Effects of alcohols and temperature on association, micellar parameters, and energetics of mixture of cetylpyridinium bromide and polyvinyl alcohol

Abstract

The mixture of polymer and surfactant is extensively employed in numerous daily used products such as detergents, perfumes, cleaning agents, foodstuffs, oil recovery procedures, paints, as well as pharmaceutical formulations. Interaction of cetylpyridinium bromide (CPB) with polyvinyl alcohol (PVA) has been investigated in water and aqueous solution of different alcohols using the conductivity technique. The type and strength of interaction between CPB and PVA during assembly process have been assessed from different micellar parameters i.e., critical micelle concentration (CMC), extent of counterion dissociation (α), Gibbs free energy (ΔGm0), enthalpy (ΔHm0), entropy (ΔSm0) of micellization etc. The CMC and α were determined from the specific conductivity vs [CPB] plots. The micellization of CPB was attained to be augmented in occurrence of PVA. The CMC values of CPB + PVA system were experienced to be increased through the elongation of chain length of carbon as well as increase of concentration of certain alcohol. The sharp increase of CMC values was also observed with the increase of temperature in a certain alcoholic medium. The values of degree of dissociation were undergone to be augmented by the increase of concentration of certain alcohol as well as the elongation of carbon chain length. The negative free energy of micellization (-ΔGm0) values reveal that the CPB + PVA system undergoes aggregation spontaneously and spontaneity of micellization experienced a reduction with the elongation of carbon chain length. Values of enthalpy (ΔHm0) of micellization were negative i.e., aggregation of CPB + PVA system is an exothermic phenomenon. The ΔHmoandΔSmo values disclose that the main interaction forces between CPB and PVA are electrostatic, hydrophobic, and ion–dipole interactions. The stability of the micelle formed was assessed from enthalpy-entropy compensation parameters.