Related Experiment Video
Updated: Feb 8, 2026

13:15
Quantitative and Qualitative Examination of Particle-particle Interactions Using Colloidal Probe Nanoscopy
Published on: July 18, 2014
11.5K
Thermophoretic torque in colloidal particles with mass asymmetry
Juan Olarte-Plata1, J Miguel Rubi2, Fernando Bresme1
1Department of Chemistry, Imperial College London, London SW7 2AZ, United Kingdom.
Physical Review. E
|June 17, 2018
Summary
Anisotropic colloids in a thermal field rectify rotational motion, leading to unique Soret coefficient behavior. This contrasts with homogeneous colloids, showing a maximum instead of monotonic force increase.
Area of Science:
- Colloid science
- Statistical mechanics
- Soft matter physics
Background:
- Colloids in thermal gradients exhibit thermophoresis.
- Anisotropic particles possess unique responses to external fields.
- Understanding particle dynamics in fluids is crucial for material science.
Purpose of the Study:
- To investigate the thermophoretic behavior of anisotropic colloids.
- To explore the influence of internal mass distribution on colloid orientation and motion.
- To analyze the relationship between Soret coefficient and colloid mass for anisotropic particles.
Main Methods:
- Nonequilibrium molecular dynamics (NEMD) simulations.
- Nonequilibrium thermodynamics theory.
- Analysis of rotational Brownian motion and transient torques.
Main Results:
- Anisotropic mass distribution rectifies rotational Brownian motion.
- Colloids experience transient torques, aligning with the thermal field.
- Soret coefficient shows a maximum dependence on colloid mass, differing from homogeneous colloids.
Conclusions:
- Internal anisotropy dictates colloid response to thermal fields.
- The observed Soret coefficient behavior offers a new mechanism for particle manipulation.
- This study provides insights into the physics of anisotropic particles in thermal gradients.
Related Concept Videos
Colloids
21.2K
Children at play often make suspensions such as mixtures of mud and water, flour and water, or a suspension of solid pigments in water known as tempera paint. These suspensions are heterogeneous mixtures composed of relatively large particles that are visible to the naked eye or can be seen with a magnifying glass. They are cloudy, and the suspended particles settle out after mixing. On the other hand, a solution is a homogeneous mixture in which no settling occurs and in which the dissolved...
21.2K
Torque
22.6K
Torque is an important quantity for describing the dynamics of a rotating rigid body. We see the application of torque in many ways in the world, such as when pressing the accelerator in a car, which causes the engine to apply additional torque on the drivetrain. Here, we define torque and provide a framework to create an equation to calculate torque for a rigid body with fixed-axis rotation.
Torque can be considered as the rotational counterpart to force. Since forces change the translational...
Torque can be considered as the rotational counterpart to force. Since forces change the translational...
22.6K
Torque Free Motion
818
The torque-free motion refers to the movement of a rigid body in space when no external torques are acting upon it. This type of motion can be observed in environments where there are no external forces or frictions, like in outer space. For example, a rotation of Mars in space is a torque-free motion. Mars is an axisymmetric object, meaning it has an axis of symmetry along which it rotates, designated as the z-axis. The rotating frame of reference is defined such that the center of mass of...
818
Net Torque Calculations
11.6K
When a mechanic tries to remove a hex nut with a wrench, it is easier if the force is applied at the farthest end of the wrench handle. The lever arm is the distance from the pivot point (the hex nut in this case) to the person’s hand. If this distance is large, the torque is higher. Only the component of the force perpendicular to the lever arm contributes to the torque. Therefore, pushing the wrench perpendicular to the lever arm is more advantageous. If multiple people apply force to...
11.6K
Subatomic Particles
113.5K
Dalton was only partially correct about the particles that make up matter. All matter is composed of atoms, and atoms are composed of three smaller subatomic particles: protons, neutrons, and electrons. These three particles account for the mass and the charge of an atom.
113.5K
Colloids and Suspensions
3.5K
Children at play often make suspensions such as mixtures of mud and water, flour and water, or a suspension of solid pigments in water known as tempera paint. These suspensions are heterogeneous mixtures composed of relatively large particles visible to the naked eye or seen with a magnifying glass. They are cloudy, and the suspended particles settle out after mixing. The suspended particles in a suspension settle out after some time of mixing. The separation of particles from a suspension is...
3.5K

