Enhanced uptake of water by oxidatively processed oleic acid A. Asad, B. T. Mmereki, and D. J. Donaldson Department of Chemistry and Department of Physical and Environmental Sciences, University of Toronto, 80 St. George St., Toronto, Ont. M5S 3H6, Canada
Abstract. A quartz crystal microbalance apparatus has been used to measure the room
temperature uptake of water vapour by thin films of oleic acid as a function
of relative humidity, both before and following exposure of the films to
various partial pressures of gas phase ozone. A rapid increase in the
water-sorbing ability of the film is observed as its exposure to ozone is
increased, followed by a plateau region in which additional water is taken
up more gradually. In this fully-processed region the mass of water taken up
by the film is about 4 times that of the unprocessed film. Infrared spectra
of the films, measured after variable exposures to ozone, show dramatic
increases in both the "free" and hydrogen-bonded O-H stretching regions,
and a decrease in the intensity of olefinic features. These results are
consistent with the formation of an oxygenated polymeric product or
products, as well as the gas phase products previously identified.
Citation: Asad, A., Mmereki, B. T., and Donaldson, D. J.: Enhanced uptake of water by oxidatively processed oleic acid, Atmos. Chem. Phys., 4, 2083-2089, doi:10.5194/acp-4-2083-2004, 2004.