Controlling orientation of V₂O₅ nanowires within micropatterns via microcontact printing combined with the gluing Langmuir-Blodgett technique

Previously, we suggested a facile method to transfer dioctadecyldimethylammonium bromide (DODAB)/V₂O₅ nanowire hybrid patterns onto both hydrophobic and hydrophilic substrates via microcontact printing combined with the Langmuir-Blodgett (LB) technique (Park et al 2007 Nanotechnology 18 405301). Herein, we report on the delicate control of the orientation of V₂O₅ nanowires within the micropatterns transferred via the gluing LB technique using a patterned polydimethylsilicate (PDMS) stamp. According to the orientation of the PDMS line patterns relative to the air-water interface, the aligned orientation of the nanowires, either parallel or perpendicular to the patterns, could be obtained and attributed to the moving direction of the water menisci formed between the PDMS stamp and water. In particular, addition of a small amount of ethanol in the subphase enhanced the dispersion of the DODAB at the air-water interface as well as the aggregation of V₂O₅ nanowires, resulting in alignment of the V₂O₅ nanowires via compression of the hybrid LB film by a barrier. Directional alignment of nanowires has potentially broad applications in the fabrication of aligned nanowire devices.