Monodisperse emulsions from a microfluidic device, characterised by diffusion NMR

Woodward, Andrew M.; Cosgrove, Terence; Espidel, J.; Jenkins, Paul J.; Shaw, N.

doi:10.1039/b616463n

Cited by 35 publications

(33 citation statements)

References 43 publications

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“…As already indicated by Eqn , especially in case of small, mono‐disperse droplets combined with large diffusion times, the signal attenuation as function of gradient amplitude is not monotonic. The signal attenuation is similar to that observed for diffusion inside mono‐disperse spheres . A simulation of Eqn for discrete droplet sizes shows the non‐monotonic behaviour (Fig.…”

Section: Dsd Modellingsupporting

confidence: 77%

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NMR on emulsions: characterisation of liquid dispersed systems

Bernewitz¹,

Guthausen²,

Schuchmann³

2011

Magnetic Reson in Chemistry

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Pulsed field gradient NMR (PFG-NMR) is an important method for the characterisation of emulsions. Apart from its application in quality control and process development, especially high-field NMR methods can be applied to investigate emulsions properties on the molecular level. Meanwhile, complex emulsion structures such as double emulsions have been developed and require analytical tools especially for the determination of droplet size distributions. This contribution provides an overview on the possibilities and methods of PFG-NMR referring to measurement, data processing and interpretation of droplet size distributions. Comparison of techniques and measurements on double emulsions are presented.

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Section: Dsd Modellingsupporting

confidence: 77%

“…The signal attenuation is similar to that observed for diffusion inside mono-disperse spheres. [77] A simulation of Eqn (3) for discrete droplet sizes shows the non-monotonic behaviour (Fig. 5).…”

Section: Dsd Modelling Single Emulsionsmentioning

confidence: 94%

NMR on emulsions: characterisation of liquid dispersed systems

Bernewitz¹,

Guthausen²,

Schuchmann³

2011

Magnetic Reson in Chemistry

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“…Droplets have been generated in flow-focusing devices (Woodward et al 2007;Tan et al 2006;Yobas et al 2006;Anna et al 2003) or by T-junctions (Priest et al 2006;Nisisako et al 2002;Thorsen et al 2001). In recent studies, more complicated designs were proposed for improved manipulation of droplets.…”

mentioning

confidence: 99%

Droplet dynamics passing through obstructions in confined microchannel flow

Chung

Lee

Char

et al. 2010

Microfluid Nanofluid

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Motivated by the previous studies (Lee et al., Lab Chip 10:1160-1166, 2010 Link et al., Phys Rev Lett 92:054503-1-054503-4, 2004), the droplet dynamics passing through obstructions in confined microchannel was explored both numerically and experimentally. The effects of obstruction shape (cylinder and square), droplet size, and capillary number (Ca) on droplet dynamics were investigated. For the size control, due to an obstructioninduced droplet breakup, the cylinder obstruction was found to be advantageous over square type for practical purposes. The thread breakup was attributed to both normal and shear components of velocity gradients near the obstruction, in particular, near the corners of the square. As a result, the square obstruction was considered to generate more non-trivial satellite droplets. The droplet size showed little influence on the droplet dynamics. Considering the wetting process on the cylinder surface, we explored the droplet dynamics passing through two successive cylinder obstructions, where more complicated dynamics was observed depending on Ca (capillary number * viscous force / interface tension), cylinder interval, and droplet size. Here, we propose two requirements for independent wetting on each cylinder: (i) low Ca droplet should be manipulated, and (ii) cylinder interval should be larger than channel width. That is, low Ca droplet could intrude the region between two cylinders if the cylinder interval was far enough, while the droplet could not intrude due to geometric hindrance for close obstructions. In the numerical viewpoint, the proposed requirements were also valid for multi-cylinder obstructions up to 6. In addition, we propose a novel design of array structure of cylinders for a selective wetting, which might be useful to fabricate Janus particles. We hereby prove by both simulation and experiments that the wetting on the obstruction is controllable by changing Ca and cylinder design in the multilayer deposition process.

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“…[12] Moreover, microfluidic technology offers a powerful tool for investigating the properties of emulsions themselves. [15], [16] In this work, particle-stabilized oil in water emulsions were formed in a T-junction microfluidic device. The stability of the emulsions as a function of concentration of salt (NaCl) and hydrophilic Laponite RD nanoparticles in the aqueous phase was studied to determine the conditions necessary to form stable systems.…”

Section: Introductionmentioning

confidence: 99%

Controlled microfluidic emulsification of oil in a clay nanofluid: Role of salt for Pickering stabilization

Gholamipour‐Shirazi

Carvalho

Fossum

2016

Eur. Phys. J. Spec. Top.

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Abstract.Research on emulsions is driven by their wide-spreading use in different industries, such as food, cosmetic, pharmaceutical and oil recovery. Emulsions are stabilized by suitable surfactants (electrostatic stabilization), polymers, solid particles (steric stabilization) or a combination of them. Microfluidic emulsification is the process of droplet formation out of two or more liquids under strictly controlled conditions, without preemulsification step. Microfluidic technology offers a powerful tool for investigating the properties of emulsions themselves. In this work stable oil in water emulsions were formed with hydrophilic Laponite RD® nanoparticles adsorbed at the interface of the oil phase and aqueous clay nanofluid in a T junction microfluidic chip. Emulsions stability up to at least 40 days could be observed.

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Monodisperse emulsions from a microfluidic device, characterised by diffusion NMR

Cited by 35 publications

References 43 publications

NMR on emulsions: characterisation of liquid dispersed systems

NMR on emulsions: characterisation of liquid dispersed systems

Droplet dynamics passing through obstructions in confined microchannel flow

Controlled microfluidic emulsification of oil in a clay nanofluid: Role of salt for Pickering stabilization

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