Tuning the viscosity and jamming point in dense active non-Brownian suspensions

Area of Science:

• Physics
• Materials Science
• Rheology

Background:

• Dense suspensions of non-Brownian particles exhibit complex rheological behaviors.
• Active particles introduce self-propulsion, altering inter-particle interactions and bulk properties.

Purpose of the Study:

• Investigate the rheology of dense, frictional, non-Brownian suspensions with active particles.
• Determine how particle activity influences viscosity and shear jamming.
• Identify microscopic mechanisms governing these changes.

Main Methods:

• Utilized particle-based simulations to model suspension behavior.
• Varied activity strength of active particles as a key parameter.
• Analyzed frictional contacts and force-chain network evolution.

Main Results:

• Suspension viscosity and shear jamming point are tunable via active particle strength.
• Activity influences viscosity through changes in frictional contacts and force-chain isotropy.
• An effective temperature, derived from active particle parameters, governs viscosity.

Conclusions:

• Particle activity modulates suspension rheology by affecting jamming and force networks.
• Effective temperature provides a unified parameter for viscosity control.
• Overcoming jamming requires higher activity than preventing it.