Fall 2015

Seminars are held on Mondays from 2:30 - 3:30PM in Cullimore Hall, Room 611, unless noted otherwise. For questions about the seminar schedule, please contact David Shirokoff.


Date: September 21, 2015

Speaker: Carlos Colosqui
Department of Mechanical Engineering,
Stony Brook University

University Profile

Title: "Crossovers from Capillary-Driven to Thermally-Driven Wetting"

Abstract:

The spreading of droplets on solids, imbibition of porous media, and wicking of fabrics are wetting processes commonly assumed to be governed by hydrodynamic and capillary forces. To describe capillary forces, solid-fluid and fluid-fluid interfaces are typically modeled as smooth surfaces through the use of differential geometry. In addition, surface energies are often assumed to be constant or to exhibit a smooth spatial variation. A series of recent experimental observations have revealed significant limitations of these conventional approaches. In particular, the final relaxation to thermodynamic equilibrium appears to be determined by the interplay between Brownian motion and the nanoscale physicochemical structure of the solid-fluid interface. This talk will present recent experimental, theoretical, and computational studies of diverse systems that exhibit a remarkable crossover from regimes dominated by hydrodynamic and capillary forces to regimes governed by thermally-activated processes. Theoretical developments and empirical observations indicate specific combinations of “system-level” geometry and nanoscale surface structure that can dramatically modify the dynamics of diverse wetting processes and thus determine the effective wettability of a material.