The literature values of the intrinsic viscosity-molecular weight dependence of some polyelectrolytes have been analyzed on the basis of Yamakawa's theory in order to derive the persistence length q with a computer fitting procedure. Sodium polyacrylate, poly(styrenesulfonate), poly[((acrylamido)methyl)propanesulfonate], (carboxymethyl)cellulose, and the sodium salt of an isobutyl vinyl ether-maleic anhydride copolymer have been investigated in the 1.0-0.005 M ionic strength range. The persistence lengths ip, determined by extrapolation to infinite ionic strength with a linear q vs. 7"1/2 plot, agreed with those of the corresponding uncharged polymers. In addition, the q values of the vinylic polyelectrolytes appeared to extrapolate toward a similar value, about 500 Á, at infinite dilution, indicating a high degree of rigidity. The observed 7~^2 dependence of the electrostatic contribution to the persistence length le differed from the 7'1 dependence predicted in the Odijk-Skolnick-Fixman theory and agreed, at least semiquantitatively, with that calculated from the recent treatments of Le Bret and Fixman. The influence of the ionization degree on the persistence length of sodium polyacrylate was also studied.
Electric birefringence observations on sodium poly(styrenesulfonate) samples of narrow molecular weight distribution have been used to investigate the influence of concentration and molecular weight on their polyelectrolyte properties. The shape of the orientation function was found to approach that of an induced dipole mechanism at low molecular weight but tended toward that of a permanent dipole mechanism at high molecular weight. Although we found that the orientation function of Kikuchi and Yoshioka for a saturating induced dipole could account for this behavior, we showed that the residual polydispersity of the samples was sufficient to justify the fitting of the birefringence curves with the orientation function for a pure induced dipole using two or three polarizability terms. This analysis reinforced our opinion that the shape of the orientation function is not an adequate criterion to distinguish between various orientation mechanisms. The electric polarizability determined either from the Kerr constant or from the fittings of the whole birefringence curves was found to increase with the 2.6 power of the molecular weight M for M smaller than 200 000. This is in fairly good agreement with the predictions of the Manning and Fixman theories. The calculated polarizability values were, however, 1.5-2 times smaller than the experimental values. Possible origins for this discrepancy are discussed.
S U M M A R Y :The solution properties of poly(5-p-menthyl methacrylate) and poly(2-tert-butylphenyl methacrylate) are determined by several methods in good and ideal solvents. The flexibilities 0 calculated on the basis of the unperturbed dimensions are 3,l and 2,6, resp. These values are compared with those found for other polymethacrylates with bulky substituents. The influence of a large group in ortho position at the cyclohexyl and the phenyl rings is discussed in terms of steric hindrance and specific interactions.
Z U S A M M E N F A S S U N G :Die Losungseigenschaften von Poly(5-p-menthylmethacrylat) und Poly(2-tert-butylphenylmethacrylat) werden nach verschiedenen Methoden in guten und idealen Losungsmitteln bestimmt. Die Kettenbeweglichkeit wird mit Hilfe der umgestorten Dimension berechnet; 0 ist 3,l fur das Poly(5-p-menthylmethacry1at) und 2,6 fur das Poly(2-tert-butylphenylmethacrylat). Diese Werte werden mit denen einiger anderer Polymethacrylate verglichen, die voluminose Substituenten in der Kette besitzen. Der EinfluCi einer groRen Gruppe in der ortho-Stellung von Cyclohexyl-und Phenylringen wird auf Grund der sterischen Behinderung und der spezifischen Wechselwirkungen diskutiert.
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