Homocoupling Defects in EDOT-Based Polymers: Their Impact on Solution Aggregation, Redox Behavior, and Electrical Conductivity

Direct arylation polymerization (DArP) has emerged as an efficient method to lower the synthetic complexity of conjugated polymers. This work reports the preparation of an EDOT-based conjugated and electroactive polymer by two different DArP routes where the two paths differ by exchanging each monomer’s coupling functionality (−H vs −Br). It was found that the hydrogenated monomer was more likely to homocouple during polymerization, yielding two polymer samples of similar molecular weight and dispersity but different EDOT content. Then, a third polymer intentionally made with excess EDOT content was prepared by copolymerizing with biEDOT. It was found that increasing EDOT content, whether through homocoupling defects or copolymerization with biEDOT, resulted in materials that had lower oxidation potentials, stronger solution aggregation, and higher solid-state electrical conductivities after oxidative doping.