Thin polymer films (~ 1-10 um) incorporating singly dispersed, vertically aligned carbon nanotubes have a diverse set of potential applications. This project aims to direct the vertical alignment of SWNTs in thin films by using magnetic field aligned lyoptropic surfactant mesophases as structure directing templates. The short alkyl tails of the surfactant impart negative diamagnetic anisotropy to worm-like micelles and lead to parallel alignment of the liquid crystalline (LC) director in an applied magnetic field. The nanotubes orient preferentially with their long axis parallel to the director field of the mesophase, thus promoting their vertical alignment in the system. The LC mesophase incorporates monomers that are polymerized by UV exposure after nanotube alignment to form the polymer matrix. X-ray scattering and optical spectroscopy are used to characterize the field-guided assembly process.
LC Alignment under Magnetic Field: Microscopic observation of hexagonally ordered host matrix viewed under polarized microscope before and after alignment.
Wide Angle X-ray Scattering of Host Matrix: Alignment of wormlike micelles in the direction of the applied field evident from enhanced intensity along vertical axis. Scattered intensity vs. scattering vector derived by circular integration of the WAXS scattering pattern. The ratios of the q vectors indicate that the sample is composed of hexagonally packed cylinders.
