Since carbon nanotubes (CNT) are unstable in such polar solvents as water, using surfactants may overcome this challenge to a great extent by creating non-covalent bonds. In the present work, we experimentally studied the stability and thermophysical properties of different surfactants including gum Arabic (GA), cetyl trimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) in aqueous suspension of multi walled carbon nanotubes (MWCNT). To this end, aqueous suspension of surfactant-MWCNT was synthesized in the ratios 0.5-1, 1-1 and 2-1. Regarding stability, zeta potential was used to determine stability of abovementioned suspensions. Dynamic light scattering (DLS) analysis was also used to determine particles size distribution. The results indicated relative stability of suspensions in all ratios. It was also found that the minimum particle size was for the ratio 1-1 for the surfactants SDS and CTAB. Thermophysical properties of abovementioned suspensions including viscosity, shear stress, electrical conductivity, surface tension and density were also studied at 20-80°C. The results indicated an increase in electrical conductivity, density, viscosity, shear stress and a decrease in surface tension (except in GA) of suspensions in all concentrations relative to pure water in constant temperature. As temperature increases, electrical conductivity increases too and viscosity, shear stress, density and surface tension decreases or are constant for all concentrations.

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