Shape of a Random-Flight Chain

Šolc, Karel

doi:10.1063/1.1675527

Cited by 286 publications

(146 citation statements)

References 10 publications

Supporting

Mentioning

135

Contrasting

Unclassified

Order By: Relevance

“…The description of the geometrical properties of complex systems by generalized parameters such as the radius of gyration or principal components of the gyration tensor has a long history in macromolecular chemistry and biophysics [24,36,37]. Indeed, such descriptors allow an evaluation of the overall shape of a system and reveal its symmetry.…”

Section: System Characterisation: Droplets and Nanoparticlesmentioning

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

Section: System Characterisation: Droplets and Nanoparticlesmentioning

confidence: 99%

Buckling in armored droplets

Sicard

Striolo

2017

Nanoscale

View full text Add to dashboard Cite

show abstract

“…The description of the geometrical properties of complex systems by generalized parameters such as the radius of gyration or principal components of the gyration tensor has a long history in macromolecular chemistry and biophysics [33,34]. Indeed, such descriptors allow an evaluation of the overall shape of a system (spherical, oblate, or prolate) and reveal its symmetry.…”

Section: Droplet Characteristicsmentioning

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

“…Star polymers with small arm numbers (f = 1, 2) resemble linear polymers. Thus, their configurations show a considerable asphericity [8][9][10], although their chain-averaged number density of monomers, φ(r), is spherically symmetric around the center of mass of the polymer. With increasing arm number f , the asphericity of the stars has been shown to decrease considerably [11][12][13][14][15][16][17][18][19], leading to "stiff" spherical particles in the limit of high f .…”

Section: Introductionmentioning

confidence: 99%

Polydisperse star polymer solutions

et al. 2000

View full text Add to dashboard Cite

We analyze the effect of polydispersity in the arm number on the effective interactions, structural correlations and the phase behavior of star polymers in a good solvent. The effective interaction potential between two star polymers with different arm numbers is derived using scaling theory. The resulting expression is tested against monomer-resolved molecular dynamics simulations. We find that the theoretical pair potential is in agreement with the simulation data in a much wider polydispersity range than other proposed potentials. We then use this pair potential as an input in a many-body theory to investigate polydispersity effects on the structural correlations and the phase diagram of dense star polymer solutions. In particular we find that a polydispersity of 10%, which is typical in experimental samples, does not significantly alter previous findings for the phase diagram of monodisperse solutions.

show abstract

Shape of a Random-Flight Chain

Cited by 286 publications

References 10 publications

Buckling in armored droplets

Buckling in armored droplets

Numerical analysis of Pickering emulsion stability: insights from ABMD simulations

Polydisperse star polymer solutions

Contact Info

Product

Resources

About