Plasma is the fourth and most common state of matter, comprising more than 99,9 % of the visible universe. A plasma is composed of an ensemble of both charged and neutral particles and electromagnetic fields, having conducting properties and exhibiting collective effects.
Plasmas display a wide range of multiscale phenomena: in fact most plasma systems involve electrodynamics coupling across both micro and macro scale. Moreover plasma systems occur over most of the physically possible ranges in space, energy and density scales.
The figure here illustrates where many plasma systems occur in terms of typical density and energy conditions. However, the full range of possible plasma density, energy (temperature) and spatial scales go far beyond this illustration.
Plasmas produced in laboratories are shown in the illustration and they cover an energy range from 10-1-104 eV and a charged particle density from 108- 1020 (cm-3) [1,2]
» Plasma Processing
The use of plasma for surface modification of materials is becoming a real technology [3,4]. Plasma processing can be used for obtaining surfaces with specific desired properties, without affecting the bulk properties. Plasma treatment can induce chemical and physical changes of materials through activation, etching, grafting, film deposition, implantation, polymerisation and cross-linking processes. For example, plasma polymerization technique has been widely used in last years for surface modifications of material by deposition of functional thin films. For instance, organic thin films can be used as corrosion protective coatings, as passivating layers, as insulating components in electronic devices, as fluorescent films in optical devices. In the centre of excellence PLASMAPROMETEO different materials such as polymers, ceramics, textiles, lignocellulosic fibres, materials have been treated with plasma processes, in order to impart different surface properties.
» Further information is available in papers published in scientific and popular reviews:
Voice PLASMA, for the l’ Enciclopedia delle Scienze Fisiche (Edition TRECCANI),Vol. IV, authors: M.Fontanesi e C.Riccardi, p.517-523 (1993).
“Plasma? Il quarto stato della materia . il 99% del nostro universo (Plasma? The fourth state of the matter)”
C.Riccardi , Informazione Universitaria, Pubblicazione periodica del’i.s.u.,Universita’ degli Studi di Milano (University information) anno 4 n.2 , p.5 segue a p.15 (1998)
“Ricerche sperimentali sul trattamento dei tessuti con plasma freddi” (Experimental researches for textiles using cold plasma), C.Riccardi,
In the framework of a Seminar The Bicocca for industry: Plasma technological applications in the textile industry, University of Milano-Bicocca, 4 luglio 2000, Editors. Milano Ricerche, Milano and Larice.
“Trattamenti al plasma per i tessuti”, B.Marcandalli, C.Riccardi, M.Ardoino, Quaderni Assotec, vol. 2 (2001).