electrorotation

Electrorotation is a phenomenon observed when asymmetric polarizable particles suspended in a conductive fluid are subjected to a rotating electric field. This applied field causes the particles to rotate. The direction and speed of rotation depend on the electrical properties of the particle and the surrounding fluid, as well as the frequency of the applied electric field.

The mechanism behind electrorotation involves the interaction of the electric field with the induced dipoles of the particles. As the electric field rotates, it drags these induced dipoles along, causing the particles to spin. The specific electrical properties, such as conductivity and permittivity, at the particle-fluid interface play a crucial role in determining the magnitude and phase of the induced dipole.

Electrorotation is a sensitive technique that can be used to characterize the electrical properties of cells and other microscopic objects. By analyzing the rotational behavior of particles at different electric field frequencies, researchers can gain insights into their membrane properties, internal composition, and overall health. This technique has found applications in various fields, including cell biology, diagnostics, and microfluidics, for tasks such as cell sorting, manipulation, and analysis of biological samples. The phenomenon is distinct from electrophoresis, which involves the translational motion of charged particles in an electric field.