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Surface composition age analysis of photo-oxidized polystyrene thin films by X-ray photoelectron spectroscopy

ScholarsArchive at Oregon State University

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Title Surface composition age analysis of photo-oxidized polystyrene thin films by X-ray photoelectron spectroscopy
Names Silva, Nicholas A. (creator)
Líney Árnadóttir (advisor)
Date Issued 2015-05-28 (iso8601)
Note Honors Bachelor of Science (HBS)
Abstract Polystyrene thin film surfaces are commonly used to study the interactions of macromolecules, such as proteins, with surfaces. Polystyrene films oxidized in UV light become more hydrophilic, however these surfaces have a limited shelf life because they are reduced over time. Experiments were performed to determine the effect of radiation duration and exposure time on the surface composition of photo-oxidized polystyrene thin films. Polystyrene (2 wt%) in toluene was spin-coated onto 1-cm² monocrystalline silicon squares, and annealed at 70 °C for 18 hours. Three sets of triplicate samples were irradiated in a UV-ozone cleaner for 0, 3, and 9 minutes. Film surface compositions were analyzed via X-ray Photoelectron Spectroscopy 6 hours after irradiation and after one week of air exposure. Overall oxidation level decreased after one week, and the oxidation structure varied with irradiation time. It is speculated that decreases in oxidation level were due to surface contamination and reduction over time. Experimental results were inconclusive due to high levels of oxidative degradation and significant variation within sample sets. Future studies should shorten annealing and radiation exposure times to allow for improved contact angle measurement and lower degradation levels. More replicates or sample sets may further improve experimental outcomes.
Genre Thesis
Access Condition http://creativecommons.org/licenses/by-nc-nd/3.0/us/
Topic polystyrene
Identifier http://hdl.handle.net/1957/56211

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