Intrinsic viscosity of polyelectrolytes having hydrophobic side‐residues

The intrinsic viscosities [η] of the alternating copolymers from isobutyl vinyl ether and maleic anhydride {p(isoBVE‐co‐MA)}, butyl vinyl ether and maleic anhydride {p(nBVE‐co‐MA)}, ethyl vinyl ether and maleic anhydride {p(EVE‐co‐MA)}, styrene and maleic anhydride {p(St‐co‐MA)}, and indene and maleic anhydride {p(indene‐co‐MA)} were determined and analysed as a function of the molecular weight M and the degree of neutralization β at various NaCl concentrations C s . The following results were obtained: (1) [η] of the polyelectrolytes having hydrophobic side‐residues and divalent‐like carboxyl residues is very small at low charge density β = ≦ 0,2, increasing steeply with ionization until its maximum in the vicinity of β = 0,5. (2) The longrange interaction parameter B e due to the electrostatic repulsive force and the electrostatic part of the expansion factor α (which is defined by the ratio of [η] to its value at infinite ionic strength) exhibits the same behavior as [η] · (3) α can be expressed in terms of ( M / C s ) 1/2 in the same manner as for poly(acrylic acid), being different from the results predicted by many authors. The applicability of Fixman's theory in which B e is a linear function of {article}{empty}{document}1/√ Cₛ{document} was confirmed under consideration of the charge fraction and the bond length.