Osmotic pressure and chemical potential of silica nanoparticles in aqueous poly(ethyleneoxide) solution

Quant, Carlos A.; Marla, Krishna Tej; Meredith, J. Carson

doi:10.1016/j.colsurfa.2007.10.004

Cited by 14 publications

(8 citation statements)

References 32 publications

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“…On the basis of these observations, we propose a mechanism behind the formation of internal droplets inside the PE/NP AWE-somes and their dependence on the NP concentration. At the initial introduction ( t = 0) of dextran-PE droplets to the PEG-NP external phase, there exists a clean interface across which there is an osmotic pressure imbalance (Π PEG > Π dex ) likely due to highly concentrated NP suspension (Figure a). , When the first NPs flux toward the interface and begin to complex with the PE from the dextran phase, the initial membrane is both rigid and highly permeable (Figure b). Prior studies have indeed shown that complexes of NP and PE form porous materials .…”

Section: Resultsmentioning

confidence: 99%

AWE-somes: All Water Emulsion Bodies with Permeable Shells and Selective Compartments

Hann

Stebe

Lee

2017

ACS Appl. Mater. Interfaces

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Living cells exploit compartmentalization within organelles to spatially and temporally control reactions and pathways. Here, we use the all aqueous two phase system (ATPS) of poly(ethylene glycol) (PEG) and dextran to develop all water emulsion bodies, AWE-somes, a new class of encapsulated double emulsions as potential cell mimics. AWE-somes feature rigid polyelectrolyte (PE)/nanoparticle (NP) shells and double emulsion interiors. The shells form via complexation of PE and NP at interfaces of ATPS. The NPs, excluded from the drop phase, create an osmotic stress imbalance that removes water from the encapsulated phase and draws droplets of external PEG phase into the shells to form the double emulsion interior. We demonstrate that molecules can permeate the AWE-some shells, selectively partition into the internal droplets, and undergo reaction. AWE-somes have significant potential for creating functional, biocompatible protocell systems.

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Section: Resultsmentioning

confidence: 99%

AWE-somes: All Water Emulsion Bodies with Permeable Shells and Selective Compartments

Hann

Stebe

Lee

2017

ACS Appl. Mater. Interfaces

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“…From equating the summation of capillary and osmotic forces with the viscous force, r / R f = C 2 t /τ o , where C 2 is the experimental constant and τ o = (μ m R f )/[(γ/ R + π) R ]. π is the osmotic pressure, and its magnitude is ∼50 Pa, estimated from the literature . The plot of r / R f versus cos(θ) t /τ o in Figure f shows that all cases collapse into a single curve.…”

Section: Resultsmentioning

confidence: 90%

Wetting Dynamics of Nanoparticle Dispersions: From Fully Spreading to Non-sticking and the Deposition of Nanoparticle-Laden Surface Droplets

Bazazi

Hejazi

2022

ACS Appl. Mater. Interfaces

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Controlled transport of liquid droplets on solid surfaces is critical in many practical applications, such as self-cleaning surfaces, coating, drug delivery, and agriculture. Non-adhesive liquid drops levitate on solid surfaces; therefore, they are highly mobile and directed toward desired locations by external stimuli. Although research on liquid-repellent surfaces has proliferated, the existing methods are still limited to creating surface roughness or coating the liquid droplets. Here, we create non-contact aqueous drops on hydrophilic surfaces in an oleic environment and use them to deposit submicrometer droplets encapsulating nanoparticles on solid surfaces. A glass surface is buried under an oil phase that contains a high concentration of Span 80 surfactants, and a drop of silica nanoparticle dispersion is released on the solid surface. We study the effect of surfactant concentration in oil and nanoparticle concentration in water on wetting dynamics and report a plethora of droplet spreading regimes from fully wetting to non-wetting. We find a threshold Span 80 concentration above which surfactant assemblies are formed on the solid and prevent the direct contact of the drop with the surface. At the same time, water-in-oil emulsions are generated at the drop–oil interface. The drop moves and leaves a trace of emulsions with encapsulated nanoparticles on the solid. We demonstrate the possibility of local surface coating with hydrophilic nanoparticles in a hydrophobic medium. The developed methodology in this study is a generic approach facilitating the droplet patterning in numerous applications, from pharmaceutical polymetric carriers to the formulation of cosmetics, insecticides, and biomedical diagnoses.

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“…33,34 Although PS particles may exert a small osmotic pressure in the inner phase, it is negligible compared to that exerted by NaCl solution, resulting in the shrinkage of the inner droplets until closepacking of PS particles is achieved. 35 As the distance between PS particles gradually decreases and the concentration of PS particles in the inner phase (f) increases during osmotic annealing, double emulsions start to exhibit brilliant structural colours.…”

Section: Resultsmentioning

confidence: 99%

Angle- and strain-independent coloured free-standing films incorporating non-spherical colloidal photonic crystals

Yeo

Kim

et al. 2015

Soft Matter

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Colloidal photonic crystals (CPCs) provide a convenient way to generate structural colour with high stability against degradation under environmental factors. For a number of applications including flexible electronic and energy devices, it is important to generate flexible structural colour that maintains its colour regardless of the angle of observation and the extent of mechanical deformation. However, it is challenging to simultaneously achieve these goals because anisotropy in typical CPC structures (e.g., CPC films) tends to lead to angle-dependent photonic properties and also changes in the lattice constant due to mechanical deformation lead to changes in the photonic properties of CPCs. To overcome these challenges, we present a means of fabricating large-area free-standing films of CPC structures that exhibit angle- and strain-independent photonic characteristics. First, monodisperse double emulsions encapsulating colloidal crystal arrays are prepared using a microfluidic device. By inducing crystallization of highly charged polystyrene particles in the core of double emulsions using osmotic annealing, we generate angle independent colloidal photonic crystal (CPC) supraparticles. Moreover, the shape and crystallinity of the CPC supraparticles can be tuned by changing the concentration of salt in the solution used for osmotic annealing. Subsequently, an array of CPC supraparticles is embedded inside an elastomeric matrix to form a flexible free-standing film, which exhibits structural colours that are independent of viewing angles and externally applied strain.

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Osmotic pressure and chemical potential of silica nanoparticles in aqueous poly(ethyleneoxide) solution

Cited by 14 publications

References 32 publications

AWE-somes: All Water Emulsion Bodies with Permeable Shells and Selective Compartments

AWE-somes: All Water Emulsion Bodies with Permeable Shells and Selective Compartments

Wetting Dynamics of Nanoparticle Dispersions: From Fully Spreading to Non-sticking and the Deposition of Nanoparticle-Laden Surface Droplets

Angle- and strain-independent coloured free-standing films incorporating non-spherical colloidal photonic crystals

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