TY  - JOUR
AU  - Creutzburg, Marcus
AU  - Konuk, Mine
AU  - Tober, Steffen
AU  - Chung, Simon
AU  - Arndt, Bjoern
AU  - Noei, Heshmat
AU  - Meissner, Robert
AU  - Stierle, Andreas
TI  - Adsorption of Oleic Acid on Magnetite Facets
JO  - Communications chemistry
VL  - 5
SN  - 2399-3669
CY  - [London]
PB  - Macmillan Publishers Limited, part of Springer Nature
M1  - PUBDB-2022-05102
SP  - 134
PY  - 2022
AB  - The microscopic understanding of the atomic structure and interaction at carboxylic acid/oxide interfaces is an important step towards tailoring the mechanical properties of nanocomposite materials assembled from metal oxide nanoparticles functionalized by organic molecules. We have studied the adsorption of oleic acid (C<sub>17</sub>H<sub>33</sub>COOH) on the most prominent magnetite (001) and (111) crystal facets at room temperature using low energy electron diffraction, surface X-ray diffraction and infrared vibrational spectroscopy complemented with molecular dynamics simulations used to infer specific hydrogen bonding motifs between oleic acid and oleate. Our experimental and theoretical results give evidence that oleic acid adsorbs dissociatively on both facets at lower coverages. At higher coverages, the more pronounced molecular adsorption causes hydrogen bond formation between the carboxylic groups, leading to a more upright orientation of the molecules on the (111) facet in conjunction with the formation of a denser layer, as compared to the (001) facet. This is evidenced by the C=O double bond infrared line shape, in depth molecular dynamics bond angle orientation and hydrogen bond analysis, as well as X-ray reflectivity layer electron density profile determination. Such a higher density can explain the higher mechanical strength of nanocomposite materials based on magnetite nanoparticles with larger (111) facets.
LB  - PUB:(DE-HGF)16
C6  - 36697717
UR  - <Go to ISI:>//WOS:000871217600001
DO  - DOI:10.1038/s42004-022-00741-0
UR  - https://bib-pubdb1.desy.de/record/483080
ER  -