Large-deformation dynamics of an elastic filament at a fluid interface

We study the dynamics of a thin elastic filament at the interface of two fluids and observe the time evolution in its shape when released from an initial configuration with a large curvature. The unfolding of the filament is driven by a competition between bending energy and viscous dissipation. We experimentally study the overdamped regime of this system by varying fluid viscosity ($\eta$), length ($L$), diameter ($d$) and elastic modulus ($E$) of the filament with similar initial conditions and observe the kinematics of the filament straightening. The time-dependence for this process can be collapsed by scaling time by $\eta L^4/Ed^3$. However, the characteristic time is a very small fraction of this time-scale. We perform numerical computations parallel to the experiments to get access to the dynamics of the filament to resolve this puzzle. An understanding of the time-dependence will enable the use of this technique to measure interfacial properties.