Directed crystallization of a poly(3,4-ethylenedioxythiophene) film by an iron(III) dodecyl sulfate lamellar superstructure

Abstract The synthesis and properties of the poly(3,4-ethylenedioxythiophene):dodecyl sulfate (PEDOT:DS) film are presented and its directed crystallization is described. Iron(III) dodecyl sulfate (Fe(DS)3) multi-lamellar vesicles (MLVs), a newly introduced growth template and a key factor upgrading the vapor-phase polymerization (VPP) of 3,4-ethylenedioxythiophene (EDOT), was used to synthesize a highly conductive, transparent, and mechanically durable film specifically suitable for next-generation flexible electronics. The PEDOT film formed with Fe(DS)3, and doped with DS anions, is highly transparent, metallically conductive (max. ~1.1 × 104 S cm-1), and mechanically highly durable but still flexible. These outstanding physical properties of the VPP-PEDOT film exclusively originate from the MLVs of Fe(DS)3, which have a lamellar superstructure, and simultaneously play several advantageous roles during VPP: a highly effective oxidant without side reactions, a highly efficient in-situ dopant, a template for large-scale crystal growth, and an enhancer of water resistance and durability. The crystal growth of PEDOT is directed by several hundred micrometer-sized lamellar planes of the densely packed Fe(DS)3 surfactant molecules to fabricate a PEDOT:DS co-crystal of approximately the same size. These findings provide a new direction for the synthesis of more conductive, transparent, robust, and flexible polymer electrode materials in future by constructing MLV-type oxidants with a more sophisticated design.