Thickness and density controllable pattern transfer of DODAB/V ₂O₅ nanowire hybrid film

We devise a facile method for transferring DODAB/V₂O₅ nanowire hybrid patterns onto hydrophobic as well as hydrophilic substrates via μ-contact printing combined with the Langmuir-Blodgett technique. For the formation of a uniform film of V₂O₅ nanowires on a water surface that are well dispersed in the water, a Langmuir-Blodgett (LB) film of dioctadecyldimethylammonium bromide (DODAB) molecules was used as surfactant. Transfer of the well-ordered LB film of DODAB/V₂O₅ nanowires onto the patterned polydimethylsilioxane (PDMS) stamp via the Langmuir-Schaefer method and subsequent stamping of PDMS onto the 3-aminopropyltriethoxysilane-treated SiO₂ and thin flexible polycarbonate substrates resulted in the fabrication of hybrid film patterns. The density and thickness of the hybrid film patterns were controllable in a layer-by-layer mode by changing the surface pressure of the LB film and the number of stampings, respectively. The electrical conduction through the hybrid film in the pattern was dependent on the density of V₂O₅ nanowires. Such a facile pattern transfer method can be applied to the fabrication of patterned nanowire devices without any chemical modification of the nanowire surfaces.