1991 Fiscal Year Final Research Report Summary
Studies of critical dynamic in a micellar solution
Grant-in-Aid for General Scientific Research (C)
|Allocation Type||Single-year Grants |
|Research Institution||GUNMA UNIVERSITY |
HAMANO Kenzi Gunma University, Faculty of Technology, Associate Professor, 工学部, 助教授 (00143199)
|Project Period (FY)
1990 – 1991
|Keywords||Surfactant solution / Critical phenomena / Critical-point universality / Rotational viscometer / Non-Newtonian viscosity / Phase separation / Light scattering / Shear-rate dependence|
In this work we have investigated critical dynamics for a nonionic micellar solution in the presence of shear flow by comparing with those for a binary liquid mixture of isobutyric acid in water from viewpoint of critical-point universality. The results obtained in this work have been summarized below.
(1)The estimated value of 0.02 for the exponent, which characterizes the shear-rate dependence in the critical viscosity near the critical mixing point of tetra-ethylene glycol n-decylether in water, has been found to agree well with the theoretical prediction of Onuki and Kawasaki.
(2)We have examined the non-Newtonian behavior in the viscosity in terms of the shear rate and the life time of critical fluctuations. The measured viscosities near the critical point have been found to obey a universal-like function with a dimensionless variable.
(3)We have estimated experimentally a characteristic temperature associated with shear from lightscattering observation inside the coexistence curve. The shear-rate dependence of the temperature for both system here has been found to agree well with the theoretical prediction of Onuki and Kawasaki. We have, interpreted this temperature as to be the crossover one between the shearaffected to, the. shear-unaffected regime inside the coexistence.
(4)We have observed in the measured viscosity two regions of shear-thining and shear-thicking, separated by the characteristic temperature.
(5)We have investigated the viscosity behavior as a function of time in a phase-separating mixture of isobutyric acid in water using a pressure-jump technique. A significantly large enhancement in the viscosity has been observed in a rather deep-quench under a low shear-rate.
(6)The dynamics of spinodal decomposition has been examined for a shear-sensitive micellar solution in terms of a universal function for a fluid by a shear quench, in which the shear rate is dropped to zero inside the coexistence curve.
Research Products (22results)