Characterization of an Optoelectronic Polymer,Poly(2-Phenoxy p -Phenylene Vinylene),and its Precursor Polymer by Dynamic Infrared Spectroscopy

Abstract

Numerous applications of dynamic infrared spectroscopy to study a variety of polymer systems have been described in the literature. Typically, dynamic spectral changes are used to determine the molecular and submolecular reorientations that give rise to a material's observable mechanical properties. In the present study, the normal modes are characterized by their time-dependent response to an applied perturbation as an aid to assignment of the observed vibrational bands. Characterization of a newly synthesized optoelectronic polymer, poly(2-phenoxy p-phenylene vinylene), and its precursor polymer, is described. Vibrational modes along the backbone and side chain are expected to exhibit significantly different responses to mechanical perturbation due to delayed phase response of the phenoxy substituent. In-phase spectra, quadrature spectra, and two-dimensional infrared correlation maps are included in this characterization. This study has demonstrated that dynamic infrared spectroscopy can be used to distinguish backbone phenylene ring stretches from ring stretches associated with the phenoxy substituent. Density functional theory calculations are applied to confirm infrared spectral assignments. The mechanical properties are briefly discussed in light of the dynamic response.