Dual polyelectrolyte-ionomer behavior of poly(acrylic acid) in methanol: 2. Salt solutions

The influence of tetramethylammonium chloride on a polyelectrolyte-ionomer behavior of poly(acrylic acid) (PAA) partly neutralized with tetramethylammonium hydroxide in methanol was studied by the viscometry and conductivity methods. It was shown that the addition of a small amount of this low-molecular-weight salt decreases the size of macromolecules in the polyelectrolyte state. When the salt concentration rises, the tendency toward formation of ion pairs is enhanced and the ionomer state becomes thermodynamically more advantageous than the polyelectrolyte state. As a result, macromolecules are transformed into the ionomer state at degrees of polymer neutralization corresponding to the polyelectrolyte behavior of salt-free solutions.