Temperature-induced Coalescence of Droplets Manipulated by Optical Trapping in an Oil-in-Water Emulsion

Mitsunobu, Manami; Kobayashi, S.; Takeyasu, Nobuyuki; Kaneta, Takashi

doi:10.2116/analsci.33.709

Cited by 14 publications

(8 citation statements)

References 35 publications

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“…Reducing the repulsive force originating from the electrical double layer is expected to lead to increased probability for spontaneous coalesce between emulsion droplets when brought to proximity. Temperature effects would also change droplet coalescence time, as increased thermal energy has been shown to decrease the interfacial tension in bulk crude oil, 8 and reduce coalescence time in micromanipulated droplets, 9 although for the small size ranges of the latter, temperature control has proved to be inaccurate. This de-stabilization of emulsions have become important especially within the petroleum industry, where wastewater biproduct from drilling contains a variety of petroemulsions.…”

Section: Introductionmentioning

confidence: 99%

Exploring the effects of approach velocity on depletion force and coalescence in oil-in-water emulsions

2021

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Section: Introductionmentioning

confidence: 99%

Exploring the effects of approach velocity on depletion force and coalescence in oil-in-water emulsions

2021

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“…Microfluidic devices have achieved high rates of recovery, but these require sophisticated fabrication techniques and complex pumping systems [20–22]. Compared with these separation methods, manipulation using optical force, which is generally employed in techniques such as laser trapping or the use of optical tweezers [23], is useful for the collection and manipulation of small droplets and vesicles [24–27]. Optical force permits the trapping of objects such as particles or cells via the focus of a laser beam.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of optical force acting on vesicles via the binding of gold nanoparticles

Tani

Kaneta

2019

R. Soc. open sci.

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Here we found that gold nanoparticles (AuNPs) enhance the optical force acting on vesicles prepared from phospholipids via hydrophobic and electrostatic interactions. A laser beam was introduced into a cuvette filled with a suspension of vesicles and it accelerated them in its propagation direction via a scattering force. The addition of the AuNPs exponentially increased the velocity of the vesicles as their concentration increased, but polystyrene particles had no significant impact on velocity in the presence of AuNPs. To elucidate the mechanism of the increased velocity, the surface charges in the vesicles and the AuNPs were controlled; the surface charges of the vesicles were varied via the use of anionic, cationic and neutral phospholipids, whereas AuNPs with positive and negative charges were synthesized by coating with citrate ion and 4-dimethylaminopyridine, respectively. All vesicles increased the velocity at different degrees depending on the surface charge. The vesicles were accelerated more efficiently when their charges were opposite those of the AuNPs. These results suggested that hydrophobic and electrostatic interactions between the vesicles and the AuNPs enhanced the optical force. By accounting for the binding constant between the vesicles and the AuNPs, we proposed a model for the relationship between the concentration of the AuNPs and the velocity of the vesicles. Consequently, the increased velocity of the vesicles was attributed to the light scattering that was enhanced when AuNPs were adsorbed onto the vesicles.

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“…Recent analytical studies of emulsions include evaluations of collapse processes, 1,2 analysis of the interface of droplets, 3−5 and analysis of emulsion products. 6 Turbidity measured by ultraviolet–visible spectrophotometry (UV–vis) has normally been used for the evaluation of emulsion stability.…”

Section: Introductionmentioning

confidence: 99%

Evaluating the Creaming of an Emulsion via Mass Spectrometry and UV–Vis Spectrophotometry

Shinoda

Uchimura

2018

ACS Omega

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The creaming behavior of a turbid oil-in-water emulsion was observed via the processes of multiphoton ionization time-of-flight mass spectrometry (MPI-TOFMS) and ultraviolet–visible spectrophotometry (UV–vis), and the results were compared. The transmittance measurement by UV–vis showed that the turbidity of the toluene emulsion was decreased with time. However, non-negligible errors are common in the measurement of a sample with high turbidity. The online measurement by MPI-TOFMS detected many spikes in the time profile, which revealed the existence of toluene droplets in the emulsion. A smooth time profile suggested that the signal intensity had initially increased, and then decreased with time; the initial concentration of toluene was 3 g/L, which had decreased by half after 60 min. The signal behavior obtained using MPI-TOFMS differed only slightly from that obtained using UV–vis. Since a change in turbidity is not the same as a change in the local concentration of an oil component, MPI-TOFMS is useful for the analysis of a turbid emulsion and offers additional information concerning the creaming phenomenon of an emulsion.

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Temperature-induced Coalescence of Droplets Manipulated by Optical Trapping in an Oil-in-Water Emulsion

Cited by 14 publications

References 35 publications

Exploring the effects of approach velocity on depletion force and coalescence in oil-in-water emulsions

Exploring the effects of approach velocity on depletion force and coalescence in oil-in-water emulsions

Enhancement of optical force acting on vesicles via the binding of gold nanoparticles

Evaluating the Creaming of an Emulsion via Mass Spectrometry and UV–Vis Spectrophotometry

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