Materzok, Tobias ; De Boer, Danna ; Gorb, Stanislav ; Müller‐Plathe, Florian (2024)
Gecko Adhesion on Flat and Rough Surfaces: Simulations with a Multi‐Scale Molecular Model.
In: Small : nano micro, 2022, 18 (35)
doi: 10.26083/tuprints-00022909
Artikel, Zweitveröffentlichung, Verlagsversion
 | Es ist eine neuere Version dieses Eintrags verfügbar. |
Kurzbeschreibung (Abstract)
A multiscale modeling approach is used to develop a particle‐based mesoscale gecko spatula model that is able to link atomistic simulations and mesoscale (0.44 µm) simulations. It is used to study the detachment of spatulae from flat as well as nanostructured surfaces. The spatula model is based on microscopical information about spatulae structure and on atomistic molecular simulation results. Target properties for the coarse‐graining result from a united‐atom model of gecko keratin in periodic boundary conditions (PBC), previously developed by the authors. Pull‐off forces necessary to detach gecko keratin under 2D PBC parallel to the surface are previously overestimated when only a small region of a spatula is examined. It is shown here that this is due to the restricted geometry (i.e., missing peel‐off mode) and not model parameters. The spatula model peels off when pulled away from a surface, both in the molecular picture of the pull‐off process and in the force‐extension curve of non‐equilibrium simulations mimicking single‐spatula detachment studied with atomic force microscopy equipment. The force field and spatula model can reproduce experimental pull‐off forces. Inspired by experimental results, the underlying mechanism that causes pull‐off forces to be at a minimum on surfaces of varying roughnesses is also investigated. A clear sigmoidal increase in the pull‐off force of spatulae with surface roughness shows that adhesion is determined by the ratio between spatula pad area and the area between surface peaks. Experiments showed a correlation with root‐mean‐square roughness of the surface, but the results of this work indicate that this is not a causality but depends on the area accessible.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2024 |
| Autor(en): | Materzok, Tobias ; De Boer, Danna ; Gorb, Stanislav ; Müller‐Plathe, Florian |
| Art des Eintrags: | Zweitveröffentlichung |
| Titel: | Gecko Adhesion on Flat and Rough Surfaces: Simulations with a Multi‐Scale Molecular Model |
| Sprache: | Englisch |
| Publikationsjahr: | 22 Januar 2024 |
| Ort: | Darmstadt |
| Publikationsdatum der Erstveröffentlichung: | 2022 |
| Ort der Erstveröffentlichung: | Weinheim |
| Verlag: | Wiley-VCH |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Small : nano micro |
| Jahrgang/Volume einer Zeitschrift: | 18 |
| (Heft-)Nummer: | 35 |
| Kollation: | 10 Seiten |
| DOI: | 10.26083/tuprints-00022909 |
| URL / URN: | https://tuprints.ulb.tu-darmstadt.de/22909 |
| Zugehörige Links: | |
| Herkunft: | Zweitveröffentlichung DeepGreen |
| Kurzbeschreibung (Abstract): | A multiscale modeling approach is used to develop a particle‐based mesoscale gecko spatula model that is able to link atomistic simulations and mesoscale (0.44 µm) simulations. It is used to study the detachment of spatulae from flat as well as nanostructured surfaces. The spatula model is based on microscopical information about spatulae structure and on atomistic molecular simulation results. Target properties for the coarse‐graining result from a united‐atom model of gecko keratin in periodic boundary conditions (PBC), previously developed by the authors. Pull‐off forces necessary to detach gecko keratin under 2D PBC parallel to the surface are previously overestimated when only a small region of a spatula is examined. It is shown here that this is due to the restricted geometry (i.e., missing peel‐off mode) and not model parameters. The spatula model peels off when pulled away from a surface, both in the molecular picture of the pull‐off process and in the force‐extension curve of non‐equilibrium simulations mimicking single‐spatula detachment studied with atomic force microscopy equipment. The force field and spatula model can reproduce experimental pull‐off forces. Inspired by experimental results, the underlying mechanism that causes pull‐off forces to be at a minimum on surfaces of varying roughnesses is also investigated. A clear sigmoidal increase in the pull‐off force of spatulae with surface roughness shows that adhesion is determined by the ratio between spatula pad area and the area between surface peaks. Experiments showed a correlation with root‐mean‐square roughness of the surface, but the results of this work indicate that this is not a causality but depends on the area accessible. |
| Freie Schlagworte: | gecko adhesion, molecular dynamics, multiscale molecular model, pull‐off force, roughness, spatula |
| ID-Nummer: | 2201674 |
| Status: | Verlagsversion |
| URN: | urn:nbn:de:tuda-tuprints-229090 |
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 530 Physik 500 Naturwissenschaften und Mathematik > 540 Chemie |
| Fachbereich(e)/-gebiet(e): | Profilbereiche Profilbereiche > Thermo-Fluids & Interfaces 07 Fachbereich Chemie 07 Fachbereich Chemie > Eduard Zintl-Institut > Fachgebiet Physikalische Chemie 07 Fachbereich Chemie > Theoretische Chemie (am 07.02.2024 umbenannt in Quantenchemie) |
| Hinterlegungsdatum: | 22 Jan 2024 13:42 |
| Letzte Änderung: | 23 Jan 2024 08:53 |
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| Suche nach Titel in: | TUfind oder in Google |
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- Gecko Adhesion on Flat and Rough Surfaces: Simulations with a Multi‐Scale Molecular Model. (deposited 22 Jan 2024 13:42) [Gegenwärtig angezeigt]
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