Direct Photopatterning of Electrochromic Polymers

Propylenedioxythiophene (ProDOT) polymers are synthesized using an oxidative polymerization route that results in methacrylate substituted poly(ProDOTs) having a M_n of 10–20 kDa wherein the methacrylate functionality constitutes from 6 to 60% of the total monomer units. Solutions of these polymers show excellent film forming abilities, with thin films prepared using both spray‐casting and spin‐coating. These polymers are demonstrated to crosslink upon UV irradiation at 350 nm, in the presence of an appropriate photoinitiator, to render the films insoluble to common organic solvents. Electrochemical, spectroelectrochemical, and colorimetric analyses of the crosslinked polymer films are performed to establish that they retain the same electrochromic qualities as the parent polymers with no detriment to the observed properties. To demonstrate applicability for multi‐film processing and patterning, photolithographic patterning is shown, as is desired for fully solution processed and patterned devices.