Journal of Polymer Science, Part A: Polymer Chemistry
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Redox-active 6-oxoverdazyl polymers were synthesized via ring-opening metathesis polymerization (ROMP) and their solution, bulk, and thin-film properties investigated. Detailed studies of the ROMP method employed confirmed that stable radical polymers with controlled molecular weights and narrow molecular weight distributions (Ð < 1.2) were produced. Thermal gravimetric analysis of a representative example of the title polymers demonstrated stability up to 190 °C, while differential scanning calorimetry studies revealed a glass transition temperature of 152 °C. Comparison of the spectra of 6-oxoverdazyl monomer 12 and polymer 13, including FT-IR, UV-vis absorption, and electron paramagnetic resonance spectroscopy, was used to confirm the tolerance of the ROMP mechanism for the 6-oxoverdazyl radical both qualitatively and quantitatively. Cyclic voltammetry studies demonstrated the ambipolar redox properties of polymer 13 (E1/2,ox = 0.25 and E1/2,red = −1.35 V relative to ferrocene/ferrocenium), which were consistent with those of monomer 12. The charge transport properties of thin films of polymer 13 were studied before and after a potential of 5 V was applied, revealing a drastic drop in the resistivity from 106-1010 W×m or more to 1.7 ´ 104 W×m and suggesting the potential usefulness of polymer 13 in bistable electronics.