AVS 51st International Symposium
    Plasma Science and Technology Friday Sessions
       Session PS+BI-FrM

Paper PS+BI-FrM1
X-Ray and Neutron Reflectivity Studies of Plasma Polymer Coatings

Friday, November 19, 2004, 8:20 am, Room 213C

Session: Plasmas in Bioscience
Presenter: K.M. McLean, CSIRO Molecular Science, Australia
Authors: S.K. Øiseth,
P.G. Hartley, CSIRO Molecular Science, Australia
K.M. McLean, CSIRO Molecular Science, Australia
A Nelson, Bragg Institute, Australia
M James, Bragg Institute, Australia
Correspondent: Click to Email
Plasma polymer coatings adhere to and contour the surfaces of most organic and inorganic materials, and are attractive as surface chemical modification systems, since they offer both robustness and inherent surface chemical functionality for further surface chemical derivatisation. A variety of different techniques have been used to characterise the physico-chemical properties of surfaces of plasma polymer films. In many cases, however, it is also desirable to probe the internal structure of both modified and unmodified plasma polymer coatings in order to optimise their properties for a given application.. Reflectometry techniques are now becoming increasingly important in the characterization of nano-scale structured interfaces. X-ray reflectivity in particular is ideally suited to the study of the internal properties of layered film structures on surfaces, yielding data concerning sub surface structure and material properties. Neutron reflectivity meanwhile offers the ability to characterise surface layers in aqueous environments. In this study heptylamine and allylamine plasma polymer coatings were prepared on silicon wafers, and analysed using X-ray reflectometry before and after further surface modification procedures (e.g. adsorption of protein species from solution). Surface chemistry of the coatings was characterised using X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) was also used to characterise both roughness and local film thickness at step-edges on the films. The excellent reflectivity data obtained demonstrate the suitability of plasma polymers for reflectivity studies (primarily due to their low surface roughness). Preliminary experiments on plasma polymer layers using neutron reflectivity are also described, which highlight the effect of surface hydration on layer properties.