastname: Liang
authors.forename: Damien
authors.initials: D
authors.lastname: Mauran
authors.forename: Robert E
authors.initials: RE
authors.lastname: Prud'homme
authors.forename: Christian
authors.initials: C
authors.lastname: Pellerin