Alignment of Single-Walled Carbon Nanotubes with Ferroelectric Liquid Crystal

Single-walled carbon nanotubes (SWCNTs) are aligned by using a ferroelectric liquid crystal (FLC) named [4-(3)-(S)-methyl-2-(S)-chloropentanoyloxy)]-4'-nonyloxy-biphenyl. The scanning electron microscope (SEM) is utilized to investigate the alignment of the SWCNTs in the smectic A phase. Fourier Transform Infrared spectroscopy (FTIR) and Raman spectroscopy are utilized to investigate the interaction between these two species. The SEM images show that SWCNTs can be well aligned along the smectic layers. A new peak appears at 1702 cm(-1) in the FTIR spectra in the SWCNT hybrids, which indicate that charge transfer occurring from the hexagonal rings of the SWCNTs to the C=O groups of the FLC molecules that contact directly with the SWCNTs. To our knowledge, this is the first time we observe the charge transfer effect by FTIR Similarly, a new peak at 763 cm(-1) is also found in the Raman spectrum of the SWCNT hybrid that results from the charge transfer effect between the SWCNTs and the C-Cl groups of the FLC. The pi-pi stacking and charge transfer effect together make the SWCNTs align unidirectionally along the smectic layers instead of in the direction of the molecular long axis.