Time-resolved dynamic light scattering study on gelation and gel-melting processes of gelatin gels

The gelation and gel-melting processes have been investigated by time-resolved dynamic light scattering for gelatin aqueous solutions (1) during both cooling and heating processes with a fixed rate (0.10 degreesC/min) and (2) after quenching from 50 to 10 degreesC. In both cases, the gelation threshold was clearly observed as (i) appearance of strong fluctuations in scattered intensity, (ii) a power-law behavior in the time-intensity correlation function (ICF), and (iii) deviation of the initial amplitude of ICF. The physical implication of these phenomena is discussed.