Shear-Induced Gelation of Self-Yielding Active Networks.

Area of Science:

• Soft matter physics
• Biophysics
• Materials science

Background:

• Active materials offer control over bulk properties via microscopic components.
• Microtubule-based materials exhibit autonomous flows driven by internal dynamics.

Purpose of the Study:

• To investigate the relationship between microscopic dynamics and macroscopic rheological properties in 3D microtubule active materials.
• To understand how internal activity and external shear affect the viscosity of these nonequilibrium networks.

Main Methods:

• Utilized a combination of advanced microscopy and rheology techniques.
• Studied three-dimensional microtubule-based active materials.
• Quantified microscopic dynamics and bulk mechanical properties.

Main Results:

• Discovered a nonmonotonic viscosity dependence on the interplay between internal activity and applied shear.
• Observed that the material exhibits both solid-like and fluid-like behaviors.
• A simple two-state mechanical model successfully described the rheological measurements.

Conclusions:

• The rheological behavior of these active materials is tunable by balancing internal activity and external forces.
• The developed two-state model provides a predictive framework for active material rheology.
• Microscopic rearrangements are key to macroscopic flow and mechanical response in these systems.