title: Effect of Oxygen Chemistry in Sputtering of Polymers.
abstract: Molecular dynamics computer simulations are used to model kiloelectronvolt cluster bombardment of pure hydrocarbon [polyethylene (PE) and polystyrene (PS)] and oxygen-containing [paraformaldehyde (PFA) and polylactic acid (PLA)] polymers by 20 keV C60 projectiles at a 45° impact angle to investigate the chemical effect of oxygen in the substrate material on the sputtering process. The simulations demonstrate that the presence of oxygen enhances the formation of small molecules such as carbon monoxide, carbon dioxide, water, and various molecules containing C═O double bonds. The explanation for the enhanced small molecule formation is the stability of carbon and oxygen multiple bonds relative to multiple bonds with only carbon atoms. This chemistry is reflected in the fraction of the ejected material that has a mass not higher than 104 amu. For PFA and PLA, the fraction is approximately 90% of the total mass, whereas for PE and PS, it is less than half.
authors.affiliation: Smoluchowski Institute of Physics, Jagiellonian University , ul. Lojasiewicza 11, 30-348 Krakow, Poland.
authors.forename: Michal
authors.initials: M
authors.lastname: Kanski
authors.affiliation: Department of Chemistry, 104 Chemistry Building, Penn State University , University Park, Pennsylvania 16802, United States.
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Garrison
authors.affiliation: Smoluchowski Institute of Physics, Jagiellonian University , ul. Lojasiewicza 11, 30-348 Krakow, Poland.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Postawa