Related Experiment Video
Updated: Feb 12, 2026
04:42
Bacterial Cellulose Spheres that Encapsulate Solid Materials
Published on: February 26, 2021
5.0K
Stick boundary condition at large hard sphere arising from effective attraction in binary hard-sphere mixtures
Yuka Nakamura1, Akira Yoshimori2, Ryo Akiyama3
1Department of Physics, Kyushu University, Fukuoka 812-0395, Japan.
The Journal of Chemical Physics
|April 2, 2018
Summary
We studied how large solute spheres move in binary mixtures. The solvent sphere size ratio significantly impacts solute diffusion, transitioning from slip to stick boundary conditions due to density changes.
Area of Science:
- Physics
- Physical Chemistry
- Materials Science
Background:
- Understanding solute diffusion in complex fluids is crucial for various applications.
- Hard-sphere models provide fundamental insights into fluid behavior.
- The influence of solvent properties on solute dynamics requires detailed investigation.
Purpose of the Study:
- To investigate the diffusion of a large hard-sphere solute in binary hard-sphere mixtures.
- To determine how the boundary condition at the solute surface is influenced by the surrounding solvent density.
- To analyze the effect of the size ratio of binary solvent spheres on the solute's boundary condition.
Main Methods:
- Solving equations for a binary compressible mixture using perturbation expansions.
- Analyzing the dependence of the boundary condition on the size ratio of binary solvent spheres.
- Investigating the role of solvent density and entropic effects.
Main Results:
- The boundary condition is dependent on the size ratio of the binary solvent spheres.
- A size ratio of 1:2 results in a boundary condition close to the slip boundary condition.
- A large size ratio leads to a boundary condition approaching the stick boundary condition.
- An increase in solvent density around the solute, driven by an entropic effect, causes the transition to the stick boundary condition.
Conclusions:
- The boundary condition for solute diffusion in binary hard-sphere mixtures is tunable via the solvent size ratio.
- Entropic effects play a key role in modifying solvent density and influencing diffusion dynamics.
- This study provides a theoretical framework for predicting and controlling solute transport in multi-component systems.
Related Concept Videos
01:22Toughness and Hardness of Aggregate
641
Toughness and hardness are critical properties of aggregate materials used in concrete, particularly on pavement surfaces and industrial flooring subjected to heavy loads. Toughness is defined as the aggregate's resistance to failure by impact and is measured by the aggregate impact value (AIV). For this, the aggregate impact value test is performed, wherein the impact is delivered by a standard hammer, which falls freely under its own weight onto the aggregates. The aggregates fragment in...
641
01:22Electric Field of a Non Uniformly Charged Sphere
2.3K
Gauss's law states that the electric flux through any closed surface equals the net charge enclosed within the surface. This law is beneficial for determining the expressions for the electric field for a particular charge distribution if the electric flux is known.
Consider a non-uniformly charged sphere, for which the density of charge depends only on the distance from a point in space and not on the direction. Such a sphere has a spherically symmetrical charge distribution. Here, the electric...
Consider a non-uniformly charged sphere, for which the density of charge depends only on the distance from a point in space and not on the direction. Such a sphere has a spherically symmetrical charge distribution. Here, the electric...
2.3K
01:16Electrostatic Boundary Conditions
982
Consider an external electric field propagating through a homogeneous medium. When the electric field crosses the surface boundary of the medium, it undergoes a discontinuity. The electric field can be resolved into normal and tangential components. The amount by which the field changes at any boundary is given by the difference between the field components above and below the surface boundary.
The surface integral of an electric field is given by Gauss's law in integral form and is related to...
The surface integral of an electric field is given by Gauss's law in integral form and is related to...
982
01:28Magnetostatic Boundary Conditions
1.7K
An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...
1.7K
01:25Boundary Conditions for Current Density
1.3K
Current density becomes discontinuous across an interface of materials with different electrical conductivities. The normal component of the current density is continuous across the boundary.
1.3K
01:21Boundary Conditions: Lossless Lines
438
Consider a single-phase, two-wire, lossless transmission line terminated by an impedance at the receiving end and a source with Thevenin voltage and impedance at the sending end. The line, with length, has a surge impedance and wave velocity determined by the line's inductance and capacitance.
At the receiving end, the boundary condition states that the voltage equals the product of the receiving-end impedance and current. This relationship is expressed as a function of the incident and...
At the receiving end, the boundary condition states that the voltage equals the product of the receiving-end impedance and current. This relationship is expressed as a function of the incident and...
438