title: Water-induced local ordering of chitosan polymer chains in thin layer films.
abstract: Carbon-13 NMR (CP-MAS and FSLG (1)H-(13)C HETCOR) have been applied to chitosan salt films synthesized in acetic acid and exposed to different relative humidity environments (32% or 75%) at 20°C for 1 month. It gives insight in the relationship between structure and functional properties according to the hydration level of this biomaterial as a film. The acetate ions trapped in the chitosan act as structuring agents between chitosan chains for the low hydration state. But, increasing the moisture content induces spontaneous removal of acetic acid and a subsequent modification in the film structure, with an increase in local ordering. HETCOR experiments also showed a multiplicity of signals for most of the observed carbon atoms and in particular those implied in the glycosidic linkage, which reveals different water-induced conformational states. Changing the water content allows to modify the polymer structure and therefore to modulate the properties such as controlled release of active compounds trapped in chitosan-based coatings, e.g., for medicated dressing or active packaging.
authors.affiliation: UMR A 02.102 PAM, Université de Bourgogne/AgroSup Dijon, Equipe PAPC, 1 esplanade Erasme, F-21078 Dijon, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Madeleine-Perdrillat
authors.affiliation: UMR A 02.102 PAM, Université de Bourgogne/AgroSup Dijon, Equipe PAPC, 1 esplanade Erasme, F-21078 Dijon, France. Electronic address: thomas.karbowiak@u-bourgogne.fr.
authors.forename: Thomas
authors.initials: T
authors.lastname: Karbowiak
authors.affiliation: Univ Strasbourg, Inst Chim, UMR CNRS 7177, BP 296, F-67008 Strasbourg, France.
authors.forename: Jesus
authors.initials: J
authors.lastname: Raya
authors.affiliation: UMR A 02.102 PAM, Université de Bourgogne/AgroSup Dijon, Equipe PAPC, 1 esplanade Erasme, F-21078 Dijon, France.
authors.forename: Régis
authors.initials: R
authors.lastname: Gougeon
authors.affiliation: IUT A - Université des sciences et technologies de Lille, F-59653 Villeneuve d'Ascq, France.
authors.forename: Philippe R
authors.initials: PR
authors.lastname: Bodart
authors.affiliation: UMR A 02.102 PAM, Université de Bourgogne/AgroSup Dijon, Equipe PAPC, 1 esplanade Erasme, F-21078 Dijon, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Debeaufort
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011108:Polymers / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D011108:Polymers; D014867:Water; D048271:Chitosan
keywords: Chitosan; NMR; Polymer; Structure; Water