Re-dispersion ability of multi wall carbon nanotubes within low viscous mineral oil

Abstract

The main purpose of this study is to focus the light for the first time on the recognized re-dispersion ability of the sonicated MWCNTs within low viscous mineral oil. For that, pure MWCNTs, without any special treatment, were dispersed in mineral oil by sonication without using any stabilization method. After full agglomeration, it was realized that agitating, shaking or even blowing compressed air on the agglomerated nanolubricant is able to break down the aggregation of the MWCNTs. Microscopic video is presented to clarify the behavior of the tubes during the re-dispersion process. Quantitatively, particle size distribution (PSD) was employed to evaluate the re-dispersion quality. The viscosity and thermal conductivity of both recently sonicated and re-dispersed samples were also investigated with accurate measurement setups at four different weight concentrations (0.05, 0.1, 0.2 and 0.3 wt.%). It was observed that the sonicated MWCNTs are separated, saturated, lubricated, and surrounded by oil layers, which not only ease its motion within the lubrication oil, but also give them the ability of detaching by applying any slight force. Moreover, the PSD results with the equal values of the viscosity and thermal conductivity, obtained within the uncertainty of the measurements, confirm that the MWCNTs were re-dispersed to the same quality of the recently sonicated ones by just shaking.