2012/04/30 by G. Foffano, Juho S. Lintuvuori, J. S. Lintuvuori +6
Engineering · Materials Science · Physics and Astronomy · #Chemical engineering #Chemical physics #Classical mechanics #Colloid #Colloidal particle #Drag #Materials science #Mechanics #Micro and Nano Robotics #Microrheology #Nanotechnology #Particle Dynamics in Fluid Flows #Physics #Pickering emulsions and particle stabilization #Rheology #Thermodynamics #cond-mat.soft
paper · pdf · doi:10.1103/physrevlett.109.028103
5 pages, 3 figures
openalex publication_date 2012/07/11 · arxiv created 2012/09/03 · arxiv updated 2015/06/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We simulate an experiment in which a colloidal probe is pulled through an active nematic fluid. We find that the drag on the particle is non-stokesian (not proportional to its radius). Strikingly, a large enough particle in contractile fluid (such as an actomyosin gel) can show negative viscous drag in steady state: the particle moves in the opposite direction to the externally applied force. We explain this, and the qualitative trends seen in our simulations, in terms of the disruption of orientational order around the probe particle and the resulting modifications to the active stress.