Colloids in active fluids: simulations of microrheology experiments
- Event time: 1:00pm
- Event date: 16th April 2012
- Speaker: Giulia Foffano (Formerly School of Physics & Astronomy, University of Edinburgh)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
Active fluids are suspensions of particles that absorb energy from their surroundings (or from an internal reservoir) in order to do work. They represent a novel type of out-of-equilibrium system and they are found predominantly, even though not solely, in biological contexts. I will present results concerning the simulation of an experiment in which a colloidal probe is pulled through an active nematic fluid and show that the drag on the particle is non-Stokesian (not proportional to its radius). I will explain this in terms of the disruption of orientational order around the probe particle and show how this leads to the prediction of a regime in which a large enough particle in contractile fluid (such as an actomyosin gel) can show negative viscous drag in steady state, which is confirmed in simulations.
This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..