Significantly improved adhesion of poly(3,4-ethylenedioxythiophene) nanofilms to amino-silane monolayer pre-patterned SiO2 surfaces.

This study reports a novel patterning method for highly pure poly(3,4-ethylenedioxythiophene) (PEDOT) nanofilms having a particularly strong adhesion to a SiO2 surface. An oxidized silicon wafer substrate was micro-contact printed with n-octadecyltrichlorosilane (OTS) monolayer, and subsequently its negative pattern was self-assembled with three different amino-functionalized alkylsilanes, (3-aminopropyl)trimethoxysilane (APS), N-(2-aminoethyl)-3-aminopropyltrimethoxy silane (EDAS), and (3-trimethoxysilylpropyl) diethylenetriamine (DETS). Then, PEDOT nanofilms were selectively grown on the aminosilane pre-patterned areas via the vapor phase polymerization method. To evaluate the adhesion and patterning, the PEDOT nanofilms and SAMs were investigated with a Scotch tape test, contact angle analyzer, optical and atomic force microscopes. The evaluation revealed that the newly developed bottom-up process can successfully offer a strongly adhered and selectively patterned PEDOT nanofilm on an oxidized Si wafer surface.