Composite interfacial layers containing micro-size and nano-size particles

Miller, R.; Fainerman, V. B.; Kovalchuk, V. I.; Grigoriev, D. O.; Leser, Martin E.; Michel, Martin

doi:10.1016/j.cis.2006.11.004

Cited by 62 publications

(55 citation statements)

References 109 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When nanoparticles (NPs) are used as emulsifiers, their characteristics might have critical effects on properties such as interfacial tension [6], droplet size, and emulsion stability [7][8][9][10][11][12][13]. Although the factors affecting Pickering emulsion stability are still a key topic of research, the density of NPs on the droplet surface is known to be among the most important parameters [14].…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of Pickering emulsion stability: insights from ABMD simulations

Sicard

Striolo

2016

Faraday Discuss.

View full text Add to dashboard Cite

The issue of the stability of Pickering emulsions is tackled at a mesoscopic level using dissipative particle dynamics simulations within the Adiabatic Biased Molecular Dynamics framework. We consider the early stage of the coalescence process between two spherical water droplets in decane solvent. The droplets are stabilized by Janus nanoparticles of different shapes (spherical and ellipsoidal) with different three-phase contact angles. Given a sufficiently dense layer of particles on the droplets, we show that the stabilization mechanism strongly depends on the collision speed. This is consistent with a coalescence mechanism governed by the rheology of the interfacial region. When the system is forced to coalesce sufficiently slowly, we investigate at a mesoscopic level how the ability of the nanoparticles to stabilize Pickering emulsions is discriminated by nanoparticle mobility and the associated caging effect. These properties are both related to the interparticle interaction and the hydrodynamic resistance in the liquid film between the approaching interfaces.

show abstract

Section: Introductionmentioning

confidence: 99%

Numerical analysis of Pickering emulsion stability: insights from ABMD simulations

Sicard

Striolo

2016

Faraday Discuss.

View full text Add to dashboard Cite

show abstract

“…[1][2][3][4][5][6][7][8] The energy of adsorption W is related to the contact angle  of the particle with the interface: W =   R 2 (1 ± cos) 2 for spherical particles, where R is the radius of the particle and   the surface tension of the bare interface (free of particles). When  ~ 90°, W ~ (R/a) 2 kT, a being a molecular size, k the Boltzmann constant and T the absolute temperature, indicating that since W >> kT, the adsorption is irreversible.…”

Section: Introductionmentioning

confidence: 99%

An ellipsometry study of silica nanoparticle layers at the water surface

Zang

Stocco

Langévin

et al. 2009

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

We have studied silica nanoparticle layers spread at the air-water interface. The surface pressure of the layers has been determined in a Langmuir trough via two orthogonal Wilhelmy plates. We observed significant differences in surface pressure according to the preparation protocol: layers spread then compressed or layers obtained after successive spreading steps. We also studied the two types of layers by multiple angle of incidence ellipsometry. We introduce a two-layer model which enables us to evaluate the radius of interfacial aggregates and their contact angle with the air-water interface.

show abstract

“…The characteristics of Pickering emulsions pose a number of intriguing fundamental physical questions including a thorough understanding of the perennial lack of detail about how particles arrange at the liquid/liquid interface. Other not completely answered questions include particle effects on interfacial tension [7], layering [8], buckling [9-11] and particle release [8,12].In some important processes that involve emulsions, it can be required to reduce the volume of the dispersed droplets [9,[13][14][15]. The interface may undergo large deformations that produce compressive stresses, causing localized mechanical instabilities.…”

mentioning

confidence: 99%

Buckling in armored droplets

Sicard

Striolo

2017

Nanoscale

View full text Add to dashboard Cite

The issue of the buckling mechanism in droplets stabilized by solid particles (armored droplets) is tackled at a mesoscopic level using dissipative particle dynamics simulations. We consider spherical water droplet in a decane solvent coated with nanoparticle monolayers of two different types: Janus and homogeneous. The chosen particles yield comparable initial three-phase contact angles, chosen to maximize the adsorption energy at the interface. We study the interplay between the evolution of droplet shape, layering of the particles, and their distribution at the interface when the volume of the droplets is reduced. We show that Janus particles affect strongly the shape of the droplet with the formation of a crater-like depression. This evolution is actively controlled by a close-packed particle monolayer at the curved interface. On the contrary, homogeneous particles follow passively the volume reduction of the droplet, whose shape does not deviate too much from spherical, even when a nanoparticle monolayer/bilayer transition is detected at the interface. We discuss how these buckled armored droplets might be of relevance in various applications including potential drug delivery systems and biomimetic design of functional surfaces.Keywords: Pickering emulsions, DPD simulations, Janus/homogeneous nanoparticles, bucklingPickering emulsions [1], i.e. particle-stabilized emulsions, have been studied intensively in recent years owning to their wide range of applications including biofuel processing [2] and food preservation [3,4]. They have also been developed as precursors to magnetic particles for imaging [5] and drug delivery systems [6]. Even with their widespread use, they remain, however, underutilized. In Pickering emulsions, particles and/or nanoparticles (NPs) with suitable surface chemistries adsorb at the droplet surfaces, with an adsorption energy of up to thousands of times the thermal energy. The characteristics of Pickering emulsions pose a number of intriguing fundamental physical questions including a thorough understanding of the perennial lack of detail about how particles arrange at the liquid/liquid interface. Other not completely answered questions include particle effects on interfacial tension [7], layering [8], buckling [9-11] and particle release [8,12].In some important processes that involve emulsions, it can be required to reduce the volume of the dispersed droplets [9,[13][14][15]. The interface may undergo large deformations that produce compressive stresses, causing localized mechanical instabilities. The proliferation of these localized instabilities may then result in a variety of collapse mechanisms [8,10,11]. Despite the vast interest in particle-laden interfaces, the key factors that determine the collapse of curved particle-laden interfaces are still subject of debate. Indeed, although linear elasticity describes successfully the morphology of buckled particle-laden droplets, it is still unclear whether the onset of buckling can be explained in terms of classic elastic buckling...

show abstract

Composite interfacial layers containing micro-size and nano-size particles

Cited by 62 publications

References 109 publications

Numerical analysis of Pickering emulsion stability: insights from ABMD simulations

Numerical analysis of Pickering emulsion stability: insights from ABMD simulations

An ellipsometry study of silica nanoparticle layers at the water surface

Buckling in armored droplets

Contact Info

Product

Resources

About