Viscoelastic Properties of Iota-Kappa-Carrageenan Gels through Single-Particle Tracking Microrheology

Abstract

The gelation of the mixtures of iota-carrageenan (iC) and kappa-carrageenan (kC) is widely studied using different methods such as rheological experiments to understand the properties of the mixed carrageenan gels. This paper investigates the viscoelastic properties of mixed iC/kC gels at a ratio of 1:3 (25iC/75kC) in the presence of 30mM KCl at 21°C using Single-Particle Tracking Microrheology (SPTM) with video microscopy. Specifically, the MSD, and the viscous and elastic moduli of the iC/kC gel were measured and analyzed. The results were compared to the findings of related studies on bulk rheological data. The results show that the diffusion of the beads in the gel mixture is anomalous and is strongly sub-diffusive. The gel’s elastic modulus is higher than its viscous modulus. This result is consistent with the findings of bulk rheological studies which mixed iC/kC gel properties in relative proportion to the component concentrations, this ratio are stiffer gels. The 25IC/75KC gel shows a solid-like gel behavior.