Celine Croutxe Barghorn

Celine Croutxe Barghorn

Laboratory of Photochemistry and Macromolecular Engineering, France



Biography

Celine Croutxe - Barghorn graduated in chemistry at the University of Bordeaux (France) and the Technische Hochschule of Darmstadt (Germany). She attained her PhD in physical chemistry in 1996 at the University of Haute Alsace (France). Her work focused on the use of photopolymers for the generation of optical elements. She is currently Professor at University of Haute Alsace and head of the research group “Photochemistry in Organic and Hybrid Materials” (POHM) in the Department of Photochemistry. Her present research interest is the study of the photopolymerization processes in hybrid sol-gel glasses, nanocomposites and all organic resins and their characterization for specific applications (coatings or bulk materials). 

Abstract

Photochemical   generation   of   free   radicals   and   acids   is   a widely   used   process   in photopolymerization reactions. Recently, photobase generators (PBG) systems have emerged as new source of initiating species allowing the catalysis of different reactions (thiol-Michael, thiol-isocyanate, thiol-epoxy…). The versatility of PBGs will be highlighted through different examples. The process of light-triggered polymerization of dopamine will be first described. Irradiation   of   quaternary   ammonium   salts   of   phenylglyoxylic   acid   used   as   photobase generators activates the release of a strong base in water followed by an important pH jump. This initiates the polymerization of dopamine, leading to an on-demand formation of highly adhesive coating on steel.  Then,  photopolymerization  of  a  thiol/epoxy/isocyanate  ternary network  was  thoroughly  investigated.  Polymerization kinetics  demonstrated  that  the  thiol- isocyanate reaction is completed in a matter of seconds while the thiol-epoxy reaction exhibits a catalytic character over a few days leading to a post-consolidation of the coating. Moreover, the  presence  of  the  thiourethane  network  enhances  the  thiol-epoxy properties  by increasing the   physical   cross-linking  due   to   higher   content   of   hydrogen   bonding.   Compositional variations between thiol/epoxy and thiol/ isocyanate and the resulting final thermomechanical properties and hardness offer many advantages in the development of materials with tunable properties.