Fluor polymers, better known as Teflon, can be used in a variety of applications, but they have one serious drawback: they are extremely slippery. This is an advantage in pots and pans, but a problem for science and research. Be it component, pigment or glue- nothing sticks to this material. However, to the chagrin of cooks everywhere, Teflon can now be made to stick.
With the financial assistance of the Austrian Science Fund (FWF), Johannes Heitz from the Johannes Kepler University in Linz has developed a new method, in which laser radiation is used to modify Teflon surfaces and make them sticky.
Everyone knows Teflon and appreciates its benefits. The fields of application range from coatings on frying pans, electrical insulation layers, sliding surfaces and medical inserts to water-repellent textiles. The great advantage of this material is its low chemical reactivity and the extremely low adhesion of liquids to Teflon coatings.
But this advantage is also its greatest disadvantage. It has not been possible to modify small, specified areas on fluor polymer surfaces in such a way that glues or metallic coatings stick to them. This circumstance has limited the use of Teflon substrates in microelectronics, where strong adhesion of contacts is required, or in medical engineering.
Heinz achieved the desired effect by irradiating the surface of fluor polymers with UV light of extremely low wavelength, so-called vacuum UV light (172 nm): ‘The material is modified only in those places where it will be glued or coated. Until now, such modifications were possible only on large surface areas.
The chemical reaction takes place only on the surface and the Teflon retains its major property, namely its extremely low adhesion’. The modified materials combine the new surface properties with the desired characteristics of the unmodified residual material, such as excellent electrical insulation for electronics applications, or resistance to aggressive chemicals, or thermal stability. This is of special advantage in medical engineering, where the application of UV irradiated fluor polymers significantly facilitates the use of artificial blood vessels, grafts, cardiac valves or artificial skin.
The new technology ensures tissue adhesion and compatibility on the outer surface, while preventing the blood from clotting on the inner surface. The method is also interesting for the textile industry and the microelectronics industry, where excellent adhesion of metallic objects and contacts is a major prerequisite for any material.
Contact: Prof. Dr. Johannes Heitz Institute for Experimental Physics, Johannes Kepler University, Linz.
Tel.: +43 732 2468 924