The reaction between poly(1-vinylimidazole) and poly(acrylic acid) with var
ious extents of neutralization was studied by potentiometric titration and
IR spectroscopy. It was shown that an interpolymer complex stabilized by hy
drogen bonds is formed at the extent of polyacid neutralization varying in
the range from 0 to 0.9. When the extent of polyacid neutralization is abov
e 0.9, the interpolymer complex is formed through a donor-acceptor interact
ion between the imidazole units and the carboxylate anions. It is demonstra
ted that the chemical nature and the concentration of the alkali-metal ion
affect the extent and the character of interpolymer interactions.