DYNAMIC LIGHT-SCATTERING OF IOTA-CARRAGEENAN GELLING SYSTEM

The sol-gel transition of iota carrageenan, a thermoreversible polysac charide gelling system, was investigated using the dynamic light scatt ering technique as a function of concentration and temperature, and th e results were compared with the earlier viscoelastic results on the s ame system. At higher temperatures where the system behaved as a visco us fluid, the field correlation function g((1))(t) is described by a s tretched exponential type of decay in the long time region. As tempera ture decreases, the time profile of g((1))(t) changed, and finally at temperature, T-d, it took the form of a power law type of decay, being a measure of the sol-gel transition point. T-d was observed to be com paratively less than T-c, the temperature at which the power law relax ation was observed in the dynamic viscoelastic (DVE) study. (C) 1998 E lsevier Science B.V. All rights reserved.