Critical exponents of thermal phase transitions in κ-carrageenan- water system

Thermal phase transitions of κ-carrageenan in pure water and in KCl solution were studied using photon transmission technique. Photon transmission intensity, I_tr, was monitored against temperature to determine the critical coil-to-helix (T_ch) and helix-to-coil (T_hc) temperatures and exponents, β. T_ch, and T_hc values were found to be higher for the gels containing cations (K⁺) than for those without cations (K⁺). The increase in carrageenan content caused an increase in critical temperatures for the gels prepared in pure water and in KCl solution. Increases in the KCl/carrageenan ratio, raised both T _ch and T_hc values. On the other hand, the critical exponents, β were found to be independent of the system, they are measured by indicating that they fall into the same universality class.