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Characterization of Clusters and Unimers in Associating Solutions of Chitosan by Dynamic and Static Light Scattering
Author(s) -
Skorik Yury A.,
Petrova Valentina A.,
Okatova Olga V.,
Strelina Irina A.,
Gasilova Ekaterina R.
Publication year - 2016
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201600146
Subject(s) - chemistry , macromolecule , dynamic light scattering , viscometer , static light scattering , solvent , light scattering , salt (chemistry) , polymer chemistry , colloid , cluster (spacecraft) , analytical chemistry (journal) , scattering , chemical engineering , chromatography , organic chemistry , viscosity , nanoparticle , thermodynamics , biochemistry , physics , optics , engineering , computer science , programming language
Association of two chitosans of different degrees of acetylation (DA) is studied in dilute water/acid/salt solutions by combined analysis of static and dynamic light scattering. The influence of sodium salt anions Cl − and CH 3 COO − on conformation of macromolecules and properties of clusters was studied. At DA = 15 mol%, the macromolecules exist either in rigid‐rod ( R g / R h = 2.7) or in coil ( R g / R h = 1.8) conformations in the solvents containing NaCl and CH 3 COONa, respectively. Chitosans with higher DA = 28% dissolved in the solvent containing CH 3 COONa are in the collapsed state ( R g / R h < 0.8), predicted by Dobrynin (Macromolecules, 2004). The clusters are of spherical form (0.8 < R g / R h < 1.2). CH 3 COONa promotes higher fractal dimensionality of clusters (2.2–2.4) than NaCl (1.9). Higher critical aggregation concentration is observed in NaCl. The other hydrodynamic methods (capillary viscometry, velocity sedimentation, and Tsvetkov diffusometry) do not detect the clusters, probably, because of their disruption during flow.