Anomalous ice nucleation behavior in aqueous polyvinyl alcohol solutions

The effect of polymers on the ice nucleation temperature (Tf) was studied in a W/O emulsion using ∼5 μm diameter droplets by differential scanning calorimetry (DSC). Four types of polymers were used. Among them, only polyvinyl alcohol (PVA) showed the additional effect of increasing the Tf of the aqueous solutions. This increase was logarithmic with the concentration of PVA and the difference in molecular weight did not have any significant effect on Tf for the same weight concentration. It was shown that the number of the structural unit (CH2CHOH) was the key parameter for the increasing degree of Tf.