Lubrication of Individual Microcontacts by a Self-Assembled Alkyl Phosphonic Acid Monolayer on α-Al2O3(0001)

Paul J, Meltzer C, Braunschweig B, Peukert W (2016)


Publication Language: English

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2016

Journal

Publisher: American Chemical Society

Book Volume: 32

Pages Range: 8298-8306

Journal Issue: 33

DOI: 10.1021/acs.langmuir.6b01933

Abstract

We report on the tribological behavior of a self-assembled alkyl phosphonic acid monolayer on the microscale using the colloidal probe technique. Friction-load data and adhesion forces were measured with borosilicate glass particles on uncoated and octadecylphosphonic acid (ODPA) coated α-AlO(0001) surfaces. A significant decrease in friction force was observed after surface coating, while the adhesion force was only moderately reduced. We assume the lubrication effect of the ODPA self-assembled monolayer (SAM) to be close to the maximum obtainable of alkyl phosphonic acids in the studied system due to the high molecular order which was confirmed by vibrational sum-frequency generation. At small loads, a nonlinear dependence of friction force to load was maintained after surface coating. However, a shift from a contact behavior well described by the DMT model toward the JKR model occurred that is possibly related to the altered elastic properties of the coated surface. With increasing load, a linear friction-load behavior was observed on the coated samples. Molecular plowing and adhesive interactions were identified as responsible mechanisms. In all friction experiments, we could not detect any wear neither of the colloidal probes nor at the surfaces of uncoated and coated samples. This proves the high wear resistivity of the studied ODPA SAM.

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APA:

Paul, J., Meltzer, C., Braunschweig, B., & Peukert, W. (2016). Lubrication of Individual Microcontacts by a Self-Assembled Alkyl Phosphonic Acid Monolayer on α-Al2O3(0001). Langmuir, 32(33), 8298-8306. https://dx.doi.org/10.1021/acs.langmuir.6b01933

MLA:

Paul, Jonas, et al. "Lubrication of Individual Microcontacts by a Self-Assembled Alkyl Phosphonic Acid Monolayer on α-Al2O3(0001)." Langmuir 32.33 (2016): 8298-8306.

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