Dynamic light scattering study on gelatin aqueous solutions and gels

Abstract

The sol–gel transition of gelatin aqueous solutions has been investigated by dynamic light scattering as a function of gelatin concentration, C, at 10 °C, by taking account of the nonergodic nature of gels. The sol–gel transition concentration, Cgel, was determined to be around 0.35 wt % in this particular case. The scattered intensity exhibited a speckle pattern for C>Cgel. The dynamic component of the scattered intensity, 〈IF〉T, was successfully extracted from the time-average scattered intensity, 〈I〉T. 〈IF〉T diverged at Cgel and decreased by further increasing C. The time-intensity correlation function exhibited a power-law behavior exclusively at C≈Cgel. The exponent was found to be independent of the scattering vector, as it should be as a critical exponent of connectivity.