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A dynamic laser light‐scattering study of chitosan in aqueous solution
Author(s) -
Wu Chi,
Zhou Shuiqin,
Wang Wei
Publication year - 1995
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360350406
Subject(s) - chemistry , aqueous solution , chitosan , analytical chemistry (journal) , dynamic light scattering , molar mass distribution , polyelectrolyte , calibration curve , diffusion , chromatography , polymer , thermodynamics , chemical engineering , organic chemistry , physics , detection limit , nanoparticle , engineering
The solution behavior of four chitosans (91% deacetylated chitin) with different molecular weights in 0.2 M CH 3 COOH/0.1 M CH 3 COONa aqueous solution was investigated at 25°C by dynamic laser light scattering (LLS). The Laplace inversion of the precisely measured intensity‐intensity lime correlation function leads us to an estimate of the line‐width distribution G (Γ), which could be further reduced too translational diffusion coefficient distributions G ( D ). By using a combination of static and dynamic LLS results, i.e., M w and G ( D ), we were able to establish a calibration of D = k D M −α Dwith k D = (3.14 ± 0.20) × 10 −4 and α D = 0.655 ± 0.015. By using this calibration, we successfully converted G ( D ) into a molecular weight distribution f w ( M ). The larger α D value confirms that the chitosan chain is slightly extended in aqueous solution even in the presence of salts. This is mainly due to its backbone and polyelectrolytes nature. As a very sensitive technique, our dynamic LLS results also revealed that even in dilute solution chitosan still forms a small amount of larger sized aggregates that have been overlooked in previous studies. The calibration obtained in this study will provide another way to characterize the molecular weight distribution of chitosan in aqueous solution at room temperature. © 1995 John Wiley & Sons, Inc.