Growing elastomeric stalactites on different substrate morphologies*

This work uses curable elastomers and the Rayleigh-Taylor (RT) instability to create stalactite-like structures. A thin film of elastomer is coated on a flat plate and is flipped to allow the formation of a lattice of drops on the underside of the plate. The drop separation on this plate is dictated by the RT instability. Once cured, this process is repeated to form another layer of elastomer, and so on. Elastomeric stalactites are observed as the number of coatings is increased. We also observed that from the second layer onwards, the structure seems to have two regimes - a uniform thin film regime and a pendant drop regime. This problem is studied both in a dynamic way, to look at the time dependence of the process and in a hydrostatic way, to look at the equilibrium profiles of stalactites formed.