Surfactant concentration and pH effects on the zeta potential values of alumina nanofluids to inspect stability

Cacua, Karen; Ordóñez, Fredy; Zapata, Camilo; Herrera, Bernardo; Pabón, Elizabeth; Buitrago‐Sierra, Robison

doi:10.1016/j.colsurfa.2019.123960

Cited by 197 publications

(69 citation statements)

References 45 publications

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Section: Resultsmentioning

confidence: 99%

“…As can be seen, the value of Z avg for all samples were significantly larger than the actual size of MWCNTs and this is due to the fact that any particles in a solution will experience increase in their hydrodynamic size resulted from the formation of hydration layer as well as layer produced by interaction of the particles with surrounding ions present in the solution. [32] The dispersion containing pristine MWCNTs exhibited the highest Z avg of 697.6 ± 1643 nm and extremely broad particle size distribution with PDI of 0.764. These results were in agreement with its recorded ζ-potential, showing high degree of instability of the system.…”

Section: Zeta Potential and Dls Measurement For Surfactant Dispersibilitymentioning

confidence: 93%

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Performance Enhancement of Inkjet Printed Multi‐Walled Carbon Nanotubes Inks using Synthetic and Green Surfactants

Kamarudin

Jaafar

Manaf³

et al. 2021

Adv Materials Technologies

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While the efficiency of synthetic surfactants in controlling the dispersion behaviour of nanomaterials in aqueous solution has been well documented, issues on environmental impact remain unsolved. The aim of this study is to synthesize multi‐walled carbon nanotubes (MWCNTs) inks using green surfactants and their chemical, physical, and electrical performances are compared to those of synthetic surfactant inks. The conductive ink is synthesized by dispersing MWCNTs in surfactant solution (gum Arabic [GA], alkali lignin [AL], polyvinylpyrrolidone [PVP] or pluronic F‐127 [PL]) with various concentrations. Among four investigated surfactants, GA/MWCNTs and PVP/MWCNTs inks are selected for further investigation due to their excellent dispersion stability. The printability of both inks is assessed by analyzing the quality of the conductive patterns printed with different inkjet printers theoretically and experimentally. It is found that multi‐nozzle printer is capable of developing printed patterns with lower sheet resistance compared to single‐nozzle printer. Overall, 5 GA/MWCNTs ink recorded as the most stable ink with only 14.4% reduction of absorbance after 30 days and with zeta potential value of −40.3 ± 5.36 mV. Ten layers of 5 GA/MWCNTs ink printed on PVA demonstrate a dense MWCNTs networks, which contribute to the lowest surface resistance of 3.0 kΩ sq−1.

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Section: Resultsmentioning

confidence: 99%

Section: Zeta Potential and Dls Measurement For Surfactant Dispersibilitymentioning

confidence: 93%

Performance Enhancement of Inkjet Printed Multi‐Walled Carbon Nanotubes Inks using Synthetic and Green Surfactants

Kamarudin

Jaafar

Manaf³

et al. 2021

Adv Materials Technologies

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“…Unstable nanofluids will exhibit a major decrease in initial absorbance value due to sedimentation of agglomerates. [18][19][20][21] To evaluate their efficacy for heat transfer applications, the thermal conductivity of RGO/Fe 3 O 4 nanofluids were studied as a function of volume fraction. To take into consideration the contribution of surfactant on nanofluid k, the thermal con- ductivity measurement was done for base fluid containing SDBS and the result shows no apparent change in base fluid k in presence of SDBS.…”

Section: Resultsmentioning

confidence: 99%

Novel Nanohybrid Containing Magnetite Nanocluster‐Decorated Reduced Graphene Oxide Nanosheets for Heat Transfer Applications

Damodaran

2021

ChemistrySelect

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A novel nanohybrid comprised of magnetite (Fe 3 O 4 ) nanocluster-decorated reduced graphene oxide (RGO) nanosheets and its dispersions (nanofluids) were developed for heat transfer applications. The RGO/Fe 3 O 4 nanohybrid was synthesized by a facile and cost-effective one-pot solvothermal route. The morphological, structural, chemical, and magnetic features of RGO/Fe 3 O 4 nanohybrid was characterized by using various analysis techniques. To evaluate the efficacy of as-synthesized nanohybrid for thermal engineering applications, stable water -based RGO/Fe 3 O 4 nanofluids were synthesized and their thermal conductivity (k) was measured as a function of volume fraction (ϕ). Maximum 18 % enhancement in k value was attained for RGO/Fe 3 O 4 nanofluids even at a low nanohybrid concentration of ϕ = 0.026. The synergistic effects of RGO (large surface area, high inherent k, hydrophilic nature, and relatively low density) and Fe 3 O 4 (efficient conduction paths through zero-field dipolar structures) components provided excellent stability and enhanced thermal conductivity to RGO/Fe 3 O 4 nanofluids in the present study. The results demonstrate that RGO/Fe 3 O 4 nanohybrid is a promising nanoadditive in designing efficient nanofluids for heat transport applications.

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“…Dib et al [11], reported that the presence of NPs enhances heat transfer for their problem of setting the flow between two plates. Cacua et al [12], demonstrated that NPs improve the thermal characteristics. In practice, NFs might have severe stability issues due to the agglomeration and sedimentation of NPs with time, which limits the applicability of the NFs.…”

Section: Introductionmentioning

confidence: 99%

“…To cover the stability issue, Cacua. et al [12] added surfactants for producing electrostatic or steric repulsion between NPs. Choudhary et al [13] presented the stability analysis of a (Al 2 O 3 )/water NF.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Thermally Developed Pulsatile Flow of a Hybrid Nanofluid in a Constricted Channel

et al. 2021

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Heat transfer analysis of the pulsatile flow of a hybrid nanofluid through a constricted channel under the impact of a magnetic field and thermal radiation is presented. Hybrid nanofluids form a new class of nanofluids, distinguished by the thermal properties and functional utilities for improving the heat transfer rate. The behaviors of a water-based copper nanofluid and water-based copper plus a single-wall carbon nanotube, i.e., (Cu–SWCNT/water), hybrid nanofluid over each of velocity, wall shear stress, and temperature profiles, are visualized graphically. The time-dependent governing equations of the incompressible fluid flow are transformed to the vorticity-stream function formulation and solved numerically using the finite difference method. The laminar flow simulations are carried out in 2D for simplicity as the flow profiles are assumed to vary only in the 2D plane represented by the 2D Cartesian geometry. The streamlines and vorticity contours are also shown to demonstrate the flow behviour along the channel. For comparison of the flow characteristics and heat transfer rate, the impacts of variations in Hartmann number, Strouhal number, Prandtl number, and the thermal radiation parameter are analyzed. The effects of the emerging parameters on the skin friction coefficient and Nusselt number are also examined. The hybrid nanofluid is demonstrated to have better thermal characteristics than the traditional one.

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Surfactant concentration and pH effects on the zeta potential values of alumina nanofluids to inspect stability

Cited by 197 publications

References 45 publications

Performance Enhancement of Inkjet Printed Multi‐Walled Carbon Nanotubes Inks using Synthetic and Green Surfactants

Performance Enhancement of Inkjet Printed Multi‐Walled Carbon Nanotubes Inks using Synthetic and Green Surfactants

Novel Nanohybrid Containing Magnetite Nanocluster‐Decorated Reduced Graphene Oxide Nanosheets for Heat Transfer Applications

Numerical Simulation of the Thermally Developed Pulsatile Flow of a Hybrid Nanofluid in a Constricted Channel

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