One-Pot Synthesis of Aqueous PEDOT-Based Conductive Inks via Sequential RAFT/Oxidative Polymerization

The rising demand for flexible and printable electronics has driven significant interest in π-conjugated polymers, in particular for poly(3,4-ethylenedioxythiophene) (PEDOT), which is traditionally stabilized by poly(styrenesulfonate) (PSS). In the recent years, our group has been investigating poly[4-styrenesulfonyl(trifluoromethylsulfonyl)imide] (PSTFSI) as a promising alternative polyelectrolyte, yielding PEDOT:PSTFSI dispersions with enhanced ionic conductivity, reduced acidity, and lower hygroscopicity. Although this polymer complex offers great potential in organic electronics, its synthesis still requires long reactions times (up to several days) and the use of toxic organic solvents with tedious intermediate purification steps, limiting its scalability and sustainability. Herein, we report an innovative aqueous one-pot synthesis of PEDOT:PSTFSI dispersion, by combining reversible addition-fragmentation chain-transfer (RAFT) and oxidative polymerization in an aqueous one-pot process. This approach eliminates the need for harmful solvents and intermediate purifications, achieving full monomer conversion in less than 4 h and excellent control over macromolecular structure of PSTFSI (30-300 kg mol^-1 with Đ often below 1.1). Following the one-pot oxidative polymerization, the resulting PEDOT:PSTFSI dispersions exhibit filamentous network morphologies, forming highly percolated conductive films upon printing, with charge conductivities up to 120 S cm^-1.