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

Paper PS+BI-FrM2
Angle Resolved XPS Characterisation of Plasma Polymerised Chemical Gradients

Friday, November 19, 2004, 8:40 am, Room 213C

Session: Plasmas in Bioscience
Presenter: A. Wright, Thermo Electron Corporation, United Kingdom
Authors: K.L. Parry, Plasso Technology Ltd.
A.G. Shard, University of Sheffield, United Kingdom
R.G. White, Thermo Electron Corporation
J.D. Whittle, Plasso Technology Ltd.
A. Wright, Thermo Electron Corporation, United Kingdom
Correspondent: Click to Email
Well-defined chemical gradients are potentially important materials in a wide range of research activities. The surfaces of such materials can be derivatised with differing functional groups to provide spatially resolved surface chemical properties. Such surfaces can, for example, be used to immobilise biomolecules, which may become a route to producing novel biosensors. This study is concerned with chemical gradients within thin layers of plasma co-polymers deposited onto glass substrates. Continuous gradients of chemistry (hydrocarbon to either acid or amine) are produced by carefully programming the composition of the plasma monomer mixture while varying the area of the substrate exposed to the plasma. It will be shown that spatially resolved XPS is an ideal tool to determine the composition of the near surface region as a function of distance along the chemical gradient. Parallel angle resolved XPS provides additional information about the uniformity of the layer with depth. Such measurements can show, for example, surface enrichment of one of the functional groups in the co-polymer layer or variations in thickness along the chemical gradient. It is therefore possible to construct chemical state and thickness line scans or maps from the same ARXPS data set. Such data provide valuable information regarding the plasma co-polymer deposition process.