A systematic study on the effect of acidic, basic and neutral additives on dispersion of multiwalled carbon nanotubes using a dimethylformamide solution

Abstract

Presence of acidic, basic and neutral additives on dispersion of multiwalled carbon nanotubes (MWCNTs) in dimethylforamide (DMF) solution has been investigated. The surface charge measurement showed that MWCNTs in the presence of acidic additives in DMF exhibit a higher surface charge (-85 C g(-1)) than that with the basic additives (-22 C g(-1)). The stability of the MWCNTs dispersion was visually monitored and it was found that in the presence of acidic and no additives it would be stable and dispersed for more than five days, whereas MWCNTs suspension immediately settle down in the presence of basic and neutral additives. The degree of defects on MWCNTs was determined by analysis of detailed Raman spectra of as-received MWNCTs and MWNCTs dispersed in DMF with different additives. By exploring the correlation between the I-D/I-G (Raman analysis) ratio and the degree of defects, it was found that the carbon-carbon double bond (C=C) of MWCNTs was slightly damaged by adding additives to the solvent.