Solution Processable Functional Polymers

First, we aimed to incorporate stable tetracyanocyclopentadienide (TCCp) aromatic ani­ons into polynorbornene-based electrolytes, emphasizing controlled synthesis and properties through ring-opening metathesis polymerization (ROMP). Here, we first successfully incorporate a stable tetracyanocyclopentadienide (TCCp) aromatic anion into polynorbornene (PNb)-based elec­trolytes (PNb-TCCp) through ring-opening metathesis polymerization (ROMP) with controllable molecular weight and low polydispersity. PNb-TCCp shows a high ionic conductivity of 4.5 × 10^–5 S/cm in thin films. Due to its highly stable aromatic anion groups and favorable interactions with aromatic cations, it could improve thermal stability of doped conjugated polymers. Pairing with doped poly(3,4-ethylenedioxythiophene) (PEDOT) through salt metathesis, the generated poly ion complex PEDOT:PNb-TCCp retains its conductivity up to 180 °C.

Second, we aim to develop new photocatalysts for O-ATRP. We discovered a novel one-pot synthetic approach elu­cidates the formation of core-extended N,N′-disubstituted diaryl dihydrophenazine diradical dica­tions (DRDCs) via chemical oxidation. These DRDCs were reduced to their neutral state and found to have photocatalytic abilities, expanding the knowledge for O-ATRP photocatalysts.

Finally, we aim to understand the fundamental structure property relationship of the n-doped n-PBDF. The n-doped poly(benzodifurandione) (n-PBDF) is an n-type conducting polymer with characteristics such as high electrical conductivity, solution processability, and weathering stability. Here, we sys­tematically in­vestigate the structure property relationship on the impact of structural mod­ifications through aromatic substitution on the photophysical, electrical, and structural properties of n-PBDF and its oligomeric derivatives. We demonstrated that an electron donation group (methyl) raised the highest occupied molecular orbital energy level (+0.15 eV), while electron withdrawing halogens (Br and Cl) decreased the lowest unoccupied molecular orbital energy level (−0.12 eV and −0.13 eV, respectively) in the polymers. Additionally, in the both the undoped and doped oligo­meric systems, these substitutions introduce large torsion angles (θ > 17°), causing the material to twist significantly. Moreover, the methyl substituted polymer, n-PBDF-Me, was evaluated for its potential as a transparent organic conductor, due to its high optical transmittance (T₅₅₀ > 93%). However, n-PBDF-Me films have significantly lower con­ductiv­ity than n-PBDF (0.40 S/cm vs 1330 S/cm) at similar thickness.