6533b7dafe1ef96bd126e017

RESEARCH PRODUCT

Experimental studies of the rheological behavior of a demixing biopolymeric sol

subject

description

Experimental data are presented concerning a large transient viscosity surge occurring in the course of spinodal demixing of agarose aqueous solutions. The study includes the effects of water perturbation by minor proportions of compatible cosolutes. Three observations are noteworthy. One concerns an upward or downward shift of the spinodal temperature, caused by cosolutes, which agrees with their expected modulation of solvent-induced forces. The second concerns the time of appearance of the viscosity surge. This is observed to follow a critical law, with an exponent independent of polymer concentration and solvent perturbation. The third concerns the inverse-power-law dependence of the viscosity peak value on shear. When the shear is scaled with an appropriate relaxation time, related to the overall interdomain structure generated by spinodal demixing, all data fall on a master curve, independent of polymer concentration, quenching depth, and solvent perturbation. This allows assigning the observed viscosity behavior to distortion and rupture of the overall interdomain structure generated by spinodal demixing.