A Videographic Study of Dynamic Phase Separation for Immiscible Solutions under Acoustic Levitation Condition

The transparent aqueous solutions of succinonitrile (SCN) provide an effective model system to simulate the phase separation process of various advanced materials. Here we report a real-time and in-situ study of phase separation dynamics for the SCN-15%H_2O, SCN-48%H_2O and SCN-70%H_2O solutions implemented by high-speed CCD videography together with acoustic levitation technique. It is found that liquid phase separation induces an unsteady state of drop rotation under levitated conditions. The resultant centrifugal force plays the dominant role in the migration of secondary liquid globules. The most desirable homogeneously dispersive structures can only be derived from the earlier stage of phase separation, whereas three kinds of macrosegregation are always the finally stable structure patterns. The migration velocity of minor liquid phase displays the nonlinear feature owing to the variations of globule location and centrifugal force. The surface tensions and volume fractions of immiscible phases also show a conspicuous influence upon the evolution dynamics of separation morphology.