Excluded‐volume effects on the chain dimensions and transport coefficients of sodium poly(styrene sulfonate) in aqueous sodium chloride

Abstract

Fifteen samples of sodium poly(styrene sulfonate) with weight-average molecular weights of 3 ϫ 10 4 to 8 ϫ 10 5 have been studied by static and dynamic light scattering and viscometry in 0.05 and 0.5 M aqueous NaCl at 25°C. The measured radii of gyration, translational diffusion coefficients, and intrinsic viscosities at the lower salt concentration exhibit molecular weight dependencies stronger than those predictable for uncharged flexible chains in the good solvent limit. These data and those at the higher NaCl concentration are analyzed, along with previous intrinsic viscosity data covering a broad molecular weight range, in the framework of the quasi-two-parameter (QTP) theory with the wormlike chain as the model. It is shown that the relevant theories for the expansion factors in the QTP scheme combined with these theories for the unperturbed wormlike chain are capable of describing the experimental data with a degree of accuracy similar to that known for nonionic flexible polymers.

Chain Stiffness and Excluded-Volume Effects in Polyelectrolyte Solutions: Characterization of Sodium Poly(2-acrylamido-2-methylpropanesulfonate) in Aqueous Sodium Chloride

“…The q values for Na PAMPS in Table II are comparable to those reported previously 8,11 for Na PSS in aqueous NaCl with the corresponding salt concentrations (1.5 nm at C s ¼ 0:5 M and 2.7 nm at C s ¼ 0:05 M, both from []), indicating that the two polyelectrolytes have similar stiffness in the aqueous salts. On the other hand, the B values for Na PAMPS are considerably larger than those for Na PSS (1.6 nm at C s ¼ 0:5 M and 4.0 nm at C s ¼ 0:05 M).…”

“…The (total) persistence lengths of 1:5 (AE 0:1) nm at the higher C s and 3.0 nm at the lower C s are comparable to those for Na PSS 8,11 in the corresponding solvents, indicating that the two polyelectrolytes have similar chain stiffness. The electrostatic contributions to q may also be similar, but discussions on q el are deferred to the forthcoming paper, in which both q el and the electrostatic excluded-volume strength for Na PAMPS in aqueous NaCl will be examined as functions of ionic strength.…”

“…[5][6][7][8] The major problem in the estimation of q el is that excluded-volume and stiffness effects can hardly be separated for those polymers without resort to a relevant excluded-volume theory. In previous studies, [5][6][7][8][9][10][11] we utilized the quasi-two-parameter (QTP) theory (the Yamakawa-Stockmayer-Shimada theory) [12][13][14] for the wormlike chain 15 or, more generally, the helical wormlike chain 14 to estimate these effects in aqueous NaCl solutions of sodium hyaluronate and sodium poly(styrenesulfonate) (Na PSS).…”

“…[5][6][7][8] The major problem in the estimation of q el is that excluded-volume and stiffness effects can hardly be separated for those polymers without resort to a relevant excluded-volume theory. In previous studies, [5][6][7][8][9][10][11] we utilized the quasi-two-parameter (QTP) theory (the Yamakawa-Stockmayer-Shimada theory) [12][13][14] for the wormlike chain 15 or, more generally, the helical wormlike chain 14 to estimate these effects in aqueous NaCl solutions of sodium hyaluronate and sodium poly(styrenesulfonate) (Na PSS). Except for some details, the QTP scheme satisfactorily explained the molecular weight dependence of intrinsic viscosity [] and mean-square radius of gyration hS 2 i for the two polyelectrolytes at fixed salt concentrations C s higher than 10 À2 M. On the other hand, the available polyelectrolyte theories [1][2][3][4]16 failed to describe the C s dependence of the estimated q el and excluded-volume strength, though the degree of disagreement appeared to depend on the intrinsic chain stiffness.…”

Chain dimension of polyampholytes in solution and immobilized brush states

“…The value of k¢ H for typical flexible polymers in a good solvent was reported over a range from 4 to 6. 38 The value of k¢ H calculated from the literature data 39 Figure 3 shows the C s dependence of k¢ H for free PMAPS (J) and PMPC (&) in aqueous NaCl solutions at 25 1C, together with that of free poly(styrene sulfonate sodium salt) (NaPSS; M w ¼2.56Â10 5 g mol À1 ) 41 (D) and poly(2-acrylamido-2-methylpropanesulfonate sodium salt) (NaPAMPS; M w ¼2.76Â10 5 g mol À1 ) 42,43 (B) with the same molecular weight. The values of k¢ H for PMAPS and PMPC in aqueous NaCl solutions were revealed to be 1.5-8, which may be regarded as a y-state and a good solvent state, indicating the reduction in intramolecular and intermolecular interaction between polymer chains with increasing C s .…”