Adsorption, Contact, and Adhesion at Elastic and Capillary Interfaces

Seminar | January 16 | 4-5 p.m. | 120 Latimer Hall

 Joelle Frechette, Department of Chemical and Biomolecular Engineering, Johns Hopkins

 College of Chemistry

This presentation will first discuss the dynamic (and thermodynamics) of attachment of nanoparticles to fluid interfaces. We will look at the case where the nanoparticles are in dynamic equilibrium between the interface and a bulk phase and compare their adsorption to that of surfactants. We will demonstrate that the adsorption of nanoparticles competes with the attachment of amphiphilic ions from the bulk phase. Along with experimental results, we will present a model for the reversible adsorption of nanoparticles to oil-water interfaces that is based on a decrease in interfacial area and interaction between the particles. We show that the model describes well the equilibrium and dynamic conditions.

We will then discuss briefly discuss our efforts to understand how soft materials (elastomers, pressure sensitive adhesives) make contact and adhere under dynamic conditions in fluid environments. In particular, understanding and harnessing the coupling between lubrication pressure and elasticity provides materials design strategies for applications such as adhesives, coatings, microsensors, and biomaterials. We will discuss measurements of hydrodynamic interactions between soft surfaces. We will show how elastic films deform due to viscous forces and how these deformations are similar to those observed with fluid droplets. We will highlight implications for adhesion and soft lubrication and present results with pressure sensitive adhesives.

 Light refreshments will be served at 3:50 at The Coffee Lab, 510-643-0572