Polyelectrolytes viscometry

Krigbaum, W.R. and Flory, P.J. 1952. Treatment of osmotic pressure data. J. Polym. ScL, 9 503. Kulichke, W. 2004. Viscometry of Polymers and Polyelectrolytes. Springer, New York. 

Polyelectrolyte complexation in aqueous solution between PEI and PMAA has been studied through viscometry, conductometry, potentiometry, and IR spectroscopy [90]. Upon addition of increasing concentrations of PMAA to an aqueous PEI solution, viscosity dropped suddenly around a 1 to 4 ratio of PMAA to PEI because of the complexation and subsequent coiling of the complexed chains. Reduced viscosity then rose past this ratio indicating that the stoichiometry of the complex occurs in a 1 4 (PMAA groups PEI groups) formation. Conductance and titration experiments agreed with this theory. The... 

Water soluble synthetic polyelectrolytes have attracted increasing attention in recent years, mainly because of their wide utility in industrial applications, and also because of their resemblance to biopolymers. PolyCmethacrylic acid), PMA, a wea)c polyelectrolyte, exhibits a mar)ced pH induced conformational transition. A wide variety of techniques have been employed to gain more information on the nature of the conformational transition of PMA, these techniques include viscometry, potential titrimetry,(1-5) Raman spectrometry,(6) calorimetry,(7-9) electrical conductometry,(10) dilatometry,(11) H NMR linewidth,(12) viscoelastic studies,(13) )cinetics of chemical reactions, (14) small-angle neutron scattering,(15) pH jump,(16,17) and fluorescent probing.(18-27)... 

Several methods revealed that PECs between strong polyelectrolytes have a 1 1 end point stoichiometry and also a 1 1 stoichiometry of ionic binding under full release of the low molecular counterions at nonstoichiometric mixing ratios. However, it remains an open question whether the major component in such systems is bound in excess in the PEC structures, giving them a net excess charge. To solve this problem, viscometry, analytical or preparative ultracentrifugation, and fractionation techniques in combination with analyzing methods can be employed. 

However, the application of eqn [1] to the SPEB is less straightforward than anticipated. In principle, the counterion cloud of the polyelectrolyte brushes will be disturbed by the motion of the maaoions leading to electroviscous effects. However, the number of counterions that may leave the brash is small compared to the total number of counterions. When this assumption is valid, this effect can be dismissed and Rh can be determined directly by use of eqn [1]. ° This is also justified when considering Rh which has been determined by dilute solution viscometry. 

MAI Maia, A.M.S., Villetti, M.A., Vidal, R.R.L., Borsali, R., and Balaban, R.C., Solution properties of a hydrophobically associating polyacrylamide and its polyelectrolyte derivatives determined by light scattering, small angle X-ray scattering and viscometry, J. Braz. Chem. Soc., 22, 489, 2011. 

From all these original properties, it follows that to charactraize a polyelectrolyte in aqueous solution for its molar mass and/or dimensions, it is necessary to isolate the chains by screening the long-range electrostatic repulsions. This is achieved in the presence of 0.05 M, or better O.IM, monovalent external salt (NaCl, NaN03, etc.), allowing SEC and viscometry to be used as normally with neutral polymers. 

In a first approach, we have studied the polyelectrolyte properties of a series of Q-P(TDAE)X,. with X = 7, 17, 22, 35 and 48. The conformational and the ionization behaviors of these compounds were investigated by potentiometry, viscometry, laser light scattering and by Optical Rotatory Dispersion (ORD) and Circular Dichroism (CD) for some optically active derivatives.2"4... 

Kul Kulicke, W.M., Clasen, C. Viscometry of Polymers and Polyelectrolytes, Berlin Springer, 2004. 

Polymers 5 and 7 were furthermore studied by viscometry in ultrapure water, in the absence of salt. As an example, values of the reduced viscosity, T[sp/C of 7 are plotted against polymer concentration C. For both polymers, the reduced viscosity increased strongly with decreasing polymer concentrations, exhibiting a pronounced concave-upward relationship (Psp is the specific viscosity) (see Fig. 2). This behavior is typical of polyelectrolytes. ... 

Viscometry is the most widely applied experimental method to determine the conformation of polyelectrolytes. The experiments are easily performed except for the measurements of the shear rate dependence, which is usually neglected (see, however. Sect. 2.3.3 for the importance at low ionic strength conditions). 

The study of the properties of polymers carrying reactive groups, and consequently, of polyelectrolytes, has been undertaken by a wide variety of techniques (potentio-metry, conductimetry, viscometry, light-scattering, NMR, ultrasonic absorption, etc...) which can all be considered as classical in the sense that they can be used in a general manner. 

Takashi Norisuye received his PhD degree in polymer science from Osaka University, Osaka, japan, in 1973. Two years earlier than this, he actually started his tenure work on polymer science as Assistant Professor at the Department of Polymer Science (currently, the Department of Maaomolecular Science), Osaka University. He was promote to associate professor and professor ofthe same department in 1986 and 1996, respectively, and retired in 2007. He is now Emeritus Professor of Osaka Univeisity. Throughout his scientific carrier, he worked on solution properties of macromol niles both theoretically and experimentally with particular interest in excluded-volume effects, helix-coil transition in polypeptides, stiff or rigid chains, polysaccharides, and polyelectrolytes. For those experimental studies, he used sudi t diniques as light and SAlffi, ultracentrifugation, osmometry, polarimetry, NMR, and viscometry. 

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