Related Experiment Video
Updated: Jul 19, 2025
08:37
Forming, Confining, and Observing Microtubule-Based Active Nematics
Published on: January 13, 2023
2.7K
Friction-mediated phase transition in confined active nematics
Cody D Schimming1, C J O Reichhardt1, C Reichhardt1
1Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Physical Review. E
|August 16, 2023
Summary
Substrate friction and circular confinement in active nematics drive a phase transition. Increasing friction changes flow from circulating to anisotropic, controllable by boundary conditions.
Area of Science:
- Soft Matter Physics
- Nonlinear Dynamics
- Materials Science
Background:
- Active nematics are complex fluids with self-propelled constituents.
- Understanding their behavior under confinement and friction is crucial for designing novel materials.
- Previous studies often focused on unconfined systems or simpler boundary conditions.
Purpose of the Study:
- To investigate the combined effects of circular confinement and substrate friction on active nematic dynamics.
- To identify and characterize phase transitions induced by varying friction levels.
- To explore the control offered by boundary conditions on active nematic flow patterns.
Main Methods:
- Utilized a minimal continuum model for active nematics.
- Simulated systems with varying degrees of circular confinement.
- Systematically increased substrate friction from low to high levels.
Main Results:
- Observed a dynamical phase transition from a circulating flow to an anisotropic flow phase with increasing friction.
- The anisotropic flow phase exhibits flow perpendicular to the nematic director at the boundary.
- Flow structure and dynamic correlations differ from unconfined turbulent systems and are tunable via boundary conditions.
Conclusions:
- Substrate friction and geometric confinement are significant control parameters for active nematics.
- The interplay between confinement and friction enables novel dynamic regimes.
- Boundary conditions offer a pathway to engineer active nematic behavior.
Related Concept Videos
02:39Phase Transitions: Melting and Freezing
12.5K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
12.5K
02:31Phase Transitions
19.2K
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to...
19.2K
01:27Types of Friction Problems
566
Friction is an essential concept in physics, engineering, and everyday life. It is the force that opposes the relative motion or tendency of such motion between two surfaces in contact. One of the most common types of friction encountered in various applications is dry friction. Dry friction problems can be broadly categorized into three types, each with unique characteristics and challenges.
The first type of dry friction problem involves situations where there is no apparent impending motion....
The first type of dry friction problem involves situations where there is no apparent impending motion....
566
01:07Frictional Force
8.1K
When a body is in motion, it encounters resistance because the body interacts with its surroundings. This resistance is known as friction, a common yet complex force whose behavior is still not completely understood. Friction opposes relative motion between systems in contact, but also allows us to move. Friction arises in part due to the roughness of surfaces in contact. For one object to move along a surface, it must rise to where the peaks of the surface can skip along the bottom of the...
8.1K
01:05Static and Kinetic Frictional Force
16.0K
One of the simpler characteristics of sliding friction is that it is parallel to the contact surfaces between systems, and is always in a direction that opposes the motion or attempted motion of the systems relative to each other. If two systems are in contact and moving relative to one another, then the friction between them is called kinetic friction. For example, kinetic friction slows a hockey puck sliding on ice.
However, if two systems are in contact and are stationary relative to one...
However, if two systems are in contact and are stationary relative to one...
16.0K
02:33Phase Transitions: Sublimation and Deposition
17.2K
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
17.2K