Preparation and orientation behavior of multi‐walled carbon nanotubes grafted with a side‐chain azobenzene liquid crystalline polymer

Key Laboratory of Polymeric Materials and Application Technology of Hunan Province, Key Laboratory of Advanced Functional Polymer Materials of Colleges and Universities of Hunan Province, College of Chemistry, Xiangtan University, Xiangtan 411105, Hunan Province, PR China
Polymer International (Impact Factor: 2.13). 09/2010; 60(1):93 - 101. DOI: 10.1002/pi.2917

ABSTRACT Covalent functionalization of multi‐walled carbon nanotubes (MWNTs) with side‐chain azobenzene liquid crystalline poly{6‐[4‐(4‐methoxyphenylazo)phenoxy]hexyl methacrylate} (PMMAZO) was successfully achieved via atom transfer radical polymerization. The resultant samples were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis and transmission electron microscopy. The results of differential scanning calorimetry and polarized optical microscopy show that the liquid crystalline behavior of PMMAZO‐functionalized carbon nanotubes (CNT‐PMMAZO) is similar to that of the PMMAZO homopolymer. The orientation of MWNTs and CNT‐PMMAZO in a PMMAZO matrix in the presence of an electric field was investigated. The results indicate that the orientation of MWNTs is dominated by the viscosity of the matrix, but the orientation of CNT‐PMMAZO is controlled by both the viscosity and the presence of a liquid crystalline phase ascribed to the compatibility between MWNTs and PMMAZO becoming better after covalent modification. Copyright © 2010 Society of Chemical Industry

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We report the creation of nematic nanotube gels containing large domains of isolated, oriented, half-micron-long, single-wall carbon nanotubes (SWNTs). We make them by homogeneously dispersing surfactant coated SWNTs at low concentration in an N-isopropyl acrylamide gel and then inducing a volume-compression transition. These gels exhibit hallmark properties of a nematic: birefrigence, anisotropy in optical absorption, and disclination defects. We also investigate the isotropic-to-nematic transition of these gels, and we describe the physical properties of their ensuing nematic state, including a novel buckling of sample walls. Finally, we provide a simple model to explain our observations.
    Physical Review Letters 03/2004; 92(8):088303. · 7.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Crossbar arrays of single-wall carbon nanotubes are produced spontaneously in a single step of chemical vapor deposition by simultaneous graphoepitaxy along faceted nanosteps and field-directed growth, perpendicular to each other. The two alignment mechanisms take place selectively on miscut C-plane sapphire and patterned amorphous SiO2 islands, respectively, without mutual interference, producing dense nanotube grids, with up to 12 junctions per square micrometer. This one-step method of orthogonal self-assembly may open up new possibilities for nanotube circuit integration.
    Nano Letters 09/2006; 6(8):1706-10. · 13.03 Impact Factor