POLYMER-INDUCED PHASE-SEPARATION IN LYOTROPIC SMECTICS

Large water soluble macromolecules can be confined in all proportions into an electrostatically stabilized surfactant lamellar phase without change of the bilayer thickness. Upon progressive addition of salt, t he sample phase separates into a polymer-rich and a surfactant-rich la mellar phase. Indeed, at some particular salt concentration, the inter membrane repulsive interaction is no longer sufficient to maintain the polymer coils squeezed into the lamellar structure. The phase separat ion is generally first order. But we could find a situation where it b ecomes second order.