Visualization of Ion|Surface Binding and In Situ Evaluation of Surface Interaction Free Energies via Competitive Adsorption Isotherms.
| Autor: | Bilotto P; Institute of Applied Physics, Applied Interface Physics, Vienna University of Technology, 1040 Vienna, Austria., Imre AM; Institute of Applied Physics, Applied Interface Physics, Vienna University of Technology, 1040 Vienna, Austria., Dworschak D; Institute of Applied Physics, Applied Interface Physics, Vienna University of Technology, 1040 Vienna, Austria., Mears LLE; Institute of Applied Physics, Applied Interface Physics, Vienna University of Technology, 1040 Vienna, Austria., Valtiner M; Institute of Applied Physics, Applied Interface Physics, Vienna University of Technology, 1040 Vienna, Austria. |
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| Jazyk: | angličtina |
| Zdroj: | ACS Physical Chemistry Au [ACS Phys Chem Au] 2021 Nov 24; Vol. 1 (1), pp. 45-53. Date of Electronic Publication: 2021 Aug 23. |
| DOI: | 10.1021/acsphyschemau.1c00012 |
| Abstrakt: | Function and properties at biologic as well as technological interfaces are controlled by a complex and concerted competition of specific and unspecific binding with ions and water in the electrolyte. It is not possible to date to directly estimate by experiment the interfacial binding energies of involved species in a consistent approach, thus limiting our understanding of how interactions in complex (physiologic) media are moderated. Here, we employ a model system utilizing polymers with end grafted amines interacting with a negatively charged mica surface. We measure interaction forces as a function of the molecule density and ion concentration in NaCl solutions. The measured adhesion decreases by about 90%, from 0.01 to 1 M electrolyte concentration. We further demonstrate by molecular resolution imaging how ions increasingly populate the binding surface at elevated concentrations, and are effectively competing with the functional group for a binding site. We demonstrate that a competing Langmuir isotherm model can describe this concentration-dependent competition. Further, based on this model we can quantitatively estimate ion binding energies, as well as binding energy relationships at a complex solid|liquid interface. Our approach enables the extraction of thermodynamic interaction energies and kinetic parameters of ionic species during monolayer level interactions at a solid|liquid interface, which to-date is impossible with other techniques. Competing Interests: The authors declare no competing financial interest. (© 2021 The Authors. Published by American Chemical Society.) |
| Databáze: | MEDLINE |
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