Ozone oxidation of self-assembled monolayers on silicon oxide thin layers on silicon and zinc selenide surfaces

COLL 272

Olivia Ryder, oryder@uci.edu1, Theresa M. McIntire, mcintire@uci.edu1, A. S. Lea2, Paul L. Gassman2, and Barbara J. Finlayson-Pitts, bjfinlay@uci.edu1. (1) Department of Chemistry, University of California, 1102 Natural Science 2, Irvine, CA 92697-2025, (2) Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, M/S K8-93, PO Box 999, Richland, WA 99352
Organic-coated airborne particles are important in atmospheric chemistry. However, the nature and reactivity of such particles are largely uncertain. Both the SiOx layer on silicon and SiO2-coated zinc selenide provide models of environmentally relevant surfaces, such as dust particles, upon which organics adsorb. Formation of thin films of unsaturated alkene self-assembled monolayers (SAMs) on these substrates mimic reactive organics on airborne dust. Previous ozonolysis studies of the SAMs showed the formation of carbonyl groups and micron-sized, hydrophobic organic aggregates surrounded by carbon depleted substrate. Recent ATR-FTIR studies of the oxidation of alkene SAMs on SiO2-coated ZnSe provide a broader spectral window. These studies show that the loss of C=C and formation of carbonyl groups is also accompanied by formation of a peak at 1110 cm-1, attributed to the secondary ozonide. Details concerning the products and mechanism of ozonolysis of alkene SAMs on surfaces based on these new data are presented.
 

The Physical Chemistry of Environmental Interfaces
6:00 PM-8:00 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 244/245, Poster

Division of Colloid & Surface Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008