A self-acid-doped and self-cross-linked PEDOT derivative using a simple and effective thiosulfate addition

Despite the massive potential of self-acid-doped materials in a variety of biological and electronics applications, the repertoire of such conjugated polymers remains small and the choice of pendant groups even more limited. We report here a poly(3,4-ethylenedioxythiophene) (PEDOT) derivative synthesized by the simple and effective addition of thiosulfate pendant groups and illustrate its unique design, with the pendant group separated from the backbone by only one methylene side chain spacer. We establish that the polymer is self-acid-doped and highly water-soluble. In addition, we demonstrate its self-cross-linking functionality, which allows for the fabrication of self-acid-doped films without the need for dopants or other additives. These films were stable in water and retained their electrochemical properties. We therefore present the first example of a thiosulfate group used to self-acid-dope and self-cross-link a PEDOT and showcase an easy methodology for flexible modification of polyelectrolyte side chains.