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.

Inorganic Electron Transfer: Sharpening a Fuzzy Border in Mixed Valency and Extending Mixed Valency across Supramolecular Systems

“…35−37 Dynamic 1D IR band-shape coalescense has also been reported in the delocalized states of poly(aniline) and poly(2-phenoxy-pphenylenevinylene) conducting polymers. 38 Time-resolved 2D IR spectroscopy is a very promising method to study very fast dynamical processes, such as those of interest in our work. There are two widely employed techniques in the 2D IR community: vibrational-echo 2D IR 39,40 and dynamic hole burning, or double-resonance 2D IR.…”

“…Strauss has argued that “pseudocollapse”, the progressive broadening of bands arising from an anharmonic potential, causes shifts and broadening of bands in the vibrational spectra that are not due to a chemical exchange reaction . Certainly, the most important and well-known examples of “dynamic IR” are the studies of (η 4 -diene)Fe(CO) 3 systems that were reported to undergo turnstile-like pseudorotation on the picosecond time scale by Grevels and Turner. − The work of Cannon on triiron acetate clusters is also particularly relevant. − Dynamic 1D IR band-shape coalescense has also been reported in the delocalized states of poly(aniline) and poly(2-phenoxy- p -phenylenevinylene) conducting polymers …”