2019 年 23 巻 1 号 p. 15-18
The ultrasonic velocities in a colloidal solution and a thixotropic hydrogel containing imogolite are measured. Our original experimental setup can detect the change of ultrasonic velocity caused by the mixing of imogolite and maleic acid in pure water. Using this setup, the ultrasonic velocity is found to remain unchanged during the macroscopic solid/liquid transition and viscoelastic change of a thixotropic hydrogel consisting of imogolite and maleic acid, which is consistent with previous literatures. Thus, the ultrasonic velocity measurement proves to be effective for the detection of well-dispersed clay minerals in diluted state, regardless of the phase and viscoelastic change of substances.