Simple and accurate determination of sol–gel phase transition point using disk-type electromagnetically spinning viscosity measurement system

Abstract

We performed viscosity measurements with ultrahigh sensitivity by combining our original electromagnetically spinning technique and a newly developed floating disk probe. This system is, in principle, a torque-control-type viscometer with a noncontact function that can apply an arbitrary low torque, and therefore, enables us to clearly distinguish between liquids and solids from the viewpoint of the mechanical property of materials. In our measurements, we examined the difference in the thermoreversible sol–gel transition of a methylcellulose solution to determine the precise transition points, and successfully observed the hysteresis behavior of the gelation and solation processes.

Application of EMS system for continuous measurement of rheology in reaction chamber

“…22) The electro-magnetically spinning (EMS) viscoelasticity measurement system developed in this study has the advantage that the rotational probe can be confined inside the closed reaction chambers of the aforementioned processes, because the driving torque is remotely conducted to the rotor from outside the chamber. [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] The driver applies a rotating magnetic field to the space around the rotor, which is made of electrically conductive materials. The interaction between the rotational magnetic field and induced Lorentz current generates torque, which rotates the probe such that it follows the rotation of the magnetic field.…”

Introduction to rheometry for researchers of ultrasonics

“…In this section, a unique method of viscosity measurement is introduced. [34][35][36][37][38][39][40][41][42][43][44][45][46][47] It belongs to the rotational type, but the probe and the main body of the viscometer are separated. The probe is driven remotely through electromagnetic interaction.…”

Extension of remote distance of electromagnetically spinning viscometer

“…Many types of rheometry methods exist, 16) and we are extending various methodologies for the unique rotationaltype viscosity meter developed by us, [17][18][19][20][21][22][23][24][25][26][27][28][29] i.e. an electromagnetic spinning (EMS) viscometer that provides an accurate measurement of the low viscosities of aqueous salt solutions having a shear viscosity as low as that of pure water.…”