Active structuring of colloidal armour on liquid drops

Dommersnes, Paul; Rozynek, Zbigniew; Mikkelsen, Arne; Castberg, Rene; Kjerstad, Knut; Hersvik, Kjetil; Fossum, Jon Otto

doi:10.1038/ncomms3066

Cited by 110 publications

(123 citation statements)

References 43 publications

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“…If the drop is not fully covered, Taylor electrohydrodynamic circulation flows in and around the drop would induce the formation of particle ribbons on the drop surface by convective deposition in the flow field [19,20,21]. Such flows are not observed around the fully armored drops studied here since the particle layer absorbsim the tangential electrostatic stresses.…”

Section: Experiments On Quincke Rotation Of a Single Particle Laden Dropmentioning

confidence: 79%

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Electro-hydrodynamic propulsion of counter-rotating Pickering drops

Dommersnes

Mikkelsen

Fossum

2016

Eur. Phys. J. Spec. Top.

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Insulating particles or drops suspended in carrier liquids may start to rotate with a constant frequency when subjected to a uniform DC electric field. This is known as the Quincke rotation electro-hydrodynamic instability. A single isolated rotating particle exhibit no translational motion at low Reynolds number, however interacting rotating particles may move relative to one another. Here we present a simple system consisting of two interacting and deformable Quincke rotating particle covered drops, i.e. deformable Pickering drops. The drops attract one another and spontaneously form a counter-rotating pair that exhibits electro-hydrodynamic driven propulsion at low Reynolds number flow.

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Section: Experiments On Quincke Rotation Of a Single Particle Laden Dropmentioning

confidence: 79%

“…The preparation of the Pickering emulsion drops was similar to that of reference [19,20,21] ). The suspension of PE particles in silicone oil was stirred and ultra-sonicated to avoid particle aggregation.…”

Section: Experiments On Quincke Rotation Of a Single Particle Laden Dropmentioning

confidence: 87%

Electro-hydrodynamic propulsion of counter-rotating Pickering drops

Dommersnes

Mikkelsen

Fossum

2016

Eur. Phys. J. Spec. Top.

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“…Such a complex topological structure is bound to interfere with the mechanical response of the shell in a way that is still unclear. Understanding this point, however, is of utmost importance to control the deformation of many functionalized self-assembled materials (9,18,19). Numerical and theoretical approaches to date are typically based on solving the elasticity field between grain-boundary scars and deriving equilibrium particle configurations from the effective free energy of the interacting defects (15,(20)(21)(22)(23).…”

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confidence: 99%

Deformation and failure of curved colloidal crystal shells

Negri

Sellerio

Zapperi

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Designing and controlling particle self-assembly into robust and reliable high-performance smart materials often involves crystalline ordering in curved spaces. Examples include carbon allotropes like graphene, synthetic materials such as colloidosomes, or biological systems like lipid membranes, solid domains on vesicles, or viral capsids. Despite the relevance of these structures, the irreversible deformation and failure of curved crystals is still mostly unexplored. Here, we report simulation results of the mechanical deformation of colloidal crystalline shells that illustrate the subtle role played by geometrically necessary topological defects in controlling plastic yielding and failure. We observe plastic deformation attributable to the migration and reorientation of grain boundary scars, a collective process assisted by the intermittent proliferation of disclination pairs or abrupt structural failure induced by crack nucleating at defects. Our results provide general guiding principles to optimize the structural and mechanical stability of curved colloidal crystals.T he morphology of crystals becomes peculiar when selfassembled on curved shells. For example, the Gaussian curvature of a sphere demands the presence of geometrically necessary rotational defects (disclinations) such as the 12 pentagons in a soccer ball. Disclinations can be found in thin shell structures at different length scales: from the world of carbon allotropes (1) [as in fullerenes, nanotubes, and graphene (2)] to biological systems [such as in lipid membranes (3), solid domains on vesicles (4, 5), or in viral capsids (6-8)], and in synthetic structures such as colloidosomes, colloidal particle shells lying at the interface between two fluids (9-12). Thin-shell structures are often conceived for encapsulation purposes at various scales (i.e., as delivery vehicles of different kinds of cargo, from drugs to flavors and cosmetics) and arise naturally in biological systems. Examples include crystalline and glassy colloidosomes, capsules of Janus and patchy particles, nematic vesicles, and viral capsids.Theoretical considerations indicate that arranging a colloidal crystal into a curved geometry involves elastic deformation and the presence of geometrically necessary disclinations showed by simulations to be attached to extended grain boundary scars (13-15), as also confirmed in several experiments (5,9,16,17). Thus, grain boundary scars are different from standard grain boundaries in that they have a nonzero disclination charge, which makes them more costly. Such a complex topological structure is bound to interfere with the mechanical response of the shell in a way that is still unclear. Understanding this point, however, is of utmost importance to control the deformation of many functionalized self-assembled materials (9,18,19). Numerical and theoretical approaches to date are typically based on solving the elasticity field between grain-boundary scars and deriving equilibrium particle configurations from the effective free energy of the...

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“…15. Janus colloidal capsule made by electro-coalescence with the assistance of EHD flows [45] (visualization): The initial droplets partially covered by surface particles assembled at electric equators by EHD flows (a). The droplets attract one another by means of both the EHD flows and electrostatic interaction.…”

Section: Summary and Perspectivesmentioning

confidence: 99%

Patchy colloidosomes – an emerging class of structures

Rozynek

Józefczak

2016

Eur. Phys. J. Spec. Top.

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Abstract.A colloidosome, i.e., a selectively permeable capsule composed of colloidal particles forming a stable homogenous shell, is a tiny container that can be used for storage, transportation, and release of cargo species. There are many routes to preparing colloidosomes; dozens of examples of future applications of such colloidal capsules have been demonstrated. Their functionality can be further extended if the capsules are designed to have heterogeneous shells, i.e., one or more regions (patches) of a shell are composed of material with specific properties that differ from the rest of the shell. Such patchy colloidosomes, supplemented by functionalities similar to that offered by well-studied patchy particles, will surely possess advantageous properties when compared with their homogenous counterparts. For example, owing to specific interactions between patches, they either can self-assemble into complex structures; specifically adhere to a surface; release their cargo species in specific direction; or guided-align,-orient or -propel. Fabrication of patchy colloidal microcapsules has long been theorized by scientists able to design different models, but actual large-scale production remains a challenge. Until now, only a few methods for fabricating patchy colloidosomes have been demonstrated, and these include production by means of microfluidics and mechanical pipetting. The field of science related to fabrication and application of patchy colloidosomes is clearly unexplored, and we envision it blooming in the coming years.

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Active structuring of colloidal armour on liquid drops

Cited by 110 publications

References 43 publications

Electro-hydrodynamic propulsion of counter-rotating Pickering drops

Electro-hydrodynamic propulsion of counter-rotating Pickering drops

Deformation and failure of curved colloidal crystal shells

Patchy colloidosomes – an emerging class of structures

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