Interfacial shear rheology of asphaltenes at oil–water interface and its relation to emulsion stability: Influence of concentration, solvent aromaticity and nonionic surfactant

Yue, Fan; Simon, Sébastien; Sjöblom, Johan

doi:10.1016/j.colsurfa.2010.05.034

Cited by 212 publications

(209 citation statements)

References 43 publications

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“…31) In this study, the physical properties such as viscosity and surface tension of curcumin-loaded microemulsions were analyzed. The information may provide some clues to explain why the surfactant/water content affected the efficacy of curcumin dermal delivery.…”

Section: Resultsmentioning

confidence: 99%

Antimicrobial Activity of Curcumin-Loaded Myristic Acid Microemulsions against <i>Staphylococcus epidermidis</i>

Liu

Huang

2012

CHEMICAL & PHARMACEUTICAL BULLETIN

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The bactericidal properties of myristic acid and curcumin were revealed in a number of studies. However, whether curcumin-loaded myristic acid microemulsions can be used to inhibit Staphylococcus epidermidis, which causes nosocomial infections, has not been reported. Our aim was to develop curcumin-loaded myristic acid microemulsions to inhibit S. epidermidis on the skin. The interfacial tension, size distribution, and viscosity data of the microemulsions were characterized to elucidate the physicochemical properties of the curcumin microemulsions. Curcumin distribution in neonate pig skin was visualized using confocal laser scanning microscopy. Dermal curcumin accumulation (326 µg/g skin) and transdermal curcumin penetration (87 µg/cm 2 /d) were obtained with the microemulsions developed herein. Curcumin at the concentration of 0.86 µg/mL in the myristic acid microemulsion could inhibit 50% of the bacterial growth, which was 12 times more effective than curcumin dissolved in dimethyl sulfoxide (DMSO). The cocktail combination of myristic acid and curcumin in the microemulsion carrier synergistically inhibited the growth of S. epidermidis. The results we obtained highlight the potential of using curcumin-loaded microemulsions as an alternative treatment for S. epidermidis-associated diseases and acne vulgaris.

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Section: Resultsmentioning

confidence: 99%

Antimicrobial Activity of Curcumin-Loaded Myristic Acid Microemulsions against <i>Staphylococcus epidermidis</i>

Liu

Huang

2012

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…Fan and co-workers 22 used the same bicone technique to study film aging kinetics of asphaltenes dispersed in toluene-heptane (6:4) solution. After 20 hr of aging, the frequency dependent rheological properties of the interfacial film indicated the formation of a consolidated network, with both the viscous and elastic response of the film exhibiting a small dependency on oscillation frequency.…”

Section: Introductionmentioning

confidence: 99%

Problematic Stabilizing Films in Petroleum Emulsions: Shear Rheological Response of Viscoelastic Asphaltene Films and the Effect on Drop Coalescence

et al. 2014

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Adsorption of asphaltenes at the water-oil interface contributes to the stability of petroleum emulsions by forming a networked film that can hinder drop-drop coalescence. The interfacial microstructure can either be liquid-like or solid-like, depending on: i) initial bulk concentration of asphaltenes, ii) interfacial aging time, and iii) solvent aromaticity. Two techniques: interfacial shear rheology and integrated thin film drainage apparatus provided equivalent interface aging conditions, enabling direct correlation of the interfacial rheology and droplet stability. The shear rheological properties of the asphaltene film were found to be critical to the stability of contacting droplets. With a viscous dominant interfacial microstructure, the coalescence time for two drops in intimate contact was rapid, on the order of seconds. However, as the elastic contribution develops and the film microstructure begins to be dominated by elasticity, the two drops in contact do not coalescence. Such step-change transition in coalescence is thought to be related to the high shear yield stress (~10 4 Pa), which is a function of the film shear yield point and the film thickness (as measured by quartz crystal microbalance), and the increased elastic stiffness of the film that prevents mobility and rupture of the asphaltene film which when in a solid-like state provides an energy barrier for the droplets to coalescence.

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“…In simple shear experiments, flow is induced at a constant area, while in dilation the area of the interface is changed. Studies on interfacial shear rheology 14,15 using a biconical geometry showed that asphaltenes form films of high elasticity after several hours of aging. Furthermore, a concentration threshold range of 2-5 g/L was found for the formation of the mechanically strong film at the oil/water interface after aging.…”

Section: Introductionmentioning

confidence: 99%

Sorption and Interfacial Rheology Study of Model Asphaltene Compounds

et al. 2016

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The sorption and rheological properties of an acidic polyaromatic compound (C5PeC11), which can be used to further our understanding in the behavior of asphaltenes, are determined experimentally. The results show that C5PeC11 exhibits the type of pH-dependent surface activity and interfacial shear rheology observed in C6-asphaltenes with a decrease in the interfacial tension concomitant to the elastic modulus when the pH increases. Surface pressure-area (Π-A) isotherms show evidence of aggregation behavior and π-π stacking at both the air/water and oil/water interfaces. Similarly, interactions between adsorbed C5PeC11 compounds are evidenced through desorption experiments at the oil/water interface. Contrary to indigenous asphaltenes, adsorption is reversible, but desorption is slower than for noninteracting species. The reversibility enables us to create layers reproducibly, whereas the presence of interactions between the compounds enables us to mimic the key aspects of interfacial activity in asphaltenes. Shear and dilatational rheology show that C5PeC11 forms a predominantly elastic film both at the liquid/air and the liquid/liquid interface. Furthermore, a soft glassy rheology model (SGR) fits the data obtained at the liquid/liquid interface. Yet, it is shown that the effective noise temperature determined from the SGR model for C5PeC11 is higher than for indigenous asphaltenes measured under similar conditions. Finally, from a colloidal and rheological standpoint, the results highlight the importance of adequately addressing the distinction between the material functions and true elasticity extracted from a shear measurement and the apparent elasticity measured in dilatational-pendant drop set-ups.

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Interfacial shear rheology of asphaltenes at oil–water interface and its relation to emulsion stability: Influence of concentration, solvent aromaticity and nonionic surfactant

Cited by 212 publications

References 43 publications

Antimicrobial Activity of Curcumin-Loaded Myristic Acid Microemulsions against <i>Staphylococcus epidermidis</i>

Antimicrobial Activity of Curcumin-Loaded Myristic Acid Microemulsions against <i>Staphylococcus epidermidis</i>

Problematic Stabilizing Films in Petroleum Emulsions: Shear Rheological Response of Viscoelastic Asphaltene Films and the Effect on Drop Coalescence

Sorption and Interfacial Rheology Study of Model Asphaltene Compounds

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