Hydrodynamic interaction between a capsule and a solid boundary in unbounded Stokes flow

Keh, Martin; Walter, J.; Leal, L. Gary

doi:10.1063/1.4901298

Cited by 5 publications

(5 citation statements)

References 30 publications

(48 reference statements)

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“…The drainage time can be obtained as a dimensionless using a capillary time scale. [65][66][67] According to scaling theory, [65,68] the dimensionless drainage time (τ = μR 0 /t d γ) was calculated with the experimental results scaling as τ ≈ Ca 0.5 , which was consistent with the theoretical results obtained using the Reynolds lubrication equation (Figure 6b). Compared to the random distribution of the adsorption tendency described by thermodynamic theories (Figures 1a and 6a), an ordered tendency of particle adsorption was observed.…”

Section: Drainage Dynamics In the Model Systemsupporting

confidence: 82%

Controlled Adsorption of Cellulose Nanofibrils on Fluid–Fluid Interfaces

Kim

Han

You

et al. 2023

Adv Materials Inter

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applications, such as emulsion stabilization, [1] membrane transduction, [2,3] nanocomposites, [4] drug delivery, [5,6] and the fabrication of advanced materials with micro-and nanostructures. [7][8][9][10] In general, adsorption at the interface is explained by the thermodynamic energy difference ΔE ad = − Aγ ow (1 − |cos θ|), where A is the projection area of the particle in contact with the interface, γ ow is the interfacial tension, and θ is the contact angle. Microparticles and sub-micron particles are bound irreversibly at the interface because of the enormous reduction in interfacial energy (typically thousands to millions [10 3 -10 6 ] times the thermal energy). [16][17][18]20,29] Thus, nearly any particle with a proper size and surface properties, unless they are superhydrophilic or superhydrophobic with nanometer size, is readily adsorbed at the interface in an irreversible manner.However, non-adsorbing particles are frequently observed even with a large binding energy, and in this case, external forces such as mechanical, thermal, and chemical actuation are required for successful particle adsorption. [30][31][32] An example of difficult adsorption is the low interfacial tension of an oil/ water interface. It was consistently found that the lower the interfacial tension at the oil/water interface, the more difficult the adsorption of various particles such as nanocellulose (i.e., cellulose nanocrystal (CNC) [16] and cellulose nanofibrils (CNFs) [18,33,34] ), silica, [17] magnetite, [19] and graphene oxide. [21] A typical explanation for the difficult adsorption at low interfacial tension is the relatively low binding energy. [16][17][18][19]21] However, the binding energy is still several thousand times larger than the thermal energy-even at low interfacial tensions (≈5 mN m −1 ) (Figure 1a). Thus, the relationship between difficult adsorption and substantial adsorption energies is contradictory. Accordingly, conventional thermodynamic theories alone cannot clearly explain the difficult adsorption process. It might be more closely related with the "process" of particle adsorption rather than differences in energy "state".Before a particle adsorbs at an interface, a few intermediate steps occur. Initially, particles are transported to a nearby drop by external shear flow, [37] Brownian motion, [38] or external fields, such as gravity [30] and an electric field. [39] As the gap between the solid and drop surfaces becomes narrower, the fluid in the gap is drained out. [30,40] It is well known that drainage dynamics play a major role in the interfacial adsorption of particles as Adsorption of particles at fluid-fluid interfaces is of great scientific and industrial importance, encompassing a variety of applications, from the stabilization of bubbles and emulsions to the fabrication of sophisticated materials with micro-and nanostructures. The enormous adsorption energy of a particle is believed to be the origin of adsorption, but it cannot fully explain many systems that do not adsorb, even with large ads...

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Section: Drainage Dynamics In the Model Systemsupporting

confidence: 82%

Controlled Adsorption of Cellulose Nanofibrils on Fluid–Fluid Interfaces

Kim

Han

You

et al. 2023

Adv Materials Inter

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“…The electrostatic nature of lipid molecules (a hydrophobic tail and a hydrophilic head with an electric dipole) complicates the interactions between a lipid bilayer membrane and another bilayer membrane [40][41][42][43] or a solid (such as a glass substrate or a nano particle). Adhesion between a vesicle and a solid has been extensively studied with more focus on the static equilibrium shapes [44][45][46][47][48][49][50][51][52][53][54][55][56] than the transient adhesion process [57][58][59]. Adhesive interactions between lipid membranes are essential in many biomedical, biological, and biophysical processes.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamics and rheology of a vesicle doublet suspension

2019

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The dynamics of an adhesive two-dimensional vesicle doublet under various flow conditions is investigated numerically using a high-order, adaptive-in-time boundary integral method. In a quiescent flow, two nearby vesicles move slowly towards each other under the adhesive potential, pushing out fluid between them to form a vesicle doublet at equilibrium. A lubrication analysis on such draining of a thin film gives the dependencies of draining time on adhesion strength and separation distance that are in good agreement with numerical results. In a planar extensional flow we find a stable vesicle doublet forms only when two vesicles collide head-on around the stagnation point. In a microfluid trap where the stagnation of an extensional flow is dynamically placed in the middle of a vesicle doublet through an active control loop, novel dynamics of a vesicle doublet are observed. Numerical simulations show that there exists a critical extensional flow rate above which adhesive interaction is overcome by the diverging stream, thus providing a simple method to measure the adhesion strength between two vesicle membranes. In a planar shear flow, numerical simulations reveal that a vesicle doublet may form provided that the adhesion strength is sufficiently large at a given vesicle reduced area. Once a doublet is formed, its oscillatory dynamics is found to depend on the adhesion strength and their reduced area. Furthermore the effective shear viscosity of a dilute suspension of vesicle doublets is found to be a function of the reduced area. Results from these numerical studies and analysis shed light on the hydrodynamic and rheological consequences of adhesive interactions between vesicles in a viscous fluid.Keywords: Vesicle hydrodynamics, membrane adhesion, drop and bubble phenomena/drop interactions, interfacial flows/thin fluid films, rheology/flow confinement, biological fluid dynamics/collective behavior/clustering, emergence of patterns

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“…More recently, the non-linear elastic model and the viscoelastic properties of the membrane were deduced in the regime of large deformations [13] and from the dynamic of tank-treading in simple shear flow [21] for HSA microcapsules. Numerical simulations play a major role to identify the relevant mechanical properties of the membrane [22] as its constitutive law [13,23], its viscosity [24] or its bending modulus [25]. Experimental and numerical studies on microcapsules in flow have focused a strong attention to the shape and its dynamics but not on the flow around it and notably on the perturbation of the applied flow.…”

Section: Introductionmentioning

confidence: 99%

Perturbations of the flow induced by a microcapsule in a capillary tube

et al. 2017

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Soft microcapsules moving in a cylindrical capillary deform from quasi-spherical shapes to elongated shapes with an inversion of curvature at the rear. We investigated the perturbation of the flow by particle tracking velocimetry around deformed microcapsules in confined flow. These experiments are completed by numerical simulations. Microcapsules are made of a thin membrane of polymerized human albumin and their shear elastic moduli are previously characterized in a cross flow chamber. Firstly, the velocity of the microcapsule can be calculated by theoretical predictions for rigid spheres, even for large deformations as 'parachute-like' shapes, if a relevant definition of the ratio of confinement is chosen. Secondly, at the rear and the front of the microcapsule, the existence of multiple recirculation regions is governed by the local curvature of the membrane. The amplitudes of these perturbations increase with the microcapsule deformation, whereas their axial extents are comparable to the radius of the capillary whatever the confinement and the capillary number. We conclude that whereas the motion of microcapsules in confined flow has quantitative similitudes with rigid spheres in term of velocity and axial extent of the perturbation, their presence induces variations in the flow field that are related to the local deformation of the membrane as in droplets.

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Hydrodynamic interaction between a capsule and a solid boundary in unbounded Stokes flow

Cited by 5 publications

References 30 publications

Controlled Adsorption of Cellulose Nanofibrils on Fluid–Fluid Interfaces

Controlled Adsorption of Cellulose Nanofibrils on Fluid–Fluid Interfaces

Hydrodynamics and rheology of a vesicle doublet suspension

Perturbations of the flow induced by a microcapsule in a capillary tube

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