Fabrication of carbon nanotube thin films by surface engineering

We have investigated uniform carbon nanotube (CNT) dispersion in a solution and fabrication of CNT thin films on solid surfaces. To prevent bundle formation, we have examined surface modification of both the CNT surfaces and the substrate surfaces. To enhance the interaction between surfaces of the substrate and the CNTs, the substrate surfaces were made hydrophobic, because CNTs are generally hydrophobic. When CNTs were dispersed on the hydrophobic surfaces, relatively uniform CNT thin films were formed. To weaken the interaction between the individual CNTs, CNT surfaces were coated with synthetic polymers or biomolecules. Amphiphilic, ionic polymers with π-stacking are most suitable for CNT solubilization in a polar solvent. High-density well-dispersed CNT thin films were fabricated by modifying CNT surfaces with single-stranded DNAs.