Abstract
Thermally excited surface waves were measured on gelatin gel in a frequency range up to 800 kHz by a newly developed technique of light scattering. The observed frequency and dispersion showed that the wave propagating on the gel is a surface tension wave, not a surface elastic wave, in spite of the elasticity appearing in the sol-gel transition. The surface tension of the gelatin gel at 3.0 wt% and 20°C was observed from the frequency to be 32 mN/m. The shear viscosity of sol and gel determined from the damping constant over a wide frequency range suggested the existence of a relaxation process characteristic to each phase.