High-Frequency Rheo-Optical Spectroscopy by Ultrasonically Induced Light Diffraction

Abstract

We improved the apparatus for measuring frequency-dependent complex strain-optical coefficient using ultrasonically induced depolarized light diffraction. Measurements were performed at frequencies from 5 to 75 MHz. The upper frequency limit is three times larger than that obtained in our previous study. We also measured shear relaxation spectra at frequencies from 5 to 205 MHz and compared the results with strain-optical coefficients of 4-cyano-4 0 -pentylbiphenyl (5CB). The resulting spectra suggest that 5CB has second a relaxation at a high frequency, which has not been observed by heterodyne dynamic light scattering. #

Rapid measurement of ultrahigh viscosity using an electro-magnetically spinning system

“…[3][4][5] The accurate measurement of the viscosity is of course important also for the wide field of ultrasonic spectroscopic study on the soft materials. [6][7][8][9][10][11] We developed a new type of a viscometer using the electro-magnetically spinning (EMS) method, [12][13][14][15][16][17][18][19] which is already commercially available as an industrial apparatus. In the EMS method, a remote torque is applied to a spherical metal probe in the sample in a non-contact manner; therefore, it is free from contamination when using a disposable sample cell.…”