Ferrofluid viscometer

Publisher Website
Google Scholar
Abstract
The alignment of magnetic colloidal particles along a magnetic field induces a birefringence of the solution. As the magnetic field is switched off, this birefringence level relaxes to zero with a characteristic time proportional to the viscosity of the solution. The measurement of this relaxation time gives the value of the viscosity with a relative accuracy of 5 % and over a viscosity range of seven decades