Self-Assembled Monolayers Get Their Final Finish via a Quasi-Langmuir-Blodgett Transfer

Meltzer C, Dietrich H, Zahn D, Peukert W, Braunschweig B (2015)

Publication Language: English

Publication Type: Journal article, Original article

Publication year: 2015

Journal

Langmuir American Chemical Society

Pages Range: n/a

Issue: n/a

Journal Issue: n/a

DOI: 10.1021/acs.langmuir.5b00440

Abstract

The growth of self-assembled monolayers (SAMs) of octadecylphosphonic acid (ODPA) molecules on α-Al2O3(0001) and subsequent dewetting of the SAMs were studied with a combination of in situ sum-frequency generation (SFG) and molecular dynamics (MD) simulations. Although SAM growth after deposition times >8 h reduces to nearly negligible values, the resultant ODPA SAMs in solution are still not in a well-ordered state with the alkyl chains in all-trans configurations. In fact, in situ SFG spectroscopy revealed a comparatively high concentration of gauche defects of the SAM in the ODPA 2-propanol solution even after a growth time of 16 h. Here, results of the MD simulations strongly suggest that defects can be caused by ODPA molecules which are not attached to the substrate but are incorporated into the SAM layer with the polar headgroup oriented into the 2-propanol solvent. This inverted adsorption geometry of additional ODPA molecules blocks adsorption sites and thus stabilizes the SAM without improving ordering to an extent that all molecules are in the all-trans configuration. While persistent in solution, the observed defects can be healed out when the SAMs are transferred from the solvent to a gas phase. During this process, a quasi-Langmuir-Blodgett transfer of molecules takes place which drives the SAM into a higher conformational state and significantly improves its quality.

Authors with CRIS profile

Christian Meltzer Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik Hanno Dietrich Lehrstuhl für Theoretische Chemie Dirk Zahn Professur für Theoretische Chemie Wolfgang Peukert Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik Björn Braunschweig Lehrstuhl für Feststoff- und Grenzflächenverfahrenstechnik

Additional Organisation(s)

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

How to cite

APA:

Meltzer, C., Dietrich, H., Zahn, D., Peukert, W., & Braunschweig, B. (2015). Self-Assembled Monolayers Get Their Final Finish via a Quasi-Langmuir-Blodgett Transfer. Langmuir, n/a, n/a. https://dx.doi.org/10.1021/acs.langmuir.5b00440

MLA:

Meltzer, Christian, et al. "Self-Assembled Monolayers Get Their Final Finish via a Quasi-Langmuir-Blodgett Transfer." Langmuir n/a (2015): n/a.

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