Fluorinated hybrid networks through photopolymerisation processes

Roberta Bongiovanni 1Aldo Priola Giulio Malucelli Marco Sangermano 

1. Politecnico di Torino - Dipartimento di Scienze dei Materiali e Ingegneria Chimica, C.so Duca degli Abruzzi 24, Torino 10129, Italy

Abstract

The use of fluorinated structures in polymeric networks is very attractive due to their outstanding properties, connected to the presence of fluorine, such as chemical and thermal stability, weathering resistance, low surface tension, optical and electrical behaviour. In the last years we have been investigating the homopolymerisation and copolymerisation of fluorinated monomers through the UV curing technique, obtaining interesting materials. A wide range of polymeric networks have been prepared, changing systematically the structures of the monomers and their functionality: it has been showed how not only the fluorine content, but also the structural characteristics of the polymeric matrix and the distribution of the fluorine atoms along the polymeric chains play an important role in the final performances of the materials.

By homopolymerization of fluorinated oligomers, networks exhibiting special morphology and bulk properties have been prepared: in particular when perfluoropolyether structures are present, a biphasic nanostructure is formed.

When the fluorinated products are copolymerised in very low amount (less than 2%w/w) with hydrogenated oligomers by a photoinitiated curing process, a selective migration of the fluorinated monomers to the film surface is observed. Interestingly, the surface composition has been found dependent on the type of the fluorinated chain, its molecular weight, the identity of the end group and the length and the nature of the spacer between the reactive group and the perfluorinated chain. Also the process conditions are relevant to tailor the surfaces of the cured networks.According to the surface enrichment in fluorine, a modification of the surface properties of the UV cured films is achieved while the bulk properties remain unchanged: first the materials become highly hydrophobic and oleophobic, then an improvement of the solvent resistance, antigraffiti properties, lower friction are observed.

 

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Presentation: invited oral at E-MRS Fall Meeting 2005, Symposium E, by Roberta Bongiovanni
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-05-19 14:19
Revised:   2009-06-07 00:44