title: Pore size determination of TEMPO-oxidized cellulose nanofibril films by positron annihilation lifetime spectroscopy.
abstract: Wood cellulose nanofibril films with sodium carboxylate groups prepared from a 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized pulp exhibited an extremely low oxygen permeability of 0.0008 mL μm m(-2) day(-1) kPa(-1) at 0% relative humidity (RH). Positron annihilation lifetime spectroscopy (PALS) was used to determine the pore sizes in wood and tunicate TEMPO-oxidized cellulose nanofibril (TOCN-COONa) films in a vacuum (i.e., at 0% RH). PALS analysis revealed that the pore size of the wood TOCN-COONa films remained nearly at 0.47 nm from the film surface to the interior of the film. This is probably the cause of this high oxygen-barrier properties at 0% RH. The crystalline structure of TOCN-COONa also contributes to the high oxygen-barrier properties of the wood TOCN-COONa films. However, the oxygen permeability of the wood TOCN-COONa films increased to 0.17 mL μm m(-2) day(-1) kPa(-1) at 50% RH, which is one of the shortcomings of hydrophilic TOCN-COONa films.
authors: Department of Biomaterials Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan.
authors: Hayaka
authors: H
authors: Fukuzumi
authors: Tsuguyuki
authors: T
authors: Saito
authors: Shinichiro
authors: S
authors: Iwamoto
authors: Yoshiaki
authors: Y
authors: Kumamoto
authors: Toshiyuki
authors: T
authors: Ohdaira
authors: Ryoichi
authors: R
authors: Suzuki
authors: Akira
authors: A
authors: Isogai
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D003497:Cyclic N-Oxides / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D057139:Nanofibers / Q000737:chemistry*; D016877:Oxidants / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D010539:Permeability; D016062:Porosity; D013057:Spectrum Analysis; D013499:Surface Properties
chemical_list: D003497:Cyclic N-Oxides; D016877:Oxidants; D002482:Cellulose; D010100:Oxygen; C003959:TEMPO