Folding Flakes: the sedimentation of thin elastic sheets in a viscous fluid

There is much current interest in so-called two-dimensional materials because of their unusual and attractive mechanical and electrical properties. Much of their processing is performed in a fluid environment, e.g., during the size selection of dispersed graphene flakes by centrifugation, or their deposition by ink-jet printing. The flakes' large aspect ratio
implies that despite their impressive in-plane stiffness they have a very small bending stiffness and are therefore easily deformed by the traction that the surrounding fluid exerts on them. The resulting strong fluid-structure interaction affects not only the dynamics of individual flakes but also their collective behaviour.

The aim of this project is to perform a systematic theoretical/computational study of the behaviour of thin elastic sheets in a viscous fluid. Specifically, we wish to establish how the flow-induced deformation affects the sedimentation of such sheets, paying particular attention to the effect of wrinkling instabilities and the development of symmetry-breaking frustrated patterns: how do they arise in sheets of canonical shapes (circular, rectangular, polygonal,...) and how do they affect the sheets' sedimentation?