Dynamic properties of Span-80 adsorbed layers at paraffin-oil/water interface: Capillary pressure experiments under low gravity conditions

Pandolfini, P.; Loglio, G.; Ravera, Francesca; Liggieri, Libero; Kovalchuk, V. I.; Javadi, Aliyar; Karbaschi, Mohsen; Krägel, J.; Miller, R.; Noskov, Boris A.; Bykov, Alexey G.

doi:10.1016/j.colsurfa.2017.05.012

Cited by 8 publications

(24 citation statements)

References 38 publications

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“…The experiments were planned for different concentrations of Span-80 in paraffin-oil created via a series of injections of small surfactant amounts into the matrix liquid. However, as it was reported before in [20], a leakage has occurred from the injection syringe during the facility upload and installation on the ISS. As a consequence, the value of real Span-80 concentration in the majority of experiments was approximately within the range c = 2.0 × 10 −5 -3.0 × 10 −5 mol/dm 3 , as it has been estimated from the measured mean level of γ(t)-value (γ 0 = 23-26 mN/m) [20].…”

Section: Lucassen-van Den Tempel Modelmentioning

confidence: 59%

“…The composition of the studied couple of two-phase liquid systems was described in full details in [20,21].…”

Section: Methodsmentioning

confidence: 99%

“…A piezo-actuator, built in the measurement cell, allowed the harmonic oscillations of the drop interfacial area to be excited at 8 different frequencies (0.01, 0.02, 0.04, 0.08, 0.16, 0.32, 0.5, and 1.0 Hz), 3 different relative-area amplitudes (5%, 10%, and 20%), 3 different temperatures (first cell T = 20, 30, and 40 • C, second cell T = 15, 20, and 30 • C) and various different matrix concentrations. Telemetered data management, calibration and capillary-pressure measurement procedures were explicated in [20,21].…”

Section: Methodsmentioning

confidence: 99%

“…The interfacial dilational viscoelastic modulus, ε*(iω) is a physical quantity defined in the frequency domain by a complex expression [22]: The results for the first experimental system (i.e., Span-80 adsorbed at paraffin-oil/water interface) revealed the same trends: almost constant mean-level values of interfacial tension and an acceptable linearity range for the interfacial responses to area perturbations up to 20% amplitude (cf. Figures 13,14, and 17 in [20]).…”

Section: The Interfacial Dilational Viscoelastic Modulusmentioning

confidence: 96%

“…The first cell was dedicated to the study of the dynamic interfacial properties of a pure-water (spherical-cap shaped) drop, generated inside a Span-80/paraffin-oil matrix, while in the second cell a pure-hexane (spherical-cap shaped) drop was generated inside an aqueous C 13 DMPO/TTAB mixed solution matrix. Typical video frames of the drops inside the liquid matrices were, for example, visualized in Figure 4 of [20] and in Figure 1 of [21].…”

Section: Apparatusmentioning

confidence: 99%

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Interfacial Dilational Viscoelasticity of Adsorption Layers at the Hydrocarbon/Water Interface: The Fractional Maxwell Model

Loglio

Kovalchuk

Bykov

et al. 2019

Colloids and Interfaces

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In this communication, the single element version of the fractional Maxwell model (single-FMM or Scott–Blair model) is adopted to quantify the observed behavior of the linear interfacial dilational viscoelasticity. This mathematical tool is applied to the results obtained by capillary pressure experiments under low-gravity conditions aboard the International Space Station, for adsorption layers at the hydrocarbon/water interface. Two specific experimental sets of steady-state harmonic oscillations of interfacial area are reported, respectively: a drop of pure water into a Span-80 surfactant/paraffin-oil matrix and a pure n-hexane drop into a C13DMPO/TTAB mixed surfactants/aqueous-solution matrix. The fractional constitutive single-FMM is demonstrated to embrace the standard Maxwell model (MM) and the Lucassen–van-den-Tempel model (L–vdT), as particular cases. The single-FMM adequately fits the Span-80/paraffin-oil observed results, correctly predicting the frequency dependence of the complex viscoelastic modulus and the inherent phase-shift angle. In contrast, the single-FMM appears as a scarcely adequate tool to fit the observed behavior of the mixed-adsorption surfactants for the C13DMPO/TTAB/aqueous solution matrix (despite the single-FMM satisfactorily comparing to the phenomenology of the sole complex viscoelastic modulus). Further speculations are envisaged in order to devise combined FMM as rational guidance to interpret the properties and the interfacial structure of complex mixed surfactant adsorption systems.

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Section: Lucassen-van Den Tempel Modelmentioning

confidence: 59%

“…The composition of the studied couple of two-phase liquid systems was described in full details in [20,21].…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%