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This study introduces a new continuum theory for active nematic gels, revealing how internal activity can drive spontaneous particle flow or self-organization into oppositely directed subchannels.

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Area of Science:

  • Soft matter physics
  • Continuum mechanics
  • Active matter physics

Background:

  • Active nematic gels are fluids with orientable rodlike objects exhibiting active dynamics.
  • Existing theories often introduce activity as an additional stress tensor term.
  • This work builds upon a recent theory for passive nematic liquid crystals.

Purpose of the Study:

  • To develop a continuum theory for active nematic gels.
  • To incorporate active dynamics through an external remodeling force.
  • To investigate the interplay between viscoelasticity and activity.

Main Methods:

  • Symmetry arguments and thermodynamic compatibility.
  • Modeling active nematic gels as relaxing nematic elastomers with active remodeling.
  • Analysis of a one-dimensional channel geometry.

Main Results:

  • Activity is introduced as an external remodeling force, not a stress tensor addition.
  • This force competes with passive relaxation, driving the system out of equilibrium.
  • Nonuniform nematic order and activity lead to spontaneous particle flow or self-organization into oppositely flowing subchannels.

Conclusions:

  • The proposed theory provides a novel framework for active nematic gels.
  • The external remodeling force concept offers a new perspective on active matter.
  • The findings demonstrate emergent collective behaviors like spontaneous flow and self-organization.