Variable-color poly(3,4-propylenedioxythiophene) electrochromics from precursor polymers

We have developed two approaches to processable precursors to conjugated polymers: main-chain and side-chain. Upon oxidative conversion to the conjugated polymer, a main-chain precursor yielded a nearly perfect spectral match, an identical λmax, and an equivalent band gap to that of electrodeposited chromophore, resulting in a color match. This precursor method has the potential to incorporate any chromophore and achieve spectral and color matching with relative ease, as opposed to extensive synthetic monomer design. We describe the synthesis and characterization of a new side-chain and two new main-chain precursor polymers, each of which contains a derivative of 3,4-propylenedioxythiophene, ProDOT-Me2. The side-chain precursor tethers one ProDOT-Me2 molecule to a poly(norbornene) backbone; the main-chain systems are perfectly alternating copolymers of ProDOT-Me2, one with dimethylsilane and one with tetramethyldisiloxane. Electronic and optical properties for these converted precursors were described and compared to electrodeposited PProDOT-Me2.