Aging dynamics in gelatin gel microstructure

Gelatin is a biological polymer that forms thermoreversible gels. Even after formation, the structure of the gel is not static and continues to evolve and change because of the instability of the low energy interactions that connect the gel network. Rheological and dynamic light scattering (DLS) measurements were used to observe the development and evolution of the gel network structure during gelation. Rheological measurements were used to monitor the rate of increase in the number and strength of elastically effective chains as the network forms. Two power law scaling regions were observed; one where the aggregation process dominates and a second, where the rearrangement process dominates. DLS suggested that there were three evolving levels of structure in the gel network: small clusters, large groups of clusters and very large assemblies. For small clusters, the correlation length decreased as the concentration increased. For the large groups, increasing the setting temperature increased the maximum correlation length. Scattered intensity data suggested that large groups lose their integrity as the gel network rearranges. (C) 2003 Elsevier Science Ltd. All rights reserved.