Article,

Comparative studies on molecular chain parameters of chitosans and poly(diallyldimethylammonium chloride): the stiffness B-parameter and the temperature coefficient of intrinsic viscosity

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Carbohydr. Polym., 48 (2): 171 -- 178 (May 2002)

Abstract

The empirical coefficient B, a measure of polyelectrolyte chain stiffness was estimated for two types of polycations: chitosans with FA (mote fraction of N-acetyl-D-glucosamine units) ranging from 0.09 to 0.21 (determined by H-1 NMR method) and poly(diallyldimethylammonium. chloride) (PDADMAC), in the presence of different counterions (Cl-, Br-, NO3-, ClO4-). The method relies on the measurements of the intrinsic viscosity, eta, of polyelectrolyte chains at different solution ionic strength (1). Thus, the B-parameter shows the response of the hydrodynamic volume of polyelectrolyte molecules to the salt concentration in solution (the so-called salt tolerance) referred to the eta at I = 0.1 M. The temperature coefficient of intrinsic viscosity of PDADMAC and chitosan was also determined. The comparison of the B-parameters indicates lower flexibility of chitosan than PDADMAC. The reasons for this difference are discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.

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