The oft-utilized design paradigm associated with conducting polymers is one rooted in macromolecules containing large degrees of conjugation along their backbones and the inclusion of chemical dopants that serve to change the oxidation state of the polymers. However, moving from this archetype and towards one with a single-component, charge-neutral macromolecule has significant fundamental and practical benefits, as this type of polymeric conductor should result in materials that can be designed in a less Edisonian fashion and should have longer stability when implemented in devices. In order to address this need, we have designed a series of redox-active macromolecules based on the radical polymer (i.e., macromolecules that are composed of non-conjugated backbones and have pendant groups that contain open-shell entities) design motif. Specifically, we have synthesized poly(4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl) (PTEO) using a ring-opening polymerization methodology (Figure 1) in order to form a radical polymer with a flexible macromolecular backbone and a relatively low (i.e., near room temperature) glass transition temperature. In generating a redox-active macromolecule with a flow temperature far-removed from the degradation temperature of the radical site within the polymer, thermal annealing of the radical polymer thin film resulted in the formation of localized domains with rapid charge exchange reactions. Because this material is able to obtain a local order in the glassy state, a greater than 1,000-fold increase is observed in the electrical conductivity of PTEO relative to all other reports of electrical conductivity in radical polymers. Moreover, the ultimate conductivity of ~20 S m<sup>-1</sup> places this undoped polymer conductor in the same regime as many grades of common commercially-available, chemically-doped conducting polymers. Thus, this work implements a rarely-used design paradigm in order to generate a potentially valuable polymer electronic material.

Designing charge-neutral, non-conjugated radical polymers with high electrical conductivity values

255th National Meeting (2018)

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