Critical Exponents of Thermal Phase Transitions of kappa-Carrageenan in Various Salt Solutions

Abstract

The steady state fluorescence (SSF) technique was employed to study the phase transitions Of kappa-carrageenan in NaCl and KCl solutions. Pyranine was used as a fluorescence probe for monitoring these transitions. Scattered light I(sc) and fluorescence intensity 1 was monitored against temperature to determine transition temperatures and exponents. It was observed that transition temperatures are strongly correlated with the NaCl and KCl contents. The weight-average degree of polymerization DP(w) and gel fraction G exponents (gamma and beta) were measured and found to be in accord with the classical Flory-Stockmayer model.