Directed assembly of high density single-walled carbon nanotube patterns on flexiblepolymer substrates

Abstract

We report an effective technique for the controlled assembly of single-walledcarbon nanotubes (SWNTs) and demonstrate organized high density networkarchitectures on soft polymeric substrates. We utilize the surface energy differentialbetween a plasma treated (hydrophilic) parylene-C surface and a photoresist(hydrophobic) surface to create microscale patterns of SWNT networks on a 10 µm thick parylene-C substrate. The large scale fabrication of patterned SWNTstructures presented is achieved by performing site-selective fluidic assembly ofSWNTs. Electrically continuous nanotube network micro-arrays as small as 4 µm wide that areup to 1500 µm long with controlled separation have been fabricated by dissolving the photoresist afterassembly. Electrical and mechanical characterization of nanotube networks on the flexiblesubstrate in both static and dynamic modes indicates that the structure can handle bothcompressive and tensile deformations with no hysteresis. The technology presented hasimmediate applications in making thin film transistors, interconnects and sensors onflexible substrates.