# Revealing the Effect of Pendant Identity on the Electrochemistry of Non‐Conjugated Redox Active Polymers

## TL;DR

This study explores how different redox groups in polymers affect electron transfer, showing that favorable interactions with the solvent enhance charge transfer efficiency.

## Contribution

The work introduces a systematic comparison of three redox pendants with identical polymer backbones to reveal the impact of polymer-solvent interactions on charge transfer.

## Key findings

- The apparent diffusion coefficient and self-exchange rate constant correlate with polymer-solvent favorability.
- Favorable polymer-solvent interactions enhance electron transfer in the solution state.
- A swollen polymer chain conformation promotes solution-state electron transfer.

## Abstract

Understanding charge transfer in redox‐active non‐conjugated polymers is key to unlocking their potential as alternative materials for energy storage. Many factors contribute to charge transfer, such as flexibility of the backbone, redox moiety type, and distance between neighboring redox sites. In a previous work, a series of spatially defined 2,2,6,6‐tetramethylpiperidin‐1‐oxyl (TEMPO)‐containing polymers was reported, with varied spacer lengths between the redox sites. Herein, the synthesis and characterization of spatially defined polymers is reported with the same spacing of three different redox pendants (phenothiazine, phthalimide, and dopamine) and the corresponding electrochemical properties. By doing so, the effect of solution‐polymer interactions (in both the charged and neutral states) is revealed. The apparent diffusion coefficient (D
app), the self‐exchange rate constant (k
ex), and the polymer‐solvent interactions (χ and A2) of the phenothiazine, phthalimide, and TEMPO polymers are compared. The dopamine‐based polymer exhibits limited solubility, preventing further characterization. D
app and k
ex correlate with χ, suggesting that solvent favorability enhances charge transfer in the solution state. These findings highlight the important role that polymer‐solvent interactions play in the transfer of electrons, suggesting that a swollen polymer chain conformation promotes solution‐state electron transfer and that solvent favorability promotes charge transfer.

By examining three different redox‐active polymers with identical backbones, this work demonstrates that redox kinetics correlate strongly with polymer‐solvent favorability, in which favorable polymer‐solvent interactions increase the reaction kinetics© 2025 WILEY‐VCH GmbH