Novel parameter predicting stability of magnetic fluids for possible application in nanocomposite preparation

Лысенко, С. Н.; Астафьева, С. А.; Yakusheva, D. E.; Bǎlǎșoiu, M.

doi:10.1016/j.apsusc.2018.08.236

Cited by 9 publications

(10 citation statements)

References 33 publications

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“…For a colloid stabilized by oleic acid, a similar property was noted in refs , . At the same time, the weakly polar 1,4-dioxane (μ Dxn = 0.45 D, ε Dxn = 2.21) is an efficient precipitant for many fatty acid-capped colloids . These examples clearly demonstrate the aforementioned fact that the stability of a colloid is not determined only by the polar properties of the solvent.…”

Section: Results and Discussionsupporting

confidence: 74%

“…For example, for benzene, petroleum ether, and 1,4-dioxane the following values of S-factor were found before: 46, 104, and 20. 37 In the present study, they are 48.8, 102.8, and 20.7, respectively.…”

Section: ■ Results and Discussionmentioning

confidence: 46%

“…We note that the S -factor was proposed first in our paper where we considered the magnetic colloids stabilized by 7 different fatty acids and studied the coagulation effect in 15 mixtures composed of 3 solvents and 9 precipitantssee more details in the SI, Section VI. The S -factor was hypothesized to be equal for all surfactants used.…”

Section: Results and Discussionmentioning

confidence: 99%

“…Concluding the section, let us discuss the effect of surfactants on the S -factor. We mentioned already that in ref , the S -factor was assumed to be surfactant independent for all fatty acids used in experiments. Now, we can formulate the physical grounds of this hypothesis.…”

Section: Results and Discussionmentioning

confidence: 99%

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Osmotic Attraction: A New Mechanism of Nanoparticle Aggregation

et al. 2022

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Solvent-induced interactions of nanoparticles in colloidal solutions can substantially affect their physicochemical and transport properties. Predicting these interactions is challenging because the natural causes of the interactions are unclear. Here, we present a comprehensive experimental and theoretical study of the coagulation stability of the surfacted magnetic colloids. The magnetite nanoparticles stabilized by erucic acid were dispersed in 19 different good solvents. The colloidal stability was reduced by the gradual addition of a precipitant. As a precipitant, 19 other liquids were used. We show that coagulation is not associated with either dispersion or magnetic interactions. The coagulation mechanism is due to the osmotic attraction of nanoparticles induced by a specific local distribution of precipitant molecules. The precipitant molecules are repelled from the hydrophobic tails of the surfactant and form a depleted zone inside the surfactant layer leading to the appearance of the osmotic attraction between the nanoparticles and their subsequent coagulation when the critical concentration of the precipitant is reached. The quantitative description of the phenomenon is carried out within the framework of the generalized Asakura–Oosawa model of the attractive depletion forces between two adjacent particles and the Langmuir adsorption model for the equilibrium concentration of precipitant molecules in the surfactant layer of nanoparticles. The calculated precipitant critical concentrations, the coagulation curves of the polydisperse systems, and the variation of the coagulation criterion occurring upon changing the surfactant are in good agreement with the experimental data. The osmotic attraction mechanism is equally suitable for nanoparticles of any natureplasmonic, semiconductor, or magnetic. This is determined by the surfactant–solvent interactions and is generic for many solvent-mediated systems taken at arbitrary concentrations of precipitant.

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Section: Results and Discussionsupporting

confidence: 74%

Section: ■ Results and Discussionmentioning

confidence: 46%

Section: Results and Discussionmentioning

confidence: 99%

Section: Results and Discussionmentioning

confidence: 99%

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Osmotic Attraction: A New Mechanism of Nanoparticle Aggregation

et al. 2022

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“…An interesting case refers to the high stabilizing efficiency of the widely used oleic (unsaturated carboxylic) acid compared to saturated (stearic, palmitic, myristic and lauric) carboxylic acids, with less (myristic and lauric) or much less (stearic and palmitic) stabilizing effect. [132][133][134][135] In the case of non-polar ferrofluids with chemisorbed monolayer coated magnetite NPs, the excess non-adsorbed oleic acid or polymers alter the longterm colloidal stability. [136][137][138] To illustrate the meaning of "long-term colloidal stability", we refer to a sample of low vapor pressure oil-based sealing ferrofluid stabilized with oleic acid (saturation magnetization approx.…”

Section: Preparation Of Magnetic Fluidsmentioning

confidence: 99%