Abstract
The photochemical reaction and molecular reorientation of a novel photosensitive polyester, poly[oxy(4-<i>n</i>-butyl-3,5-benzoate)oxy-1,4-phenylenediacryloyl] (PPDA-C4BZ), which contains <i>n</i>-butyl side groups and 1,4-phenylenediacryloyl units (PDA chromophores) in the main chain, are reported in detail. We applied two-dimensional (2D) correlation analysis for the infrared (IR) and ultraviolet (UV) absorption spectra of nanoscaled films of PPDA-C4BZ to establish the sequence of the photo-induced segmental reorientations that result from UV irradiation. The photochemical reaction was found to have a greater effect on the polymer's main chains than on its side groups and to induce the reorientation of the polymer molecules. In particular, a cycloaddition process occurs first in the PDA chromophore units and then the local reorientation of the polymer molecules is induced. Namely, such photodimerization of the PDA chromophores induces the molecular reorientations of the PDA chromophores and the benzoate units in the main chain. The photo-induced molecular reorientations occur in the following sequence: photodimerization → benzoate units → PDA chromophores → <i>n</i>-butyl side groups. In addition, a two-dimensional map of the first derivatives of the UV absorption spectra with respect to the exposure energy provided evidence of the formation of head-to-head aggregates (i.e., H-aggregates) of PPDA-C4BZ molecules.
PDF Article
More Like This
Cited By
You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.
Contact your librarian or system administrator
or
Login to access Optica Member Subscription