Effect of Shear Flow on Nanoparticles Migration near Liquid Interfaces

The effect of shear flow on spherical nanoparticles (NPs) migration near a liquid–liquid interface is studied by numerical simulation. We have implemented a compact model through which we use the diffuse interface method for modeling the two fluids and the molecular dynamics method for the simulation of the motion of NPs. Two different cases regarding the state of the two fluids when introducing the NPs are investigated. First, we introduce the NPs randomly into the medium of the two immiscible liquids that are already separated, and the interface is formed between them. For this case, it is shown that before applying any shear flow, 30% of NPs are driven to the interface under the effect of the drag force resulting from the composition gradient between the two fluids at the interface. However, this percentage is increased to reach 66% under the effect of shear defined by a Péclet number Pe = 0.316. In this study, different shear rates are investigated in addition to different shearing times, and we show that both factors have a crucial effect regarding the migration of the NPs toward the interfacial region. In particular, a small shear rate applied for a long time will have approximately the same effect as a greater shear rate applied for a shorter time. In the second studied case, we introduce the NPs into the mixture of two fluids that are already mixed and before phase separation so that the NPs are introduced into the homogenous medium of the two fluids. For this case, we show that in the absence of shear, almost all NPs migrate to the interface during phase separation, whereas shearing has a negative result, mainly because it affects the phase separation.

[1]  Beom-Jin Lee,et al.  Effects of shear stress on the cellular distribution of polystyrene nanoparticles in a biomimetic microfluidic system , 2016 .

[2]  James M. Tour,et al.  Polymer-Coated Nanoparticles for Enhanced Oil Recovery , 2014 .

[3]  Elizabeth I. Maurer,et al.  The effect of shear flow on nanoparticle agglomeration and deposition in in vitro dynamic flow models , 2015, Nanotoxicology.

[4]  P. Clegg,et al.  Fluid-bicontinuous gels stabilized by interfacial colloids: low and high molecular weight fluids , 2008, Journal of physics. Condensed matter : an Institute of Physics journal.

[5]  N. Djilali,et al.  Direct numerical simulations of agglomeration of circular colloidal particles in two-dimensional shear flow , 2016 .

[6]  B. Minofar,et al.  Effect of Nitrogen Doping on Glass Transition and Electrical Conductivity of [EMIM][PF6] Ionic Liquid Encapsulated in a Zigzag Carbon Nanotube , 2017 .

[7]  R. Aveyard,et al.  Particle zips: vertical emulsion films with particle monolayers at their surfaces. , 2005, Langmuir : the ACS journal of surfaces and colloids.

[8]  D. Papavassiliou,et al.  The effects of shear and particle shape on the physical adsorption of polyvinyl pyrrolidone on carbon nanoparticles , 2016, Nanotechnology.

[9]  Patrick Patrick Anderson,et al.  Cahn–Hilliard modeling of particles suspended in two‐phase flows , 2012 .

[10]  L. Bécu,et al.  Strain-induced droplet retraction memory in a pickering emulsion. , 2009, Langmuir : the ACS journal of surfaces and colloids.

[11]  Michel Dorget,et al.  Viscosity-induced filler localisation in immiscible polymer blends , 2015 .

[12]  J. Lowengrub,et al.  Quasi–incompressible Cahn–Hilliard fluids and topological transitions , 1998, Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.

[13]  A. Ammar,et al.  Nanoparticles migration near liquid-liquid interfaces using diffuse interface model , 2019, Engineering Computations.

[14]  C. Monteux,et al.  Colloidal Particle Adsorption at Water-Water Interfaces with Ultralow Interfacial Tension. , 2017, Physical Review Letters.

[15]  Y. Joo,et al.  Coarse-grained molecular dynamics simulation on the placement of nanoparticles within symmetric diblock copolymers under shear flow. , 2008, The Journal of chemical physics.

[16]  S. Bon,et al.  Pickering Stabilized Miniemulsion Polymerization: Preparation of Clay Armored Latexes , 2005 .

[17]  A. Márquez,et al.  Influence of the Blend Viscosity and Interface Energies on the Preferential Location of CB and Conductivity of BR/EPDM Blends , 2003 .

[18]  T. Emrick,et al.  Preparation of cadmium selenide-polyolefin composites from functional phosphine oxides and ruthenium-based metathesis. , 2002, Journal of the American Chemical Society.

[19]  P. Cassagnau,et al.  Morphology and rheology of immiscible polymer blends filled with silica nanoparticles , 2007 .

[20]  P. Cassagnau,et al.  Immiscible polymer blends stabilized with nano-silica particles: Rheology and effective interfacial tension , 2008 .

[21]  G. Whitesides.  The 'right' size in nanobiotechnology , 2003, Nature Biotechnology.

[22]  Y. Joo,et al.  Effect of shear on nanoparticle dispersion in polymer melts: A coarse-grained molecular dynamics study. , 2010, The Journal of chemical physics.

[23]  Navid B. Saleh,et al.  Oil-in-water emulsions stabilized by highly charged polyelectrolyte-grafted silica nanoparticles. , 2005, Langmuir : the ACS journal of surfaces and colloids.

[24]  S. Nguyen,et al.  Hybrid nanoparticles with block copolymer shell structures , 1999 .

[25]  John E. Hilliard,et al.  Free Energy of a Nonuniform System. III. Nucleation in a Two‐Component Incompressible Fluid , 1959 .