Advanced Cold Plasma Synthesis of Organic Networks and Molecules

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Cold, non-equilibrium plasmas are created when a sufficiently high electrical potential is applied to a gas, causing its partial ionization. The associated electrical field transfer energy to the freed electrons, generating “hot” energetic electrons while the unaffected neutral molecules, which constitute the majority of the gas, maintain an average temperature close to ambient. This unique environment allows to trigger chemical reactions having high activation energies, which are generally unachievable around room temperature, without the associated effects of high temperatures, such as melting and carbonization. Cold plasmas have found applications in key technological areas, the main ones being lighting (fluorescent tubes) and microelectronics where they are used for deposition and etching of material layers that constitute electronic chips. Another key field where cold plasmas have found important applications is surface engineering where cold plasmas are used to alter to surface properties of materials to render them suitable for given applications. A common application is to use an atmospheric pressure corona discharge to improve the wetting of polymer films before printing in order to allow inks to adhere properly to the plastic. Another application, at the other end of the added value spectrum, is the surface engineering of biomedical implants to favour their incorporation in the body. Recently, direct interactions between cold plasma and liquids for destruction or synthesis of molecules as well as for direct medical applications has been a new and rapidly expanding research area. ***This proposal presents a research program aimed at developing cold plasma methods for the synthesis of organic molecules and networks – macromolecules with a mainly random structure - both as thin films, from the gas phase, and directly in liquids. The proposed program presents a comprehensive approach with developments in reactor and source design, characterization methods, fundamental studies and application oriented developments. A significant portion of the program is dedicated to surface engineering involving the deposition of thin organic coatings prepared by plasma enhanced chemical vapour deposition of mixtures of small organic molecules. This approach has been shown highly successful to produce tailored solutions, in the form of pH responsive functional coatings with adjustable surface chemistry and surface charge, to various industrially relevant problems going from absorption of CO2 to controlling the speed of liquid flow in microfluidic devices. The impact of the work described here will be felt on a wider range of applications, going from medical implants, to cell culture material and in the polymer processing industry.*****