Impact of Suspended Solids on Coarsening of Ice

Suspended solids, such as silica particles and cellulose fibers, were added to a sucrose aqueous solution, and ice crystals were coarsened at −10 °C. From the radius of the ice crystals, the coarsening rate constant was obtained using the Lifshitz–Wagner equation and the impact of the suspended solid on the coarsening of ice was evaluated. The results showed that the addition of the silica particle suppressed coarsening, but this behavior was not dependent on particle size. It was also shown that cellulose fibers suppressed coarsening more than silica particles. In order to clarify these causes, the present study investigated the correlation between Lw–Lmea and the coarsening rate constants obtained from different suspensions. Lw is the latent heat of fusion (calculated value) corresponding to the water content of the suspension, while Lmea is the latent heat of fusion (measured value) obtained by thermal analysis. A correlation was observed between Lw–Lmea and the logarithm of the coarsening rate constant. Lw–Lmea represents the volume of water that did not form ice crystals on the addition of the suspended solid (volume of unfrozen water at −10 °C), with a larger Lw–Lmea associated with greater inhibition of coarsening. The present findings suggest that suspended solids inhibit coarsening by promoting ice crystal melting.