Mechanically Robust and Hydrophobic Poly(3,4-ethylenedioxythiophene)/Silica Hybrid Transparent Film Using Poly(styrenesulfonate-co-allyl methacrylate) as Template Material

Abstract

We report a simple approach to enhance the mechanical stability and the hydrophobic property of the poly(3,4-ethylenedioxythiophene) (PEDOT) transparent conductive films (TCFs) by an in situ sol–gel hybrid approach. Poly(styrenesulfonate-co-allyl methacrylate) [P(SS-co-AMA)] was used as a template material to synthesize PEDOT:P(SS-co-AMA) aqueous dispersion. PEDOT:P(SS-co-AMA)/silica hybrid films were then prepared by thiol–ene click and sol–gel reactions using silane precursors like 3-mercaptopropyltrimethoxysilane (MPTMS), tetraethyl orthosilicate (TEOS) and perfluorooctyltriethoxysilane (POTES). Pristine PEDOT:P(SS-co-AMA) films on glass showed the electrical conductivity (σ) of 0.07 S/cm, while secondary doping with 5% DMSO increased the conductivity to 77.13 S/cm (transmittance over 92%). As silica is introduced, the electrical conductivity of the PEDOT:P(SS-co-AMA)/silica hybrid films decreased and was in the range of 2.27–76.20 S/cm. Furthermore, the silica hybrid films showed transmittance, >92%; water contact angle, >100°; and pencil hardness, >6H indicating improved hydrophobic property and mechanical stability due to the cross-linked silica network, perfluoro octyl moiety and good compatibility between the organic/inorganic phases. The PEDOT-silica hybrid films with good transparency and electrical conductivity and superior hydrophobic and mechanical properties are suitable candidates for durable optoelectronic device applications.