POLYMER EFFECTS ON THE PHASE-EQUILIBRIUM OF A BALANCED MICROEMULSION - ADSORBING VERSUS NONADSORBING POLYMERS

The phase equilibrium of polymer-microemulsion mixtures has been studi ed. Two polymers with the same cellulose backbone have been examined i n comparison: hydrophobically modified ethyl hydroxyethyl cellulose (H M-EHEC), containing ca. 6.5 hydrophobic ''stickers'' per molecule vers us the unmodified precursor (EHEC). It has been shown that (i) the mod ified polymer is soluble in the bicontinuous microemulsion phase, wher eas the unmodified polymer is not, (ii) HM-EHEC, being dissolved in th e bicontinuous phase increases its ultimate swelling in water and, to a less degree, in oil, and (iii) these effects of HM-EHEC on the phase equilibrium disappear at high polymer concentrations. The influence o f HM-EHEC on the microemulsion phase equilibrium is discussed in terms of the polymer effects on the surfactant monolayer elasticity.