scholarly journals A numerical study of one-patch colloidal particles: from square-well to Janus

2010 ◽  
Vol 12 (38) ◽  
pp. 11869 ◽  
Author(s):  
Francesco Sciortino ◽  
Achille Giacometti ◽  
Giorgio Pastore
Keyword(s):  
Colloidal Particles ◽  
Numerical Study ◽  
Square Well

Numerical Study on Electrokinetic Interaction Between a Pair of Cylindrical Colloidal Particles

2009 ◽  
Author(s):  
Dolfred Vijay Fernandes ◽  
Sangmo Kang ◽  
Yong Kweon Suh
Keyword(s):  
Flow Field ◽  
Electric Field ◽  
Colloidal Particles ◽  
Stokes Equations ◽  
Separation Efficiency ◽  
Numerical Study ◽  
Interaction Force ◽  
Surface Element ◽  
Immersed Boundary ◽  
Interaction Forces

Electrophoresis is the motion of dispersed particles relative to a fluid under the influence of an electric field. Presently this phenomenon of electrokinetics is widely used in biotechnology for the separation of proteins, sequencing of polypeptide chains etc. The separation efficiency of these biomolecules is affected by their aggregation. Thus it is important to study the interaction forces between the molecules. In this study we calculate the electrophoretic motion of a pair of colloidal particles under axial electric field. The hydrodynamic and electric double layer (EDL) interaction forces are calculated numerically. The EDL interaction force is calculated from electric field distribution around the particle using Maxwell stress tensor and the hydrodynamic force is calculated from the flow field obtained from the solution of Stokes equations. The continuous forcing approach of immersed boundary method is used to obtain flow field around the moving particles. The EDL distribution around the particles is obtained by solving Poisson-Nernst-Planck (PNP) equations on a hybrid grid system. The EDL interaction force calculated from numerical solution is compared with the one obtained from surface element integration (SEI) method.

Early Dynamics and Stabilization Mechanisms of Oil-in-Water Emulsions Containing Colloidal Particles Modified with Short Amphiphiles: A Numerical Study

Langmuir ◽  
2017 ◽  
Vol 33 (50) ◽  
pp. 14347-14357 ◽  
Author(s):  
Manuella Cerbelaud ◽  
Arnaud Videcoq ◽  
Lauriane Alison ◽  
Elena Tervoort ◽  
André R. Studart
Keyword(s):  
Colloidal Particles ◽  
Numerical Study ◽  
Oil In Water

scholarly journals Self-assembly mechanism in colloids: perspectives from statistical physics

Open Physics ◽  
2012 ◽  
Vol 10 (3) ◽  
Author(s):  
Achille Giacometti
Keyword(s):  
Integral Equation ◽  
Self Assembly ◽  
Hard Sphere ◽  
Statistical Physics ◽  
Colloidal Particles ◽  
Building Blocks ◽  
Computational Effort ◽  
Spherical Particles ◽  
Square Well ◽  
Patchy Colloids

AbstractMotivated by recent experimental findings in chemical synthesis of colloidal particles, we draw an analogy between self-assembly processes occurring in biological systems (e.g. protein folding) and a new exciting possibility in the field of material science. We consider a self-assembly process whose elementary building blocks are decorated patchy colloids of various types, that spontaneously drive the system toward a unique and predetermined targeted macroscopic structure. To this aim, we discuss a simple theoretical model — the Kern-Frenkel model — describing a fluid of colloidal spherical particles with a pre-defined number and distribution of solvophobic and solvophilic regions on their surface. The solvophobic and solvophilic regions are described via a short-range square-well and a hard-sphere potentials, respectively. Integral equation and perturbation theories are presented to discuss structural and thermodynamical properties, with particular emphasis on the computation of the fluid-fluid (or gas-liquid) transition in the temperaturedensity plane. The model allows the description of both one and two attractive caps, as a function of the fraction of covered attractive surface, thus interpolating between a square-well and a hard-sphere fluid, upon changing the coverage. By comparison with Monte Carlo simulations, we assess the pros and the cons of both integral equation and perturbation theories in the present context of patchy colloids, where the computational effort for numerical simulations is rather demanding.

BOUND, VIRTUAL AND RESONANCE STATES OF THE THREE-DIMENSIONAL DIRAC AND SCHRÖDINGER SQUARE WELL

2013 ◽  
Vol 22 (11) ◽  
pp. 1350079
Author(s):  
H. HOGREVE
Keyword(s):  
Perturbation Methods ◽  
Numerical Study ◽  
Three Dimensional ◽  
Spherically Symmetric ◽  
Rigorous Results ◽  
Resonance States ◽  
S Matrix ◽  
Symmetric Square ◽  
Square Well ◽  
Transition Scenario

The transition scenario between bound, virtual and resonance states is investigated for the Dirac and Schrödinger operator with a spherically symmetric square well potential of varying depth λ≥0. This includes rigorous results derived with the help of the Birman–Schwinger principle and perturbation methods, and a numerical study of the motion of the corresponding S-matrix poles as a function of λ by displaying the computed energy curves in the complex plane.

scholarly journals Lipid membrane-mediated attraction between curvature inducing objects

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Casper van der Wel ◽  
Afshin Vahid ◽  
Anđela Šarić ◽  
Timon Idema ◽  
Doris Heinrich ◽  
...  
Keyword(s):  
Colloidal Particles ◽  
Lipid Membrane ◽  
Numerical Study ◽  
Particle Diameter ◽  
Interaction Force ◽  
Membrane Curvature ◽  
Coarse Grained ◽  
Cellular Transport ◽  
Curvature Energy ◽  
Membrane Deformations

Abstract The interplay of membrane proteins is vital for many biological processes, such as cellular transport, cell division, and signal transduction between nerve cells. Theoretical considerations have led to the idea that the membrane itself mediates protein self-organization in these processes through minimization of membrane curvature energy. Here, we present a combined experimental and numerical study in which we quantify these interactions directly for the first time. In our experimental model system we control the deformation of a lipid membrane by adhering colloidal particles. Using confocal microscopy, we establish that these membrane deformations cause an attractive interaction force leading to reversible binding. The attraction extends over 2.5 times the particle diameter and has a strength of three times the thermal energy (−3.3 kBT). Coarse-grained Monte-Carlo simulations of the system are in excellent agreement with the experimental results and prove that the measured interaction is independent of length scale. Our combined experimental and numerical results reveal membrane curvature as a common physical origin for interactions between any membrane-deforming objects, from nanometre-sized proteins to micrometre-sized particles.

Numerical Study of Liquid Film Microstructure During Spin Coating of Ag Colloidal Suspension

2009 ◽  
Author(s):  
Yongli Zhao ◽  
Albert Ratner ◽  
Jeffrey S. Marshall
Keyword(s):  
Thin Film ◽  
Spin Coating ◽  
Colloidal Particles ◽  
Numerical Study ◽  
Colloidal Suspension ◽  
Particle Collision ◽  
Coating Process ◽  
Multiple Time ◽  
Adhesion Forces ◽  
Time Step

A multiple time-step discrete-element approach is employed to model the transport, collision and adhesion of small silver (Ag) colloidal particles in a spin coating process. The three-dimensional (3D) particle motions are computed using a combination of fluid-induced forces and torques, and forces and torques induced by the particle collision and adhesion forces. These analysis are used to predict the final aggregate size distribution and microstructure during the non-evaporative phase of spin coating of a thin film, which is important for controlling the abrasiveness, opacity, conductivity, and other properties of the film, as well as for using the deposited particles for growing new materials (e.g., nanotubes). The computations examine the effect of adhesion potential, volume concentration, and spin speed effects on the distribution of particle aggregate sizes and their deposition during spin coating. The aggregates are observed to be primarily governed by these parameters, as has previously been observed in experiments. The results provide a fundamental understanding of the physics of thin film spin coating processes and insight in to microstructure control during the coating process.

scholarly journals Numerical study of the phase behavior of rod-like colloidal particles with attractive tips

AIP Advances ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 025030
Author(s):  
Justin T. Jack ◽  
Paul C. Millett
Keyword(s):  
Phase Behavior ◽  
Colloidal Particles ◽  
Numerical Study

scholarly journals Effect of Nanostructure on Thermal Conductivity of Nanofluids

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Saba Lotfizadeh ◽  
Themis Matsoukas
Keyword(s):  
Thermal Conductivity ◽  
Colloidal Particles ◽  
Volume Fraction ◽  
Numerical Study ◽  
Hollow Spheres ◽  
Structural Features ◽  
Solid Particles ◽  
Spherical Particles ◽  
Colloidal Gel ◽  
The One

The presence of colloidal particles is known to increase the thermal conductivity of base fluids. The shape and structure of the solid particles are important in determining the magnitude of enhancement. Spherical particles—the only shape for which analytic theories exist—produce the smallest enhancement. Nonspherical shapes, including clusters formed by colloidal aggregation, provide substantially higher enhancements. We conduct a numerical study of the thermal conductivity of nonspherical structures dispersed in a liquid at fixed volume fraction in order to identify structural features that promote the conduction of heat. We find that elongated structures provide high enhancements, especially if they are long enough to create a solid network (colloidal gel). Cross-linking further enhances thermal transport by directing heat in multiple directions. The most efficient structure is the one formed by hollow spheres consisting of a solid shell and a core filled by the fluid. In both dispersed and aggregated forms, hollow spheres provide enhancements that approach the theoretical limit set by Maxwell’s theory.

Ultrastructure of Lymphatic Capillaries in the Transport of Colloidal Particles

1967 ◽  
Vol 25 ◽  
pp. 186-187
Author(s):  
L. V. Leak ◽  
J. F. Burke
Keyword(s):  
Connective Tissue ◽  
Colloidal Particles ◽  
Ultrastructural Level ◽  
Vital Role ◽  
Time Intervals ◽  
Thorium Dioxide ◽  
Lymphatic Capillary ◽  
Tissue Area ◽  
Rapid Removal ◽  
Tissue Fluids

The vital role played by the lymphatic capillaries in the transfer of tissue fluids and particulate materials from the connective tissue area can be demonstrated by the rapid removal of injected vital dyes into the tissue areas. In order to ascertain the mechanisms involved in the transfer of substances from the connective tissue area at the ultrastructural level, we have injected colloidal particles of varying sizes which range from 80 A up to 900-mμ. These colloidal particles (colloidal ferritin 80-100A, thorium dioxide 100-200 A, biological carbon 200-300 and latex spheres 900-mμ) are injected directly into the interstitial spaces of the connective tissue with glass micro-needles mounted in a modified Chambers micromanipulator. The progress of the particles from the interstitial space into the lymphatic capillary lumen is followed by observing tissues from animals (skin of the guinea pig ear) that were injected at various time intervals ranging from 5 minutes up to 6 months.

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