USE OF ISOTHERMAL TITRATION MICROCALORIMETRY TO MONITOR THE ADSORPTION DESORPTION PROCESSES OF SODIUM DODECYL-SULFATE WITH NEUTRAL POLYMERS/

The optimization of neutral polymer/anionic surfactant mixtures is a c ritical process in the development of such systems for many various ap plications. In this report, we describe how systematic isothermal titr ation microcalorimetry experiments may be designed in such a way that both the adsorption and desorption processes of sodium dodecyl sulfate with two neutral polymers, PAPR (a copolymer of N-(vinylacryloyl)pyr rolidine containing a covalently bonded 4-vinylpyridine dicyanomethyli de chromophore) and PVP (poly(N-vinylpyrrolidone)), can be directly mo nitored. The desorption of bound SDS from the polymers is achieved usi ng the nonionic surfactant hexaethylene glycol mono-n-dodecyl ether an d the possible mechanism via which this process takes place is qualita tively discussed. Finally, one of the beneficial outcomes stemming fro m this work is that different stable combinations of polymer or polyme r/surfactant complex with mixed micelles and monomer surfactant can be formulated.