title: Surface Morphology of Vapor-Deposited Chitosan: Evidence of Solid-State Dewetting during the Formation of Biopolymer Films.
abstract: Chitosan is a useful and versatile biopolymer with several industrial and biological applications. Whereas its physical and physicochemical bulk properties have been explored quite intensively in the past, there is a lack of studies regarding the morphology and growth mechanisms of thin films of this biopolymer. Of particular interest for applications in bionanotechnology are ultrathin films with thicknesses under 500 Å. Here, we present a study of thin chitosan films prepared in a dry process using physical vapor deposition and in situ ellipsometric monitoring. The prepared films were analyzed with atomic force microscopy in order to correlate surface morphology with evaporation parameters. We find that the surface morphology of our final thin films depends on both the optical thickness, i.e., measured with ellipsometry, and the deposition rate. Our work shows that ultrathin biopolymer films can undergo dewetting during film formation, even in the absence of solvents and thermal annealing.
authors.forename: Maria Jose
authors.initials: MJ
authors.lastname: Retamal
authors.affiliation: Instituto de Alta Investigacion, Universidad de Tarapaca , Casilla 7-D, 1000007 Arica, Chile.
authors.forename: Tomas P
authors.initials: TP
authors.lastname: Corrales
authors.forename: Marcelo A
authors.initials: MA
authors.lastname: Cisternas
authors.forename: Nicolas H
authors.initials: NH
authors.lastname: Moraga
authors.forename: Diego I
authors.initials: DI
authors.lastname: Diaz
authors.forename: Rodrigo E
authors.initials: RE
authors.lastname: Catalan
authors.forename: Birger
authors.initials: B
authors.lastname: Seifert
authors.affiliation: Institute of Materials Physics and Technology, Hamburg University of Technology (TUHH) , D-21073 Hamburg-Harburg, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Huber
authors.forename: Ulrich G
authors.initials: UG
authors.lastname: Volkmann
mesh_terms: D048271:Chitosan / Q000031:analogs & derivatives*; D049329:Nanostructures / Q000737:chemistry*; D058105:Polymerization; D014835:Volatilization; D017155:Wettability
chemical_list: D048271:Chitosan