Molecular Foundry Seminar

"At the interface: complex liquid organization and ionic effects"

Kislon Voitchovsky, EPFL
Tuesday, January 24th @ 1:00 pm, Bldg. 67 - 3111

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Invited by Paul Ashby and the Imaging and Manipulation Facility

Abstract:

At the interface with solids, liquid molecules tend to adopt a particular structural arrangement, which depends on the local solid-liquid and liquid-liquid molecular interactions. As a result, this interfacial liquid does not behave like bulk liquid, often exhibiting higher densification and ordering that strongly depend on the local properties of the solid surface. This particular nature of the interfacial liquid is central to many phenomena from the folding and function of biomolecules to heterogeneous catalysis, adsorption phenomena, crystal growth, self-assembly and heat transfers.

Experimentally, probing the local structure and properties of interfacial liquid remains challenging due to the lack of techniques offering sufficient resolution over inhomogeneous surfaces. To overcome these difficulties we developed an approach based on amplitude-modulation atomic force microscopy (AM-AFM). I will show that when operated in a particular regime, AM-AFM can be used to probe and quantify solid-liquid interfaces locally and with sub-nanometer resolution. I will present several applications of the techniques as well as some comparative investigations of interfaces involving different liquids and a same solid. Finally, I will discuss some recent results where ionic effects modify or even fully define the interface probed by AFM.