Electric conductivity of the Gelatin Gel and Sol
Abstract Book of the XXIII IUPAP International Conference on Statistical Physics, Genova, Italy, (9-13 July 2007)Abstract
\ In order to study the sol-gel transition of gelatin solution, we used the dynamic light scattering from polystyrene latex spheres dispersed in gelatin solution and measured the viscosity of the solution of various gelatin concentrations.We found that the temperature dependence of the viscosity shows anomaly near the sol-gel-transition point and obeys the Vogel-Fulcher law in every solution. These experimental results motivate us to examine the physical properties of the solvent in geletin solution aroud the sol-gel transition temperature.
\ In the present study, we measure the electric conductivity of geletin solution. We use standard phosphate buffer solution of pH 6.86 as the solvent of gelatin solution. We examine the samples of which the gelatin concentrations are from about 5wt% to about 60wt%.
The electric conductivity of every solution decreases monotonously across the sol-gel transition point with decreasing temperature from about 330K to about 280K. Contrary to our expectations, the temperature dependence of the electric conductivity shows no anomaly near the sol-gel transition point.
We also obtain the gelatin concentration dependences of the electric conductivity at 283K, 293K, 303K, 313K, 323K and 333K. The concentration dependence of the electric conductivity changes at about 40wt% on each temperature.
\ We explain the temperature dependence and the concentration one of the electric conductivity of gelatin solution on the basis of bulk and bound water model.