Enhanced uptake of water by oxidatively processed oleic acid

Abstract

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 hydrogenbonded 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.

Atmospheric Aerosols: Composition, Transformation, Climate and Health Effects

“…[118][119][120][121][122][123][124][125][126][127][128] On the other hand, chemical aging of aerosol particles generally changes their composition, decreases their reactivity, increases their hygroscopicity and cloud condensation activity, and can change their optical properties. [19,114,115,[129][130][131][132][133][134] Because of their high surface-to-volume ratio, fine aerosol particles can be very efficiently transformed upon interaction with solar radiation (photolysis) and reactive trace gases (oxidation, nitration, acid-base reactions, hydrolysis, condensation or radical-initiated oligomerization, etc.). For example, oxidation and nitration reactions lead to the formation or degradation of hazardous aerosol components, [6,61,78,101] they cause artifacts upon collection and analysis of air particulate matter, [1,19,30] and they play a major role in technical processes and devices for the control of combustion aerosol emissions.…”

A new mechanism for ozonolysis of unsaturated organics on solids: phosphocholines on NaCl as a model for sea salt particles

“…11,12 An organic coating on sea salt particles is expected to modify the chemical and physical properties of the particles including their radiative properties. 8,[13][14][15][16] For example, it could affect the uptake of gases such as water, 17 altering both the gas and particle phases. Such effects on the particle properties may also change upon oxidation of the organic layer.…”

Unusual aggregates from the oxidation of alkene self-assembled monolayers: a previously unrecognized mechanism for SAM ozonolysis?

“…The C3 ¼ SAM showed similar behavior. Donaldson and coworkers 49 reported increased water uptake upon oxidation of oleic acid on quartz, and based on infrared spectroscopic measurements, proposed that polymerization had occurred. However, their films were prepared by spreading oleic acid on the surface using a cotton swab and were therefore more likely similar to the bulk material rather than a monolayer as was the case in the present studies.…”