The wonders of thin sheets: From torn tape and sinking flowers to graphene ribbons and grabbing water
Pedro Reis , Professor of Civil and Environmental Engineering and Mechanical Engineering at MIT
| When: | Sep 01, 2010 | 4:00 pm - 5:00 pm |
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| Where: | Pierce 209 |
The reviving study of thin elasticity objects is a rapidly burgeoning field that is bringing together seemingly separate communities. Recent work has shown that the strong non-linearities arising primarily from geometry are responsible for universal modes of deformation. Moreover, coupling the elasticity of thin objects with phenomena such as fracture, interfacial forces and flow opens new fundamental problems arising frequently in technology and nature.
In this talk I will present three instances of the coupling of thin elastic sheets with adhesive forces at solid and liquid interfaces. First, I will discuss the annoying quotidian problem of torn adhesive tape which produces triangular flaps. Understanding this mechanism enables us to fabricate tapered graphene ribbons from an adhesive substrate, albeit at the nanoscale. The final example is inspired by sinking aquatic flowers. Reversing the process, as a flexible petal-shaped object is withdrawn from the interface of a liquid bath, it can close, pinch-off and thereby grab a droplet of liquid. We propose this as a novel passive pipetting mechanism that relies purely on the coupling of the elasticity of thin plates and the hydrodynamic forces at the liquid interface.
| Speaker Biography: | Ester and Harold E. Edgerton Assistant Professor of Civil and Environmental Engineering and Mechanical Engineering |
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| Host: | Katia Bertoldi |
| Contact: |
LaShanda Banks
lbanks@seas.harvard.edu 617-496-1461 |
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