Thermoreversible gelation and viscoelasticity of κ-carrageenan hydrogels
Date of Issue2016
School of Mechanical and Aerospace Engineering
The gelation behavior of κ-carrageenan in aqueous solution was studied by microdifferential scanning calorimetry and rheology. It was found that the formation and melting of κ-carrageenan hydrogels were thermally reversible and extremely sensitive to κ-carrageenan concentration. In comparison with the crossover of G′ and G″, the extrapolation method based on multiwave oscillation and Winter–Chambon criterion were able to give more accurate critical gel temperature Tc. At the gel point, the critical relaxation exponent n was almost constant whereas the critical gel strength Sg increased with κ-carrageenan concentration. In the stable gel state, the plateau modulus Ge depended on temperature according to a power-law scaling, Ge ∝ ε2.2, where ε is the relative distance (=|T − Tc|/Tc) and independent of κ-carrageenan concentration. The presence of potassium ions shifted the formation and melting temperatures of κ-carrageenan hydrogel to higher temperatures, and the temperatures for gel formation and melting increased with increasing potassium ions' content.
Journal of Rheology
© 2016 AIP Publishing. This paper was published in Journal of Rheology and is made available as an electronic reprint (preprint) with permission of AIP Publishing. The published version is available at: [http://dx.doi.org/10.1122/1.4938525]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.