EFFECT OF DEVALENT SALTS ON THE BINARY LIQUID-LIQUID PHASE SEPARATION OF C_8-LECITHIN MICELLAR SOLUTIONS
两价盐对C_8－卵磷脂微团溶液液－液相分离的影响

This paper presents the coexistance curves of binary liquid-liquid phase separation in aqueous micellar solutions of C8-lecithin,as a function of the concentration of divalent salts (CaI2, CaBr2, CaCl2, MgBr2, MgCl2),measured with laser light scattering tecnique. Dif fering from monovalent salts, the divalent cations are dominative in influencing the critical temperature (Tc) for the phase separation of the micellar solutions. Ca2+ increases Tc as the ionic strength is increased. Mg2+,however,first increases and then lowers Tc as the ionic strength is increased. The identity of the added ahions has a comparatively minor effect on Tc.Iodides are more effective in changing To than bromides, while chlorides are the least.A Gibbs free energy model is ed to analyze the dependence of Tc on salt identity and concentration for the micellar solutions. The deduced semi-empirical formula with this model for both divalent and monovalent salts agrees Well with our experimental findings.