Di- and tri-aminosilane SAM-assisted patterning of highly pure poly(3,4-ethylenedioxythiophene) nanofilms robustly adhered to silicon oxide substrate

To improve the patternability and adhesion of pure poly(3,4-ethylenedioxythiophene) (PEDOT) nanofilm to an SiO2 surface, oxidized silicon wafer substrates were micro-contact printed with an n-octadecyltrichlorosilane (OTS) monolayers, and subsequently its negative patterns were self-assembled with N-(2-aminoethyl)-aminopropyltrimethoxysilane (EDAS), and (3-trimethoxysilylpropyl)diethylenetriamine (DETAS) molecules, respectively. Then, PEDOT nanofilms were selectively grown on the each of both monolayer-patterned areas via the vapor phase polymerization method. To evaluate the adhesion and patterning, the PEDOT nanofilms and mixed monolayer were investigated with a Scotch® tape peel test, contact angle analyzer, X-ray photoelectron spectrometer, and optical and atomic force microscopes. The evaluation revealed that the newly developed bottom-up patterning process can offer robustly adhered and finely patterned PEDOT nanofilms showing a noticeably good electrical conductivity (∼ 500 S/cm) on both di- and tri-aminosilane SAM-patterned surfaces. As a result, this study clearly demonstrated that the highly pure PEDOT nanofilm could be employed as a key component in a commercial hybrid organic electronic device in the very near future.