Electro-optical Kerr effect in HFE-7100

This work is an experimental study on electrooptical Kerr effect in hydrofluoroether HFE-7100. It is part of a scientific project aiming to better understand electrohydrodynamic (EHD) behavior and hence optimize EHD systems. The electro-optical Kerr effect is a nonintrusive method that allows to study the development of charged layers at the electrode/liquid interface. In this paper, the authors examine the applicability of the Kerr effect method on HFE-7100, a dielectric liquid that has proven to be very efficient in EHD applications. The system consists of a monochromatic green laser source and a rectilinear polariscope. The Kerr cell has two planar electrodes on which a high sinusoidal voltage is applied. The light intensity of the obtained images is then analyzed. The Kerr coefficient value B of the HFE-7100 is deduced to be $\mathrm{B}= 2.7 \times 10^{-14}\mathrm{V}/ \mathrm{m}^{2}$, a value that is comparable to that of purified water. Kerr images are presented, and their qualitative analysis demonstrates the presence of space charge. This work proves that HFE has a good sensitivity to the Kerr effect.