Levich Institute Seminar
Tue, Apr 30
2:00 PM — 3:15 PM
Steinman Hall160 Convent Avenue
Steinman Hall, 312
Professor Anand Jagota SeminarTITLE: "Surface Tension of Soft Solids "
ABSTRACT: The influence of surface tension in solids, as determined by the deformation it causes, typically acts over a length scale given by the ratio of surface tension and elastic modulus, an elastocapillary length. For conventional, relatively stiff solids, with elastic modulus in the range of several MPa or larger, this elastocapillary length is a few nanometers or smaller, and phenomena caused by surface tension manifest only at rather small length scales. However, for soft or compliant solids, such as hydrogels and compliant elastomers, solid surface tension can drive relatively large deformation and probably has a pervasive, but little studied, influence. We will discuss experiments on flattening of an undulating gel surface and a film-terminated elastomeric structure where surface tension drives easily measured deformation. We will also present results of experiments in which a liquid drop placed on a compliant film causes it to deform into a shape analogous to Neumann's triangle in which the tension in the solid-fluid interfaces plays an important role. Experiments are complemented by theoretical and computational analyses of surface-tension-drive deformation. Finally, we will discuss how a difference between surface tension and energy, which a solid material can sustain for some time, results in a chemical potential that can drive transport to or from the interface.