ELECTROSTATIC CONTRIBUTION TO THE INTERACTION OF ALPHA,BETA-POLY(N-HYDROXYETHYL)-DL-ASPARTAMIDE WITH SODIUM DODECYL-SULFATE MICELLES

The enthalpic effect due to the interaction between alpha, beta poly(N -hydroxyethyl)-DL-aspartamide (PHEA) and sodium dodecylsulfate (SDS) i n, aqueous solutions as a function of the surfactant concentration was measured by the calorimetric technique at various NaCl concentrations . A marked influence of the added electrolyte on the PHEA-SDS interact ion was observed. An analysis of the experimental enthalpies allows to estimate the electrostatic and the hydrophobic contributions to the e nthalpy of interaction between PHEA and SDS micelles. The results were rationalized in terms of effects due to the screening of the charges residing on PHEA and SDS micelles.