Spherically Confined Colloidal Suspensions Of Hydrodynamically Interacting Particles
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Spherically Confined Colloidal Suspensions Of Hydrodynamically Interacting Particles
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Author : Christian Alberto Aponte Rivera
language : en
Publisher:
Release Date : 2017
Spherically Confined Colloidal Suspensions Of Hydrodynamically Interacting Particles written by Christian Alberto Aponte Rivera and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
The diffusion in and rheology of hydrodynamically interacting colloids confined by a spherical cavity via dynamic simulation is studied as a model for intracellular and other confined biophysical transport. The modeling of transport and rheology in such confined inhomogeneous soft materials requires an accurate description of the microscopic forces driving particle motion, such as entropic and hydrodynamic forces, and of particle interactions with nearby boundaries. Previous models of such micro-confined transport behavior had been limited primarily to a single particle inside a spherical cavity. Although attempts had been made prior to this work to extend such models to more than one confined particle, none had yet successfully accounted for the effects of hydrodynamics, owing to the difficulties of modeling many-body long-ranged interactions. To accurately model spherically confined suspensions, new far-field mobility functions are derived and, together with the appropriate near-field resistance functions, implemented in a Stokesian-dynamics like approach. The method fully accounts for all many-body far-field interactions and near-field interactions both between the particles themselves and between particles and the enclosing cavity. Utilizing the newly developed method, we study short- and long- time self-diffusion at equilibrium, with a focus on the dependence of the former on particle positions relative to the cavity, and of both on volume fraction and size ratio. It is found that the cavity exerts qualitative changes in transport behavior, such as a position dependent and anisotropic short-time self-diffusivity and anisotropic long-time transport behavior. Such qualitative changes suggest that careful interpretation of experimental measurements in 3D confined suspensions requires accounting for such confinement induced behaviors. To elucidate the effects of confinement on inter-particle hydrodynamic interactions, the method is utilized to determine the concentrated mobility of particles in the spherically confined domain. Confinement is found to induce qualitative changes in the functional dependence of particle entrainment with inter-particle separation. For widely separated particles, the functional dependence on inter-particle separation can be predicted via a Green's function. How this behavior can be utilized to develop a more accurate framework for two-point microrheology measurements near confining boundaries is discussed.
The Rheology Of Polydisperse Colloidal Suspensions In Spherical Confinement
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Author : Emma del Carmen Gonzalez Gonzalez
language : en
Publisher:
Release Date : 2021
The Rheology Of Polydisperse Colloidal Suspensions In Spherical Confinement written by Emma del Carmen Gonzalez Gonzalez and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.
In this work, we present a computational study of the rheology and dynamics of spherically-confined polydisperse suspensions of hydrodynamically interacting colloids, a simple model system that provides an important framework for studying the behavior of living and non-living confined colloidal suspensions. Colloids are microscopically small particles suspended in a solvent. Examples include the cytoplasm of biological cells, micro-reactor vesicles, and particle-laden droplets ubiquitous in additive manufacturing and industrial coatings. Here we present an extension of the Confined Stokesian Dynamics algorithm (CSD) capable of modeling the bulk rheology of confined colloidal suspensions of arbitrary particle-size distribution, at and away from equilibrium. We will present novel hydrodynamic functions we developed that couple particle dynamics to suspension properties and, after a brief overview of the CSD algorithm, the results of a systematic study of the impact of changes in confinement and size polydispersity on equilibrium structure and dynamics. We showed that an interplay between polydispersity and confinement reveals demixing and localized dynamics that help explain our previous discovery that such dynamics control the speedup of protein synthesis in faster-growing bacteria. Next, we will present a new theoretical framework we developed for measuring the intrinsic viscosity and osmotic pressure in confined suspensions. The first significant outcome of this work was that tighter confinement and crowding significantly increase equilibrium viscous dissipation and osmotic pressure compared to unconfined suspensions. This result is important for the rational design of biochemical tests, where up to now, only the effect of passive crowders was taken into account. The second significant outcome of this work was the modeling of strong departures from equilibrium, including a representation of biomolecules localized at one pole of the cavity that subsequently diffuse - mimicking the Min cycle in E. coli our work shows that concentration gradients inside cells increase the residence time of proteins close to the membrane, which is beneficial for Min-protein membrane reaction kinetics that promotes correct cell division. Finally, we will present three other significant theoretical developments in the field of microhydrodynamics done in service of the underlying theoretical framework of our model.
Colloids In Confined Geometries Hydrodynamics Simulation And Rheology
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Author : James W. Swan
language : en
Publisher:
Release Date : 2010
Colloids In Confined Geometries Hydrodynamics Simulation And Rheology written by James W. Swan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Colloids categories.
The hydrodynamics of colloids in confined geometries is studied hierarchically beginning with the exact solutions for a spherical particle translating, rotating and deforming in the presence of a plane wall at low Reynolds number. The many-bodied hydrodynamic interactions among a collection of spherical particles near a plane wall are computed and used to study the Brownian motion of confined suspensions. The method of reflections is used to describe the motion of a single spherical particle embedded in the fluid constrained by two, parallel plane walls. From this, tables which are independent of the channel width are generated describing the particle's response to various force moments. This same approach is expanded to describe the hydrodynamic interactions among the particles comprising a colloidal dispersion confined in a channel. The simulations arising from this theory depict the short-time self-diffusivity, sedimentation rate and high frequency viscosity of suspensions of varying volume fractions in channels of varying widths. A theory for the scattering of evanescent waves by colloidal dispersions is developed and cast in the form of the diffusivity measured by classical light scattering. A series of simulations is conducted to predict the short- time self-diffusivity and the collective diffusivity measured by evanescent wave dynamic light scattering. The thesis concludes with a discussion of how the developed simulations and theories can be extended to make dynamic measurements as well as a brief consideration of some remaining, open questions.
Hydrodynamic Interactions Of Colloidal Particles In Confined Geometry
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Author : Sukalyan Bhattacharya
language : en
Publisher:
Release Date : 2005
Hydrodynamic Interactions Of Colloidal Particles In Confined Geometry written by Sukalyan Bhattacharya and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with categories.
Colloidal Suspension Rheology
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Author : Jan Mewis
language : en
Publisher: Cambridge University Press
Release Date : 2012
Colloidal Suspension Rheology written by Jan Mewis and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with Science categories.
Presented in an accessible and introductory manner, this is the first book devoted to the comprehensive study of colloidal suspensions.
Hydrodynamic Effects On Active Colloidal Suspensions
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Author : Eloy Navarro Argemí
language : en
Publisher:
Release Date : 2019
Hydrodynamic Effects On Active Colloidal Suspensions written by Eloy Navarro Argemí and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with categories.
The goal of this thesis is studying hydrodynamic effects on active colloidal suspensions. Hydrodynamic interaction is propagated through the fluid in which the colloids displace due to the flow they create during their motion. It can lead to the emergence of collective phenomena, such as the self-assembly of more complex structures. Hydrodynamic interactions are not the only present in the system, since other forces may be acting between colloids, or there can be external fields acting on them such as gravity. We present our study for two different systems: magnetic colloids and Janus particles. When applying a circular magnetic field, we can induce a rotation to a particle possessing a magnetic moment. Due to the coupling of the flow with the one created by surrounding particles and with system interfaces, a rotor will eventually self-propel. Two magnetic moments interact with each other through the magnetic dipole-dipole force, which tends to align them into arrays. We study how the balance between hydrodynamic, magnetic and gravitational forces determines the morphology of the structures magnetic colloids can form. Janus particles have two faces with different chemical properties, thus the interaction between them depends on their relative orientation. We study the morphology and order of the structures that can emerge for these particles as a function of the intensity, sign and reach of the interaction between them, as well as the type of flow they create when self-propelling. Methodologically, we have combined the use of far-field theory to draw analytical expressions that have given us qualitative insight on the results we could expect with high-performance computing simulations which have allowed us to extend our study to bigger systems.
Suspensions Of Colloidal Particles And Aggregates
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Author : Frank Babick
language : en
Publisher: Springer
Release Date : 2018-04-25
Suspensions Of Colloidal Particles And Aggregates written by Frank Babick and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-04-25 with Technology & Engineering categories.
This book addresses the properties of particles in colloidal suspensions. It has a focus on particle aggregates and the dependency of their physical behaviour on morphological parameters. For this purpose, relevant theories and methodological tools are reviewed and applied to selected examples. The book is divided into four main chapters. The first of them introduces important measurement techniques for the determination of particle size and interfacial properties in colloidal suspensions. A further chapter is devoted to the physico-chemical properties of colloidal particles—highlighting the interfacial phenomena and the corresponding interactions between particles. The book’s central chapter examines the structure-property relations of colloidal aggregates. This comprises concepts to quantify size and structure of aggregates, models and numerical tools for calculating the (light) scattering and hydrodynamic properties of aggregates, and a discussion on van-der-Waals and double layer interactions between aggregates. It is illustrated how such knowledge may significantly enhance the characterisation of colloidal suspensions. The final part of the book refers to the information, ideas and concepts already presented in order to address technical aspects of the preparation of colloidal suspensions—in particular the performance of relevant dispersion techniques and the stability of colloidal suspensions.
Brownian Dynamics Of Colloidal Suspensions
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Author : Ward Evan TeGrotenhuis
language : en
Publisher:
Release Date : 1990
Brownian Dynamics Of Colloidal Suspensions written by Ward Evan TeGrotenhuis and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1990 with categories.
Phase Behavior And Effective Interactions In Colloidal Suspensions
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Author :
language : en
Publisher: Cuvillier Verlag
Release Date : 2007-04-25
Phase Behavior And Effective Interactions In Colloidal Suspensions written by and has been published by Cuvillier Verlag this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007-04-25 with Science categories.
Colloidal suspensions describe particles with size from typically a few nanometers to a few microns which are dispersed in a medium. In physics, in chemistry, and in biology colloids play an important role and the study of colloidal systems underwent a recent renaissance. This is based on the development of experimental techniques, the availability of extensive computer simulations and well-developed theoretical approaches. From a technological point of view, the relevance of micro- and nanostructured materials and the presence of colloids in nature and everyday life motivates study of this rich field. In this thesis the phase behavior and the effective interactions of colloidal suspensions in bulk, in contact with surfaces, and in confined geometry are studied. For mixtures of particles with hard-core interactions the model introduced by Asakura, Oosawa and Vrij provides an appropriate starting-point. Based on that model the free-volume theory and the density functional theory are employed. In experimental systems one faces particles with properties such as the size or the shape which are described by a distribution. To capture that issue a generalized approach based on free-volume theory for treating mixtures of colloids and a polydisperse depletion agent is presented. Within that approach it is possible to treat size and morphology polydispersity. A depletion agent with a bimodal distribution possessing two length scales can be studied. Though the Asakura-Oosawa-Vrij model describes a simple fluid - a mixture of hard spheres and ideal polymer - the phenomenology is rather rich: in contact with a wall one finds layering and wetting effects and in confined geometry of a narrow pore one finds capillary condensation. The competition between both effects manifests itself in thermodynamic properties like the excess colloid adsorption and the solvation force between the two confining walls. Solvent phase separation complicates the evaluation of interparticle interactions between the solute particles. We address this question for the wall-colloid and the colloid-colloid geometry. For a non-spherical particle the effect of curvature on thermodynamic quantities is studied.
Investigating Flow Behaviors Of Colloidal Materials At The Single Particle Scale
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Author : Yen-Chih Lin
language : en
Publisher:
Release Date : 2017
Investigating Flow Behaviors Of Colloidal Materials At The Single Particle Scale written by Yen-Chih Lin and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
My thesis work focuses on the nonlinear mechanical behaviors of colloidal suspensions at the particle-level. This work covers both quiescent and strongly sheared suspensions. For quiescent suspensions, we image their 3D structures with confocal microscopy, and implement Stress Assessment from Local Structural Anisotropy (SALSA) to visualize the stress fields in them. Unlike traditional numerical methods, SALSA takes a statistical approach converting the probability of hard-sphere Brownian collisions to stresses. This direct stress measurement allows us to quantify the particle-level stresses surrounding vacancies, dislocations, and grain boundaries in crystalline materials. To drive the suspensions away from equilibrium, we develop a confocal-rheoscope, which is able to shear and image colloidal materials simultaneously. Using this device, we investigate the nonlinear flow behavior governed by Brownian motion, shear induced diffusion, and advection, and more importantly, disentangle them. We also study particle assembly and its corresponding rheological properties under confinement. Finally, we study even more strongly sheared suspensions, in which particle dynamics are too fast to be imaged by a confocal microscope. Here, we use flow reversal rheometry to reveal the underlying mechanism of suspension shear thickening where the viscosity increases with shear rate. We show that the thickening behavior of a suspension arises from the particle contact forces rather than hydrodynamic interactions. Such findings then lead us to design a biaxial shear protocol that can tune the suspension viscosity on demand. This viscosity tuning capability is a foundational step toward using dense suspensions in 3D printing, energy storage, and robotics. ...