Indentation and Self-Healing Mechanisms of a Self-Assembled Monolayer-A Combined Experimental and Modeling Study

Beitrag in einer Fachzeitschrift


Details zur Publikation

Autorinnen und Autoren: Meltzer C, Paul J, Dietrich H, Jäger C, Clark T, Zahn D, Braunschweig B, Peukert W
Zeitschrift: Journal of the American Chemical Society
Verlag: American Chemical Society
Jahr der Veröffentlichung: 2014
Band: 136
Heftnummer: 30
Seitenbereich: 10718--10727
ISSN: 1520-5126
Sprache: Englisch


Abstract


A combination of in situ vibrational sum-frequency generation (SFG) spectroscopy and molecular-dynamics (MD) simulations has allowed us to study the effects of indentation of self-assembled octadecylphosphonic acid (ODPA) monolayers on α-Al2O3(0001). Stress-induced changes in the vibrational signatures of C-H stretching vibrations in SFG spectra and the results of MD simulations provide clear evidence for an increase in gauche-defect density in the monolayer as a response to indentation. A stress-dependent analysis indicates that the defect density reaches saturation at approximately 155 MPa. After stress is released, the MD simulations show an almost instantaneous healing of pressure-induced defects in good agreement with experimental results. The lateral extent of the contact areas was studied with colocalized SFG spectroscopy and compared to theoretical predictions for pressure gradients from Hertzian contact theory. SFG experiments reveal a gradual increase in gauche-defect density with pressure before saturation close to the contact center. Furthermore, our MD simulations show a spatial anisotropy of pressure-induced effects within ODPA domains: molecules tilted in the direction of the pressure gradient increase in tilt angle while those on the opposite side form gauche-defects.



FAU-Autorinnen und Autoren / FAU-Herausgeberinnen und Herausgeber

Braunschweig, Björn Dr.
Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik
Clark, Timothy apl. Prof. Dr.
Computer-Chemie-Centrum
Dietrich, Hanno
Computer-Chemie-Centrum
Jäger, Christof Dr.
Computer-Chemie-Centrum
Meltzer, Christian
Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik
Paul, Jonas
Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik
Peukert, Wolfgang Prof. Dr.-Ing.
Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik
Zahn, Dirk Prof. Dr.
Professur für Theoretische Chemie


Zusätzliche Organisationseinheit(en)
Exzellenz-Cluster Engineering of Advanced Materials
Graduiertenkolleg 1896/2 In situ Mikroskopie mit Elektronen, Röntgenstrahlen und Rastersonden
Interdisziplinäres Zentrum, Center for Nanoanalysis and Electron Microscopy (CENEM)


Forschungsbereiche

A1 Functional Particle Systems
Exzellenz-Cluster Engineering of Advanced Materials
A3 Multiscale Modeling and Simulation
Exzellenz-Cluster Engineering of Advanced Materials


Zitierweisen

APA:
Meltzer, C., Paul, J., Dietrich, H., Jäger, C., Clark, T., Zahn, D.,... Peukert, W. (2014). Indentation and Self-Healing Mechanisms of a Self-Assembled Monolayer-A Combined Experimental and Modeling Study. Journal of the American Chemical Society, 136(30), 10718--10727. https://dx.doi.org/10.1021/ja5048076

MLA:
Meltzer, Christian, et al. "Indentation and Self-Healing Mechanisms of a Self-Assembled Monolayer-A Combined Experimental and Modeling Study." Journal of the American Chemical Society 136.30 (2014): 10718--10727.

BibTeX: 

Zuletzt aktualisiert 2019-03-06 um 17:09