Gelatin coacervation systems were examined in the mixing concentration range of 0.2 to 1.3% gelatin at 40 and 30°. The weight-average molecular weights of the gelatins were 3.3 × 105 in 2.0 M KCNS. The equilibrium liquids contained aggregates (salt free) with molecular weights on the order of 1-2 × 106. In contrast, the equilibrium liquids diluted in 2.0 M KCNS were shown to have molecular weights on the order of 1-2 × 105 and the gelatin in the coacervate phases had molecular weights correspondingly higher than the original average gelatin molecular weight. The fractionation had a more pronounced effect on the phase equilibrium than predicted previously. The other features of the basic model of the coacervation process have been confirmed. In particular, the presence of dense aggregates in the dilute phase shows that entropy factors provide the driving force for the phase separation.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry