Study of the Plasma Treatment of Polymeric Surfaces

A project financed by the Research Committee of the University of Patras

Our study focuses on the interaction between the surface and discharge produced species, like positive ions, UV photons and metastables, that have enough energy to result in chain scission, abstraction of surface groups and cross-linking. As a result of this treatment surface properties like wettability, roughness, adhesivity, chemical nature etc. These properties depend of course on various treatment conditions among which the nature of the discharge gas is of primary importance. The modified polymeric surfaces have various technological applications such as: modification or improvement of their hydrophilic or hydrophobic character, dyeability, biocompatibility etc. Materials having these features are widely used in the automobile industry, in food packaging, for biomaterials manufacturing and in microelectronics.

The Karatheodoris project is mainly focused on the study of the interaction between inert and reactive gases like Helium and Oxygen with polymers like Polyethylene Terephthalate and Polyethylene aiming to understand the basic process mechanisms and especially to elucidate the role of each of the active discharge species (ions, UV photons, metastables). For this purpose we apply several diagnostic techniques like RF Power and Impedance measurements, Laser Reflectance Interferometry for the measurement of the polymer etching rates, Mass Spectrometry and Spatially Resolved OES for the identification of the nature and effects of surface abstracted species .

Some of our very encouraging first results. were published so far in the following journal and conference proceedings:

1. "Application of Optical and Electrical Diagnostics during the treatment of PET films in a Helium glow discharge". D. Papakonstantinou, F. Arefi-Khonsari, D. Mataras and D. Rapakoulias, in proceedings of the 14th ISPC, vol. IV p. 1865-1869 Prague, Czech Republic 1999.

2. "Ion etching of Polyethylene Terephthalate films in helium glow discharges". D. Papakonstantinou and D. Mataras, in proceedings of the 15th ISPC, vol. VI p. 2421-2426, Orleans, France 2001.

3. "Treatment of Polyethylene Terephthalate in a Helium glow-discharge". D-D. Papakonstantinou, D. Mataras. J. Phys. IV. 11, Pr3-357 (2001). 

A couple of papers are in preparation and are expected to appear by the end of 2002.