Swelling of iota-carrageenan gels prepared with various CaCl2 content: A fluorescence study

Abstract

AbstractIota carrageenan gels prepared with various CaCl2 content were completely dried and then swelled in water vapor. Steady-state fluorescence (SSF) technique was used to monitor the swelling process of each iota carrageenan gels at various temperatures. Pyranine was used as a fluorescence probe. Apparent fluorescence intensity, I increased as swelling time increased for all gel samples. The increase in I was modelled using Li-Tanaka equation from which the swelling time constants, τ1 and cooperative diffusion coefficients, Dc were determined. It was observed that Dc increased as the swelling temperature was increased. On the other hand at each temperature, it was seen that Dc decreased as CaCl2 content was increased. Activation energies for swelling were obtained and found to be 60.5, 61.0, 61.5 and 62.8 kJmol-1 for the gels prepared with increasing amount of CaCl2 content.