Multi-layer LB films of single-wall carbon nanotubes

Abstract

We propose a new processing technique of single-wall carbon nanotubes (SWNTs), namely, multi-layer Langmuir–Blodgett (LB) films. Solubilized SWNTs dispersed in an amphiphilic polymer matrix were spread on a water surface and vertically deposited on substrates. Optical absorbance at 1820 nm was perfectly proportional to the number of layers, demonstrating the successful, layer-by-layer growth of SWNT thin films. Moreover, polarized absorption and Raman spectra indicated a certain degree of tube orientation in the dipping direction. It was also possible to deposit LB films without the polymer matrix, though the film stability was somewhat lowered. Realization of SWNT thin films with precisely controlled thicknesses and optical transparency can be an important breakthrough for both basic understanding and technological applications of this novel form of carbon.