Intermolecular interactions of polymethacrylic acid with N-alkyl-1,3-propanediamine

The relation between Coulomb and hydrophobic interactions in the development of associative processes is established on the basis of the concentration dependences of pH for binary solutions of anionic polyelectrolyte-polymethacrylic acid and cationic surfactant-N-alkyl-1,3-propanediamine. It is demonstrated that the criterion for determining the predominant contribution from either Coulomb or hydrophobic interactions is the maximum for the dependence of the pH difference between individual solutions of N-alkyl-1,3-propanediamine and binary solutions of polymethacrylic acid and N-alkyl-1,3-propanediamine on the logarithm of the product of their concentrations.