title: Two-Dimensional Aggregation and Semidilute Ordering in Cellulose Nanocrystals.
abstract: The structural properties and aggregation behavior of carboxymethylated cellulose nanocrystals (CNC-COOH) were analyzed with small angle neutron scattering (SANS), transmission electron microscopy (TEM), atomic force microscopy (AFM), and dynamic light scattering (DLS) and compared to sulfuric acid hydrolyzed cellulose nanocrystals (CNC-SO3H). The CNC-COOH system, prepared from single carboxymethylated cellulose nanofibrils, was shown to laterally aggregate into 2D-stacks that were stable both in bulk solution and when adsorbed to surfaces. CNC-SO3H also showed a 2D aggregate structure with similar cross sectional dimensions (a width to height ratio of 8) as CNC-COOH, but a factor of 2 shorter length. SANS and DLS revealed a reversible ordering of the 2D aggregates under semidilute conditions, and a structure peak was observed for both systems. This indicates an early stage of liquid crystalline arrangement of the crystal aggregates, at concentrations below those assessed using birefringence or polarized optical microscopy.
authors.affiliation: Stranski-Laboratorium, Department of Chemistry, Technische Universität Berlin , Strasse des 17. Juni 124 D-10623 Berlin, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Uhlig
authors.affiliation: Department of Fibre and Polymer Technology, and Wallenberg Wood Science Centre, KTH Royal Institute of Technology, School of Chemical Science and Engineering , Teknikringen 56, 10044 Stockholm, Sweden.
authors.forename: Andreas
authors.initials: A
authors.lastname: Fall
authors.affiliation: Stranski-Laboratorium, Department of Chemistry, Technische Universität Berlin , Strasse des 17. Juni 124 D-10623 Berlin, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Wellert
authors.affiliation: Stranski-Laboratorium, Department of Chemistry, Technische Universität Berlin , Strasse des 17. Juni 124 D-10623 Berlin, Germany.
authors.forename: Maren
authors.initials: M
authors.lastname: Lehmann
authors.affiliation: ESRF - The European Synchrotron , 71, avenue des Martyrs, 38000, Grenoble, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Prévost
authors.affiliation: Department of Fibre and Polymer Technology, and Wallenberg Wood Science Centre, KTH Royal Institute of Technology, School of Chemical Science and Engineering , Teknikringen 56, 10044 Stockholm, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Wågberg
authors.affiliation: Stranski-Laboratorium, Department of Chemistry, Technische Universität Berlin , Strasse des 17. Juni 124 D-10623 Berlin, Germany.
authors.forename: Regine
authors.initials: R
authors.lastname: von Klitzing
authors.affiliation: Department of Fibre and Polymer Technology, and Wallenberg Wood Science Centre, KTH Royal Institute of Technology, School of Chemical Science and Engineering , Teknikringen 56, 10044 Stockholm, Sweden.
authors.forename: Gustav
authors.initials: G
authors.lastname: Nyström
mesh_terms: D001718:Birefringence; D002266:Carboxymethylcellulose Sodium / Q000737:chemistry*; D005427:Flocculation; D006868:Hydrolysis; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D061848:Optical Imaging; D013464:Sulfuric Acids / Q000737:chemistry; D014783:Viscosity
chemical_list: D013464:Sulfuric Acids; D002266:Carboxymethylcellulose Sodium; C033158:sulfuric acid