Poly(benzobisoxazole divinylene): synthesis, photophysical properties, and electron paramagnetic resonance studies

A new conjugated rigid-rod polymer, poly(benzobisoxazole divinylene) (PBODV) has been synthesized and characterized using FTIR, 1H NMR, viscometry, wide-angle X-ray diffraction, and thermogravimetric analysis. UV absorption spectroscopy and photoluminescence spectroscopy were also used to investigate the photophysical properties of these polymers in methanesulfonic acid in detail. The results show that the introduction of trans-vinylene segments into the poly(benzobisoxozale)s backbone narrowed the optical bandgap of this class of polymers. The excitation and emission spectra change significantly with the concentration both in shape and the peak positions, indicating the formation of aggregates in solution. Furthermore, electronic paramagnetic resonance studies show the intrinsic paramagnetic defects in the PBODV, which can be interpreted using a soliton–antisoliton model.