Institut für Plasmaforschung der Universität Stuttgart

Research at Institute of Plasma Research (IPF) focuses on the physics of ionised gases and their applications, with their spectrum ranging from low-temperature plasmas for surface treatment with a view to industrial applications up to fusion plasmas for generation of environmentally friendly energy of the future. The "Plasma Technology" department at IPF deals with both low-pressure and atmospheric-pressure plasmas driven by microwaves at 2.45 GHz. Low-pressure plasmas are best qualified for customised surface treatment and deposition of thin films on different kinds of materials. As their thermal impact can be kept extremely low, plasma treatment performed on even heat-sensitive materials shows outstanding results.

Low-pressure plasmas are predominantly utilised for * customised modification of the surface properties on different kinds of materials (e.g., production of hydrophilic or hydrophobic surfaces, generation of locally different surface energy even on extremely small areas, etc.), * deposition of multi-functional coatings, barrier layers in particular (e.g., gas diffusion barriers, electrical insulation barriers, easy-to-clean coatings, etc.), * surface cleaning from organic residues in particular, with specific applications in medical engineering, and * sterilisation, particularly for applications in filling and packing of food as well as in medical and pharmaceutical industries.

Plasma sterilisation processes proved to be very efficient, particularly at low-pressure conditions, but also at atmospheric pressure: it is possible to inactivate microorganisms by at least four to five orders of magnitude within less than a second of plasma treatment time. Furthermore, plasma sterilisation does not rely on any dangerous or even toxic substances, and there is no need for any post-treatment as it is required for wet chemical processes, for example.
A miniaturised atmospheric-pressure plasma source presently in the development stage is designed for medical applications, e.g., specifically for treatment of septic wounds: radicals formed in the plasma are known to assist wound healing, and their interaction with UV light produced by the plasma will have an antimicrobial effect. In contrast to the cold plasma of this atmospheric micro-plasma source, temperatures of several thousands degrees Centigrade show to be in the core of the plasma produced by the so-called "Atmospheric Plasma System (APS)". This kind of atmospheric-pressure plasma source was developed particularly with regard to treatment of fluorinated and chlorinated hydrocarbons in waste gases.