The behavior of poly(acrylic acid) (PAA) partly neutralized with tetramethylammonium hydroxide in methanol was studied by the viscometry, 1 H NMR spectroscopy, light scattering, and conductivity methods. It was shown that, when the degree of PAA neutralization increases from 0.1 to 0.2, a transition from a polyelectrolyte to ionomer state occurs. This transition is caused by the formation of ion pairs due to the binding of counterions with the charged groups of the polymer chain and is accompanied by a macromolecule collapse. Collapsed macromolecules aggregate. At degrees of neutralization above 0.4, the restored polyelectrolyte state is accompanied by polymer swelling. The data obtained are qualitatively explained.

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.

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