A correlated method for quantifying mixed and dispersed carbon nanotubes: analysis of the Raman band intensities and evidence of wavenumber shift

We present an experimental investigation of a correlated quantitative analytical method based on advanced Raman spectroscopy. This method was developed for the intensity weight distribution analysis of mixed and dispersed carbon nanotube (CNT) mixtures. For Raman spectroscopy, mixtures of single-walled CNTs (SWNTS) and multi-walled CNTs (MWNTs) were prepared and dispersed on a coverslip. Mixtures were made in the range from 1 to 100 mg (wt%) of SWNTs in 100 to I mg (wt%) of MWNTs. The ratios of the relative intensities of the Raman bands corresponding to pure SWNTs and pure MWNTs were used for the construction of calibration curves used for quantitative analysis. The relative intensity of the deconvoluted spectral bands shows a characteristic feature at 1350 and 1592 cm(-1) which was found to be proportional to the relative amounts of SWNTs and MWNTs in the mixtures. A correlation between the atomic force microscopy images and the tangential mode Raman intensity ratio was used without the need for other analytical techniques. With this feature, it is possible to quantify the different components in the mixed, dispersed or unknown bulk of the CNTs investigated. Copyright (c) 2005 John Wiley & Sons, Ltd.