(92h) Microrheology and Structural Reconfiguration of Artificial Biofluids Composed of Xanthan Gum in Salt Solutions
AIChE Annual Meeting
Monday, October 30, 2017 - 10:00am to 10:15am
Solutions of various concentrations of xanthan gum and salt are investigated. At high concentrations of xanthan gum, we observe that the particles are inhibited from free diffusion, indicative of a purely elastic response from the material, which is consistent with the bulk rheology. However, for lower concentrations, we observed that the particles showed a super-diffusive behavior on the order of hours to days. We hypothesize that this behavior is a result of the rearrangement of the structures of the solutions over this timescale, and we use the transient changes in the MSD to provide structural information of this reconfiguration process. After equilibrium is reached, consistent short-time sub-diffusive behavior and long-time diffusive behavior is observed. These results indicate that the particles are able to eventually escape the cages of xanthan gum, and the intersection of the two regions can be used to estimate the cage size and the relaxation time of the solutions.