Partial coalescence of droplets at oil–water interface subjected to different electric waveforms: Effects of non-ionic surfactant on critical electric field strength

Yang, Donghai; Sun, Yongxiang; He, Limin; Luo, Xiaoming; Lü, Yuling; Gao, Qifeng

doi:10.1016/j.cherd.2018.12.019

Cited by 17 publications

(12 citation statements)

References 38 publications

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“…In the experimental studies, the radii of droplets were generally in the range of 0.3–0.6 mm. 15,49,50 That is, the droplet sizes used in MD simulations are about five orders of magnitude smaller than those used in the experiments. This is because current computing power is not yet capable of performing MD calculations for the enormous number of water molecules in actual droplets.…”

Section: Resultsmentioning

confidence: 96%

Effect of electric field on coalescence of an oil-in-water emulsion stabilized by surfactant: a molecular dynamics study

Wang

Zhang

et al. 2022

RSC Adv.

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Section: Resultsmentioning

confidence: 96%

Effect of electric field on coalescence of an oil-in-water emulsion stabilized by surfactant: a molecular dynamics study

Wang

Zhang

et al. 2022

RSC Adv.

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“…So, the radii of droplets 1 and 2 are about 2.65 and 2.25 nm, respectively, which is comparable to the droplet sizes in other similar MD simulations. The droplet sizes can influence the critical field strength of electrocoalescence and the coalescence behaviors of droplets, such as migration speed, merging rate, and contact cone angle. , In the experimental studies, ,,, the radii of droplets are generally in the range of 0.3–0.6 mm. That is, the droplet sizes used in MD simulations are about 5 orders of magnitude smaller than those used in the experiments.…”

Section: Resultsmentioning

confidence: 99%

“…Some researchers have investigated experimentally the coalescence of droplets in emulsions in the presence of surfactants under external electric fields. ,− Mousavichoubeh et al investigated the effects of interfacial tension, which is manipulated by using different surfactants (anionic and nonionic), on secondary drop formation in electrocoalescence of water droplets in oil. The results indicate that interfacial tension is one of the main factors affecting the formation of secondary droplets, which is responsible for the partial coalescence.…”

Section: Introductionmentioning

confidence: 99%

“…They found that the presence of the surfactant affects both the extent of deformation and the modes of breakup. Yang et al 40 investigated the effects of surfactants on the partial coalescence of droplets at oil−water interface employing sunflower oil and nonionic surfactant solutions under different electric fields. It is suggested that surfactants can adsorb to the oil−water interface to reduce the interfacial tension, increasing the deformability of the coalescing droplet.…”

Section: ■ Introductionmentioning

confidence: 99%

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Molecular Dynamics Study on the Demulsification Mechanism of Water-In-Oil Emulsion with SDS Surfactant under a DC Electric Field

Yuan

Zhang

et al. 2022

Langmuir

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Application of an electric field is an effective demulsification method for water-in-oil (W/O) emulsions. For the W/O emulsions stabilized by anionic surfactants, the microscopic demulsification mechanism is still not very clear. In this work, the coalescence behavior of two droplets stabilized by the anionic surfactant sodium dodecyl sulfate (SDS) in the oil phase under a DC electric field is investigated by molecular dynamics simulation. The effects of electric field strength and oil type on the electrocoalescence of two water droplets are mainly considered. The trajectory snapshots and center of mass of the two water droplets suggest that there is almost no migratory coalescence. The movement of sodium ions and SDS, which is a combined effect of the electric field force and the resistance from the oil phase, is crucial for the deformation and connection of two water droplets. The results of mean square displacement, radial distribution function, hydration number, and interaction energies of Na + -H 2 O and SDS-H 2 O indicate that the sodium ion has a stronger ability to carry water molecules for movement than SDS. The stronger electric field strength will result in more severe deformation and shorter coalescence time. Under the higher electric field strength, the two droplets will be elongated into a slender water ribbon. By applying a pulsed DC electric field with suitable amplitude, frequency, and duty ratio, it is possible to achieve full coalescence for the ionic surfactant-stabilized W/O emulsions. The oil phase also plays an important role for the deformation of droplets and the migration of emulsion components. For the different oil phases, a longer time or stronger electric field strength would be needed for the electrocoalescence of droplets in the oil phase with higher density and viscosity. Our results are expected to be helpful for practical application in the petroleum industry and chemical engineering.

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“…Droplets’ size for bare O/W emulsions prepared at different concentrations and HLB values showed a normal distribution ( Figure 3A ). Here, we obtained a mean hydrodynamic diameter D[4,3] of approximately 1 μm, which is an appropriate droplet size to avoid precipitation or any other instability phenomena ( Yang et al, 2019 ). These results were also observed for all the emulsions even after 95 days.…”

Section: Resultsmentioning

confidence: 99%

Formulation of a novel antibacterial topical treatment based on Magnetite-Buforin-II-silver nanobioconjugates

Muñoz

Jaramillo

Gantiva-Diaz

et al. 2022

Front. Bioeng. Biotechnol.

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Community acquired infections caused by Meticillin-resistant Staphylococcus aureus (MRSA) have become a growing concern due to its impact on the world public health. This microorganism is a commonly spreading pathogen associated predominantly with skin infections and connected to other more severe conditions (septic shock, and generalized infection). The lack of highly effective antibiotics and treatments to control skin infections with S. aureus has led to the search of novel therapies using alternative agents such as antimicrobial peptides (AMPs). In order to obtain a viable administration route to counteract superficial skin infections (impetigo, abscesses, furuncles, and cellulitis), a topical formulation based on Magnetite-Buforin-II-silver nanobioconjugates as active antibacterial agents was designed by their dispersion in O/W concentrated emulsions. The prepared topical characterization indicated that O/W emulsions were stable in time, the droplets size remained within the appropriate values (∼1 µm) and their rheological properties, such as pseudoplastic and shear-thinning behavior, remained unchanged for up to 3 months. Additionally, hemolysis and platelet aggregation tests were acceptable (i.e., 14.72 ± 2.62% and 8.06 ± 2.90%, respectively) in compliance with the ISO-10993 standard. Furthermore, the treatment reduced significantly (p < 0.0001) the growth of both clinical isolated MRSA and wild Type S. aureus strains as evidenced by the contact diffusion method. These results are important in the context of proposing new alternatives that allow manage effectively the threat posed by the antibiotic resistant bacterial strains, which jeopardize the lives of thousands of people every year.

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Partial coalescence of droplets at oil–water interface subjected to different electric waveforms: Effects of non-ionic surfactant on critical electric field strength

Cited by 17 publications

References 38 publications

Effect of electric field on coalescence of an oil-in-water emulsion stabilized by surfactant: a molecular dynamics study

Effect of electric field on coalescence of an oil-in-water emulsion stabilized by surfactant: a molecular dynamics study

Molecular Dynamics Study on the Demulsification Mechanism of Water-In-Oil Emulsion with SDS Surfactant under a DC Electric Field

Formulation of a novel antibacterial topical treatment based on Magnetite-Buforin-II-silver nanobioconjugates

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