A Percolation Approach for Investigating the Sol-Gel Phase Transition of κ-Carrageenan: A Steady-State Fluorescence Study

Abstract

A steady-state fluorescence technique was employed to study sol-gel transitions in K-carrageenan systems at various carrageenan concentrations. Scattered light, Isc, and fluorescence intensity, I, were monitored against temperature to determine critical phase transition temperatures and exponents. Pyranine was used as a fluorescence probe to monitor these phase transitions. It was observed that coil-to-helix (sol-gel) transition temperatures, Tch, strongly correlated with carrageenan concentration. The weight average degree of polymerization, DPw and gel fraction G, exponents (γ and β) were measured and found to be in accord with the classical Flory-Stockmayer model.