Xinfang Li

Influence of SDBS on Stability of Copper Nano-Suspensions

Dispersion and stability of Cu nano-suspensions with dispersant is the important base for the study of rheology and heat transfer enhancement of the suspensions. This paper presented a procedure for preparing a nanofluid which was a suspension consisting of nanophase powders and a base liquids. By means of the procedure, Cu-H2 O nanofluids with and without dispersant were prepared, whose sedimentation photographs were given to illustrate the stability and evenness of suspension with dispersant. Dispersion and stability of Cu nanoparticles in water were studied under different pH values and the concentration of sodium dodecylbenzenesulfonate (SDBS) dispersant by the method of zeta potential, absorbency and sedimentation photographs. The results show that zeta potential has very corresponding relation with absorbency, and the higher absolute value of zeta potential and absorbency are, the better dispersion and stability in system is. The absolute value of zeta potential and absorbency are higher at pH 9.5. SDBS can significantly increase the absolute value of the zeta potential of the particle surfaces by electrostatic repulsions, which leads to the enhancement of the stability of the Cu suspensions. The optimizing concentration for SDBS in the 0.1% copper nano-suspensions is 0.07%, which has the best disperse results.Copyright

Influence of CATB on Stability of Copper Nano-Suspensions

Dispersion and stability of Cu nano-suspensions with dispersant is the important base for the study of rheology and heat transfer enhancement of the suspensions. This paper presented a procedure for preparing a nanofluid which was a suspension consisting of nanophase powders and a base liquids. By means of the procedure, Cu-H2O nanofluids with and without dispersant were prepared, whose sedimentation photographs were given to illustrate the stability and evenness of suspension with dispersant. Dispersion and stability of Cu nanoparticles in water were studied under different pH values and the concentration of hexadecyl trimethyl ammonium bromide (CATB) dispersant by the method of zeta potential and absorbency. The results show that zeta potential has very corresponding relation with absorbency, and the higher absolute value of zeta potential and absorbency are, the better dispersion and stability in system is. The absolute value of zeta potential is higher at pH 9.5. CATB can significantly increase the absolute value of the zeta potential of the particle surfaces by electrostatic repulsions, which leads to the enhancement of the stability of the Cu suspensions. The optimizing concentration for CATB in the 0.1% copper nano-suspensions is 0.05%, which has the best disperse results.

Surface Modification of Nano-Copper and its Dispersive Behavior in Water

In this paper, by measurement of zeta potential and particle size the surface modification of Cu nanoparticles in water was investigated at different pH values and different concentration of sodium dodecylbenzenesulfonate (SDBS) dispersant. The results show that the absolute value of zeta potential has very corresponding relation with particle size, and that the higher the absolute value of zeta potential and the smaller of the particle size are, the better dispersion and stability of copper nano-suspensions system is. It is also found that SDBS can significantly affect the value of zeta potential and particle size by electrostatic repulsions, which lead to the enhancement of the stability of the Cu suspensions, and the optimizing concentration for SDBS in 0.1% copper nano-suspensions is 0.07%, which have the best disperse results.

Effect of pH and Chemical Surfactant on Thermal Conductivity Enhancement of Cu-H2O Nanofluids

Nanofluids have been attractive for the last few years with the enormous potential to improve the efficiency of heat transfer fluids. This work focuses on the effect of pH and sodium dodecylbenzenesulfonate (SDBS) surfactant on the thermal conductivity of nanofluids.The thermal conductivity was measured by a Hot Disk Thermal Constants Anlyser. The results showed that the thermal conductivity enhancements of Cu–H2 O nanofluids are highly dependent on the weight fraction of nanoparticle, pH values and SDBS surfactant concentration of nano-suspensions. The Cu–H2 O nanofluids with an ounce of Cu have noticeably higher thermal conductivity than the base fluid without nanoparticles, For Cu nanoparticles at a weight fraction of 0.001 (0.1 wt %), thermal conductivity was enhanced by up to 10.7%, with an optimal pH value and SDBS concentration for the highest thermal conductivity. Therefore, the combined treatment with both the pH and chemical surfactant is recommended to improve the thermal conductivity for practical applications of nanofluid.Copyright

Influence of SDBS on stability of Al2O3 nano-suspensions

In this paper, the stability of Al2O3 nano-particles in water were investigated at different pH values and different concentration of sodium dodecylbenzenesulfonate (SDBS) dispersant by measurement of the zeta potential and absorbency. The experimental results show that zeta potential is relation with absorbency, and the higher magnitude of zeta potential corresponds to the higher absorbency, and the better dispersion and good stability of the Al2O3-H2O nano-suspensions. It is also found that the concentration of SDBS can significantly affect the value of zeta potential and absorbency. The experimental results show that for SDBS there is an optimizing concentration in the nanofluids which can induce high zeta potential and high absorbency, and that in 0.1% Al2O3 -H2O nano-suspensions the optimizing concentration of SDBS is 0.09%, which has the best disperse results of the nanofluids.