Influence of various apolar groups in polycationic polyorganosiloxanes upon polyion complexation with poly(methacrylic acid)

Polyion complexes are formed from poly(methacrylic acid) and polycationic polyorganosiloxanes modified with various apolar groups in the main chain or in the side chains. Potentiometric titration measurements with solutions of the complexes indicate that the chemical structure of the composed polycation influences complexation in aqueous solution. From a binding study with methyl orange, it is seen that the electrostatic interaction of the polyion complexes is enhanced by an increase of the hydrophobicity in the composed polycations. In water/ethanol solutions, however, such a tendency is not observed.