AVS 56th International Symposium & Exhibition
    Plasma Science and Technology Thursday Sessions
       Session PS1-ThM

Paper PS1-ThM12
Surface Properties of Plasma Treated Metal Oxides

Thursday, November 12, 2009, 11:40 am, Room A1

Session: Applications of Plasma-Surface Interactions
Presenter: K. Trevino, Colorado State University
Authors: K. Trevino, Colorado State University
E.R. Fisher, Colorado State University
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Metal oxides are used for various applications including polymer adhesion, anticorrosive coatings, and catalysis. Plasma treatments have proven useful in tailoring the properties of such surfaces due to their ease of use and environmental friendliness. However, the interfacial interactions that give rise to changes in surface charge and acid/base character are poorly understood. Measurement of these properties, along with surface characterization, allows for a clearer understanding of the important chemical processes. Of particular concern is the permanency of the surface treatment, which is expected to depend on plasma type, plasma conditions, substrate, and the position of the substrate in the plasma. In this work, we have separately treated SiOxNy surfaces with three non-polymerizing gases (Ar, H2O, and NH3) and monitored surface properties as a function of plasma parameters and substrate position for a period of thirty days. Surface charge and acid/base character were measured by determination of the isoelectric point (IEP) from contact angle titration data; surface composition and morphology were also taken and analyzed by XPS and SEM. Ar-plasma treatments yielded initial IEP values of ~7, however these values are not stable over time. In contrast, IEP values for H2O plasma treatments also increased (compared to an untreated substrate) to ~6, but stay relatively stable with age. Compositional data reveal information about the effectiveness of the treatments, and IEP data highlight the similarities and differences between the plasma systems. Results from additional metal oxides and polymer surfaces will also be presented and comparisons between systems will be made.