Rayleigh-Taylor mediated microstructures

We harness interfacial instabilities in thin liquid films and freeze them to spontaneously fabricate solid structures at the materials level. Specifically, we leverage the Rayleigh-Taylor instability in thin liquid elastomeric coatings to generate smooth microstructures with tailored geometrical properties, from drops lattices to flexible hairy elastic surfaces. A thin polymeric film is initially deposited onto a cylinder substrate which is then rotated so that its interface destabilizes under the action of the centrifugal acceleration. Drop lattices with wavelength ranging over three decades are simply obtained by modulating the magnitude of the acceleration field. By coating multiple times the surface of the rotating cylinder, we force the instability close to its most unstable mode. We show that after a few generations, the drops converge towards the same shape. Our method furthers our capacities in fast-prototyping complementing additive manufacturing and other conventional molding techniques.