Measuring microrheological properties of porous biopolymers in liquid

With growing interests in utilizing soft biological materials for soil improvement, it is crucial to understand the mechanical characteristics biopolymers to predict the behavior of the biopolymer-treated soils. This study presents rheological parameters of insoluble and porous polysaccharidic biopolymer, which has a potential to be used for soil enrichment. Due to the internal porosity and high heterogeneity of dextran, the traditional rheometer would be inadequate to measure representative properties. Instead, particle-tracking microrheology technique was employed to obtain reliable rheological properties of dextran in liquid where Brownian motions of small fluorescent beads trapped in porous dextran structure were recorded at 100 Hz. The frequencydependent complex shear moduli were found; the storage modulus ranged ~0.01–0.1 Pa and the loss modulus was in the range of ~0.001–0.1 Pa in the frequency of ~1–100 Hz.