High resolution AFM imaging of ion adsorption and charge distribution at heterogeneous clay mineral-liquid interfaces

Research output: Contribution to conferencePoster

Abstract

The solid-liquid interface and electrostatic interactions in solution is a quite complex topic. It is known for playing an extremely important role in determining molecular structure and binding activity, since almost all surfaces become charged by a variety of mechanisms when they come in contact with an aqueous medium. A typical picture with such a charged surface is that small ions of opposite sign accumulate in its immediate neighborhood, resulting in the formation of an electric double layer (EDL). Depending on the local solid-liquid and liquid-liquid molecular interactions, the interfacial liquid does not behave like a bulk liquid, often exhibiting higher densification and ordering that strongly depend on the local properties of the solid surface. However, experimental research remains challenging due to the lack of techniques offering sufficient resolution over inhomogeneous surfaces. Herein, unprecedented high resolution measurements of the ion adsorption and charge distribution on composite silicon oxide/gibbsite nanoplatelet surfaces using atomic force spectroscopy with sharp tips will be presented. FM-AFM spectroscopy results allow us to determine the local surface charge with a lateral resolution in the 10 nm range and to identify specific ion effects. Ultrahigh resolution AM-AFM images reflect the solvation structure of the interfacial liquid. Unlike Na+ and K+ ions, divalent ions like Ca2+ and Mg2+ modify and fully define the interface probed by AFM tip, consequently confirming their strong absorption to the surface
Original languageEnglish
Publication statusPublished - 22 Jul 2018
EventWater and Aqueous Solutions: Gordon Research Conference 2018: Water: Driving Life, Medicine, Energy and Environment - Holderness School, Holderness, United States
Duration: 22 Jul 201827 Jul 2018

Conference

ConferenceWater and Aqueous Solutions: Gordon Research Conference 2018
CountryUnited States
CityHolderness
Period22/07/1827/07/18

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Sîretanu, I., Klaassen, A. H., Ebeling, D., Andersson, M. P., Liu, F., van den Ende, H. T. M., & Mugele, F. G. (2018). High resolution AFM imaging of ion adsorption and charge distribution at heterogeneous clay mineral-liquid interfaces. Poster session presented at Water and Aqueous Solutions: Gordon Research Conference 2018, Holderness, United States.