Selective dispersion of arc-discharged single-walled carbon nanotubes with polymethyl(crylic acidyl)silane

Abstract

ABSTRACTA water soluble polysilane derivative, polymethyl(crylic acidyl)silane, has been synthesized by the hydrosilylation of crylic acid with polymethylsilane using 2,2′-azobisisbutyronitrile as initiator. After heating in air at a temperature of 673 K and treatment with two-step concentrated acids, arc discharged single-walled carbon nanotubes (SWNTs) are ultrasonically dispersed in the aqueous solution of polymethyl(crylic acidyl)silane, and then subjected to ultracentrifugation to get rid of those insoluble species. Optical absorption spectra show that polymethyl(crylic acidyl)silane has very good dispersing ability toward arc-discharged SWNTs, and metallic SWNTs are preferentially extracted over semiconducting ones in the supernatants. Moreover, Raman spectra evidence that metallic SWNTs with chiral indexes of (15,3) and semiconducting ones with chiral indexes of (12,2) and (11,1) are selectively dispersed in the aqueous solution of polymethyl(crylic acidyl)silane, indicating that polymethyl(crylic acidyl)silane could simultaneously discriminate the metallicity, helical angle, and diameter of SWNTs.