Multi-walled carbon nanotubes (MWCNT) and other carbon nanofillers are used in different applications to enhance the materials and electrical properties of consumer products such as polymer composites. As a result, concern has arisen regarding the potential for nanoparticle release from the surface of nanocomposites. To address this concern, a methodology was developed to (A) detect and (B) characterize dispersion properties of MWCNT at the polymer composites surface by imaging X-ray photoelectron spectroscopy (XPS)1. The presentation will demonstrate how 1%, 4%, and 5% MWCNT-epoxy composites were characterized using XPS by taking advantage of the disparate electrical conductivity of the starting materials. Specifically, by employing differential charging, conductive regions could be identified by XPS imaging. Raman spectra and SEM imaging were employed to corroborate the XPS based evidence that these conductive regions were MWCNT rich. In this proceedings, the potential for semi-quantitative characterization of the MWCNT composites using imaging XPS is explored. A set of parallel images were acquired under charge neutralization of a 4% MWCNT composite as described in the previous paragraph. Both in-house analysis and commercially available XPS software was employed to qualitatively identify regions of low and high surface conductivity. By extracting spectra from regions of low and high electrical conductivity, a set of line shapes could be developed to perform semi-quantitative analysis of any point across the entirety of the image and provide information regarding the percentage of carbon atoms from the two different materials in the composite.
TechConnect World Technical Proceedings
Carbon Nanotubes, X-ray photoelectron spectroscopy, nanoEHS, composites, characterization