Simultaneous neutron reflectometry and infrared reflection absorption spectroscopy (IRRAS) study of mixed monolayer reactions at the air–water interface

Skoda, M. W.A., Thomas, B., Hagreen, M., Sebastiani, F. and Pfrang, C. (2017) Simultaneous neutron reflectometry and infrared reflection absorption spectroscopy (IRRAS) study of mixed monolayer reactions at the air–water interface. RSC Advances, 7 (54). pp. 34208-34214. ISSN 2046-2069 doi: 10.1039/c7ra04900e

Abstract/Summary

The simultaneous application of neutron reflectometry (NR) and infrared reflection absorption spectroscopy (IRRAS) to the study of the oxidation kinetics of organic monolayers at the air–water interface is described for the first time. This advance was possible thanks to the development of a new sample environment that includes a gas-delivery system and is compatible with in situ application of the two techniques within the constraints of short-term neutron beam-line access. We studied the oxidation of monolayers of the mono-molecular film palmitoleic acid and of a binary mixture of oleic (OA) and stearic (SA) acids by gas-phase ozone. We contrast the two highly complementary techniques and demonstrate that IRRAS provides key additional insight into the alignment of surfactant molecules at the air–water interface. We highlight the potential of the more economical and widely available IRRAS technique to complement NR studies. We also found an apparent increase of the NR signal upon oxidation of a mixed SA/OA monolayer, as well as evidence of slow intensity fluctuations of the SA- generated IRRAS signal. We demonstrate how simultaneous NR-IRRAS substantially enhances future studies of increasingly complex surfactant mixtures and their atmospheric surface reactions.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/71995
Identification Number/DOI	10.1039/c7ra04900e
Refereed	Yes
Divisions	Interdisciplinary centres and themes > Chemical Analysis Facility (CAF) Interdisciplinary Research Centres (IDRCs) > Walker Institute Life Sciences > School of Chemistry, Food and Pharmacy > Department of Chemistry Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Royal Society of Chemistry
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