Levich Institute Seminar Announcement, 09/07/2010
Steinman Hall, Room #312
(Chemical Engineering Conference Room)
Professor Pedro Reis
Massachusetts Institute of Technology
Civil and Environmental Engineering and Mechanical Engineering
"The Elasto-Pipette: Grabbing Water with Thin Elastic Sheets"
The study of the elasticity of thin objects (rods, plates and shells) is a rapidly burgeoning field. It is bringing together seemingly separate communities ranging from statistical physics to differential geometry, structural mechanics and nanotechnology. Recent work has shown that the strong non-linearities arising primarily from geometry are responsible for universal modes of deformation and singularities that are not material specific. Moreover, coupling the elasticity of thin objects with phenomena such as fracture, flow, surface tension, adhesion at solid interfaces raises new fundamental problems arising frequently in nature and technology. In this talk I will focus on the particular coupling of the elasticity of thin sheets and interfacial fluid forces. Inspired by real aquatic flowers, I shall present the results of a combined experimental and theoretical study of a system in which a thin petal-shaped plate is withdrawn from the flat interface of a liquid bath. As the flexible plate is drawn upwards, it deforms due to interfacial and hydrostatic forces, up to a point where it completely detaches from the interface as pinch-off occurs. If the bending stiffness of the plate is sufficiently low, upon detachment, a regime can be attained where the petal-shaped plate can fully enclose and therefore grab a drop from the liquid bath. We propose this mechanism as a robust means by which to grab, manipulate and transport small fluid droplets. This novel pipetting mechanism is passive and relies purely on the coupling of the elastic of thin plates and hydrodynamic forces at the interface.
BRIEF ACADEMIC/EMPLOYMENT HISTORY
RECENT RESEARCH INTERESTS
Mechanics of Materials, Elasticity of Thin Elastic Objects, Fracture, Adhesion, Solid Foams, Granular Materials, Non-equilibrium Statistical Mechanics.