title: Self-scrolling ability of differentially acetylated chitosan film.
abstract: Chitosan film cast on a glass slide was exposed to acetic anhydride vapor, resulting in an acetylation gradient in the film, with preferential acetylation of the exposed surface. The difference in degree of acetylation between the two surfaces of the peeled film was confirmed by attenuated total reflection infrared spectroscopy. Upon immersion of the film in water, differential swelling occurred because the more highly acetylated surface absorbed less water, and the resulting bending moment caused self-scrolling with the more highly acetylated surface inside. Simultaneous peeling and scrolling of films with a thickness of micrometer order, using dilute aqueous hydrofluoric acid, afforded tightly rolled chitosan microtubes. This simple self-scrolling mechanism is potentially applicable for micro-scale design with various naturally occurring polymers.
authors.affiliation: Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan. Electronic address: aysaito@mail.ecc.u-tokyo.ac.jp.
authors.forename: Yukie
authors.initials: Y
authors.lastname: Saito
authors.affiliation: Institut de Science des Matériaux de Mulhouse, 15, rue Jean Stacky, Mulhouse 68057, France. Electronic address: valeriy.luchnikov@uha.fr.
authors.forename: Valeriy
authors.initials: V
authors.lastname: Luchnikov
authors.affiliation: Industrial Research Institute of Shizuoka Prefecture, Makigaya, Aoi-ku, Shizuoka 421-1298, Japan. Electronic address: ainaba@iri.pref.shizuoka.jp.
authors.forename: Ayano
authors.initials: A
authors.lastname: Inaba
authors.affiliation: Industrial Research Institute of Shizuoka Prefecture, Makigaya, Aoi-ku, Shizuoka 421-1298, Japan. Electronic address: ktamura@iri.pref.shizuoka.jp.
authors.forename: Katsuhito
authors.initials: K
authors.lastname: Tamura
mesh_terms: D000089:Acetic Anhydrides / Q000737:chemistry; D000107:Acetylation; D048271:Chitosan / Q000031:analogs & derivatives* / Q000138:chemical synthesis*; D046210:Microfluidic Analytical Techniques; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D000089:Acetic Anhydrides; D014867:Water; C031800:acetic anhydride; D048271:Chitosan
keywords: ATR-IR; Acetylation; Chitosan; FT-IR; self-scrolling