Colloids and Interfaces

22 pages, 2853 KiB

Open AccessReview

The Oscillatory Spinning Drop Technique. An Innovative Method to Measure Dilational Interfacial Rheological Properties of Brine-Crude Oil Systems in the Presence of Asphaltenes

by Ronald Marquez, Johnny Bullon, Ana Forgiarini and Jean-Louis Salager

Colloids Interfaces 2021, 5(3), 42; https://doi.org/10.3390/colloids5030042 - 04 Aug 2021

Cited by 8 | Viewed by 4895

Abstract

The oscillatory spinning drop method has been proven recently to be an accurate technique to measure dilational interfacial rheological properties. It is the only available equipment for measuring dilational moduli in low interfacial tension systems, as it is the case in applications dealing [...] Read more.

The oscillatory spinning drop method has been proven recently to be an accurate technique to measure dilational interfacial rheological properties. It is the only available equipment for measuring dilational moduli in low interfacial tension systems, as it is the case in applications dealing with surfactant-oil-water three-phase behavior like enhanced oil recovery, crude oil dehydration, or extreme microemulsion solubilization. Different systems can be studied, bubble-in-liquid, oil-in-water, microemulsion-in-water, oil-in-microemulsion, and systems with the presence of complex natural surfactants like asphaltene aggregates or particles. The technique allows studying the characteristics and properties of water/oil interfaces, particularly when the oil contains asphaltenes and when surfactants are present. In this work, we present a review of the measurements of crude oil-brine interfaces with the oscillating spinning drop technique. The review is divided into four sections. First, an introduction on the oscillating spinning drop technique, fundamental and applied concepts are presented. The three sections that follow are divided according to the complexity of the systems measured with the oscillating spinning drop, starting with simple surfactant-oil-water systems. Then the complexity increases, presenting interfacial rheology properties of crude oil-brine systems, and finally, more complex surfactant-crude oil-brine systems are reviewed. We have found that using the oscillating spinning drop method to measure interfacial rheology properties can help make precise measurements in a reasonable amount of time. This is of significance when systems with long equilibration times, e.g., asphaltene or high molecular weight surfactant-containing systems are measured, or with systems formulated with a demulsifier which is generally associated with low interfacial tension. Full article

(This article belongs to the Special Issue Interfacial Dynamics)

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13 pages, 2664 KiB

Open AccessArticle

Mathematical Modeling of Water-Soluble Astaxanthin Release from Binary Polysaccharide/Gelatin Blend Matrices

by Katarzyna Łupina, Dariusz Kowalczyk, Tomasz Skrzypek and Barbara Baraniak

Colloids Interfaces 2021, 5(3), 41; https://doi.org/10.3390/colloids5030041 - 03 Aug 2021

Cited by 1 | Viewed by 2933

Abstract

Water-soluble AstaSana astaxanthin (AST) was loaded into 75/25 blend films made of polysaccharides (carboxymethyl cellulose (CMC), gum Arabic (GAR), starch sodium octenyl succinate (OSA), water-soluble soy polysaccharides (WSSP)) and gelatin (GEL) at levels of 0.25, 0.5, and 1%, respectively. Due to the presence [...] Read more.

Water-soluble AstaSana astaxanthin (AST) was loaded into 75/25 blend films made of polysaccharides (carboxymethyl cellulose (CMC), gum Arabic (GAR), starch sodium octenyl succinate (OSA), water-soluble soy polysaccharides (WSSP)) and gelatin (GEL) at levels of 0.25, 0.5, and 1%, respectively. Due to the presence of starch granules in the AST formulation, the supplemented films exhibited increased surface roughness as compared to the AST-free films. Apart from the CMC/GEL carrier, the migration of AST to water (25 °C, 32 h) was incomplete. Excluding the CMC-based carrier, the gradual rise in the AST concentration decreased the release rate. The Hopfenberg with time lag model provided the best fit for all release series data. Based on the quarter-release times (t_25%), the 0.25% AST-supplemented OSA/GEL film (t_25% = 13.34 h) ensured a 1.9, 2.2, and 148.2 slower release compared to the GAR-, WSSP- and CMC-based carriers, respectively. According to the Korsmeyer–Peppas model, the CMC-based films offered a quasi-Fickian release of AST (n < 0.5) with the burst effect (t_100% = 0.5–1 h). In general, the release of AST from the other films was multi-mechanistic (n > 0.5), i.e., controlled at least by Fickian diffusion and the polymer relaxation (erosion) mechanism. The 1% AST-added WSSP/GEL system provided the most linear release profile. Full article

(This article belongs to the Special Issue Interfacial Phenomena)

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21 pages, 7080 KiB

Open AccessArticle

Effect of Surfactant Dynamics on Flow Patterns Inside Drops Moving in Rectangular Microfluidic Channels

by Nina M. Kovalchuk and Mark J. H. Simmons

Colloids Interfaces 2021, 5(3), 40; https://doi.org/10.3390/colloids5030040 - 02 Aug 2021

Cited by 6 | Viewed by 3540

Abstract

Drops contained in an immiscible liquid phase are attractive as microreactors, enabling sound statistical analysis of reactions performed on ensembles of samples in a microfluidic device. Many applications have specific requirements for the values of local shear stress inside the drops and, thus, [...] Read more.

Drops contained in an immiscible liquid phase are attractive as microreactors, enabling sound statistical analysis of reactions performed on ensembles of samples in a microfluidic device. Many applications have specific requirements for the values of local shear stress inside the drops and, thus, knowledge of the flow field is required. This is complicated in commonly used rectangular channels by the flow of the continuous phase in the corners, which also affects the flow inside the drops. In addition, a number of chemical species are present inside the drops, of which some may be surface-active. This work presents a novel experimental study of the flow fields of drops moving in a rectangular microfluidic channel when a surfactant is added to the dispersed phase. Four surfactants with different surface activities are used. Flow fields are measured using Ghost Particle Velocimetry, carried out at different channel depths to account for the 3-D flow structure. It is shown that the effect of the surfactant depends on the characteristic adsorption time. For fast-equilibrating surfactants with a characteristic time scale of adsorption that is much smaller than the characteristic time of surface deformation, this effect is related only to the decrease in interfacial tension, and can be accounted for by the change in capillary number. For slowly equilibrating surfactants, Marangoni stresses accelerate the corner flow, which changes the flow patterns inside the drop considerably. Full article

(This article belongs to the Special Issue Interfacial Dynamics)

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15 pages, 2574 KiB

Open AccessArticle

A Multistate Adsorption Model for the Adsorption of C₁₄EO₄ and C₁₄EO₈ at the Solution/Air Interface

by Valentin B. Fainerman, Volodymyr I. Kovalchuk, Eugene V. Aksenenko, Francesca Ravera, Libero Liggieri, Giuseppe Loglio, Alexander V. Makievski, Natalia O. Mishchuk, Emanuel Schneck and Reinhard Miller

Colloids Interfaces 2021, 5(3), 39; https://doi.org/10.3390/colloids5030039 - 29 Jul 2021

Cited by 8 | Viewed by 2345

Abstract

The dynamic and equilibrium properties of adsorption layers of poly (oxyethylene) alkyl ether (C_nEO_m) can be well described by the reorientation model. In its classical version, it assumes two adsorption states; however, there are obviously surfactants that can adsorb [...] Read more.

The dynamic and equilibrium properties of adsorption layers of poly (oxyethylene) alkyl ether (C_nEO_m) can be well described by the reorientation model. In its classical version, it assumes two adsorption states; however, there are obviously surfactants that can adsorb in more than two possible conformations. The experimental data for C₁₄EO₄ and C₁₄EO₈ (dynamic and equilibrium surface tensions and surface dilational visco-elasticity as measured by bubble profile analysis tensiometry) are used to verify if a reorientation model with more than two possible adsorption states can better describe the complete set data of C_nEO_m adsorption layers at the water/air interface. The proposed refined theoretical model allows s different states of the adsorbing molecules at the interface. The comparison between the model and experiment demonstrates that, for C₁₄EO₄, the assumption of s = 5 adsorption states provides a much better agreement than for s = 2, while for C₁₄EO₈, a number of s = 10 adsorption states allows an optimum data description. Full article

(This article belongs to the Special Issue Interfacial Dynamics)

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17 pages, 2307 KiB

Open AccessArticle

Ion-Specific and Solvent Effects on PDADMA–PSS Complexation and Multilayer Formation

by Jasmina Jukić, Karla Korade, Ana-Marija Milisav, Ida Delač Marion and Davor Kovačević

Colloids Interfaces 2021, 5(3), 38; https://doi.org/10.3390/colloids5030038 - 21 Jul 2021

Cited by 9 | Viewed by 3418

Abstract

Among various parameters that influence the formation of polyelectrolyte complexes and multilayers, special emphasis should be placed on ion-specific and solvent effects. In our study, we systematically examined the above-mentioned effects on poly(diallyldimethylammonium chloride) (PDADMACl)-sodium poly(4-styrenesulfonate) (NaPSS) complexation in solution and at the [...] Read more.

Among various parameters that influence the formation of polyelectrolyte complexes and multilayers, special emphasis should be placed on ion-specific and solvent effects. In our study, we systematically examined the above-mentioned effects on poly(diallyldimethylammonium chloride) (PDADMACl)-sodium poly(4-styrenesulfonate) (NaPSS) complexation in solution and at the surface by means of dynamic light scattering, ellipsometry and atomic force microscopy measurements. As solvents, we used water and water/ethanol mixture. The obtained results confirm the importance of ion-specific and solvent effects on complexes prepared in solution, as well as on multilayers built up on a silica surface. The experiments in mixed solvent solution showed that at a higher ethanol mole fraction, the decrease in monomer titrant to titrand ratio, at which the increase in the size of complexes is observed, takes place. The difference between chloride and bromide ions was more pronounced at a higher mole fraction of ethanol and in the case of positive complex formation, suggesting that the larger amount of bromide ions could be condensed to the polycation chain. These findings are in accordance with the results we obtained for polyelectrolyte multilayers and could be helpful for designing polyelectrolyte multilayers with tuned properties needed for various applications, primarily in the field of biomedicine. Full article

(This article belongs to the Special Issue Interfacial Dynamics)

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19 pages, 6622 KiB

Open AccessArticle

A pH-Responsive Foam Formulated with PAA/Gemini 12-2-12 Complexes

by Hernán Martinelli, Claudia Domínguez, Marcos Fernández Leyes, Sergio Moya and Hernán Ritacco

Colloids Interfaces 2021, 5(3), 37; https://doi.org/10.3390/colloids5030037 - 19 Jul 2021

Cited by 6 | Viewed by 3092

Abstract

In the search for responsive complexes with potential applications in the formulation of smart dispersed systems such as foams, we hypothesized that a pH-responsive system could be formulated with polyacrylic acid (PAA) mixed with a cationic surfactant, Gemini 12-2-12 (G12). We studied PAA-G12 [...] Read more.

In the search for responsive complexes with potential applications in the formulation of smart dispersed systems such as foams, we hypothesized that a pH-responsive system could be formulated with polyacrylic acid (PAA) mixed with a cationic surfactant, Gemini 12-2-12 (G12). We studied PAA-G12 complexes at liquid–air interfaces by equilibrium and dynamic surface tension, surface rheology, and X-ray reflectometry (XRR). We found that complexes adsorb at the interfaces synergistically, lowering the equilibrium surface tension at surfactant concentrations well below the critical micelle concentration (cmc) of the surfactant. We studied the stability of foams formulated with the complexes as a function of pH. The foams respond reversibly to pH changes: at pH 3.5, they are very stable; at pH > 6, the complexes do not form foams at all. The data presented here demonstrate that foam formation and its pH responsiveness are due to interfacial dynamics. Full article

(This article belongs to the Special Issue Interfacial Phenomena)

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7 pages, 1450 KiB

Open AccessArticle

Electrohydrodynamic Instabilities in Free Emulsion Films

by Farshid Mostowfi, Plamen Tchoukov, Nikolay Panchev, Tadeusz Dabros and Jan Czarnecki

Colloids Interfaces 2021, 5(3), 36; https://doi.org/10.3390/colloids5030036 - 01 Jul 2021

Viewed by 2580

Abstract

Electrohydrodynamic instabilities were induced in thin water-in-oil emulsion films by application of external DC electric field. The dominant wavelengths of instabilities were measured for constant electric fields of various strengths. The dominant wavelengths agreed reasonably well with theoretical predictions based on a linear [...] Read more.

Electrohydrodynamic instabilities were induced in thin water-in-oil emulsion films by application of external DC electric field. The dominant wavelengths of instabilities were measured for constant electric fields of various strengths. The dominant wavelengths agreed reasonably well with theoretical predictions based on a linear stability model. The linear stability model used in this study took into account experimentally measured repulsive disjoining pressure and calculated Maxwell stress. The observation of such instabilities can help to understand the rupture mechanism of emulsion films under the influence of electric field. Full article

(This article belongs to the Special Issue Heterogeneous Interfacial Layers – Implications in Thin Liquid Films and Soft Colloids (Dedicated to the 65th Anniversary of Prof. Elena Mileva))

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16 pages, 16412 KiB

Open AccessReview

Effect of Produced Sand Particles and Fines on Scale Inhibitor: A Review

by Uche C. Anyanwu and Gbenga F. Oluyemi

Colloids Interfaces 2021, 5(3), 35; https://doi.org/10.3390/colloids5030035 - 23 Jun 2021

Cited by 2 | Viewed by 3475

Abstract

Application of scale inhibitors in oil and gas production is aimed at mitigating scale blockage during production. Many experimental, mathematical, and numerical simulation modeling works have been carried out to evaluate behavior, performance, and interaction of the scale inhibitor chemicals within porous media [...] Read more.

Application of scale inhibitors in oil and gas production is aimed at mitigating scale blockage during production. Many experimental, mathematical, and numerical simulation modeling works have been carried out to evaluate behavior, performance, and interaction of the scale inhibitor chemicals within porous media in relation to their efficiency in solving scale problem. However, the mechanisms underpinning scale inhibitors performance are not well published. Some research works have shown theoretically that not all scale inhibitors pumped into the formation adsorb onto the formation rock. Some of the inhibitors may adsorb on produced loose sand grains or colloidal fine sand particles which float and flow within the pore spaces along with the scale inhibitor mostly in unconsolidated reservoirs This paper provides a review of research work on the effect of produced loose sand or colloidal fine particles flow on polyphosphonates and polyphosphinopolymer scale inhibitors performances during crude production. Full article

(This article belongs to the Special Issue Locomotion of Colloidal Particles)

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Colloids Interfaces, Volume 5, Issue 3 (September 2021) – 8 articles

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