Orientation of particles in an electrorheological fluid under an electric field

The orientation of the particles in an electrorheological fluid under an electric field has been studied. Triglycine sulfate (TGS)-wax mixtures were applied in this study. Here the TGS particles are in the ferroelectric phase with spontaneous polarization p(s) in the <010> direction at below the Curie temperature T(C) and become paraelectric without a permanent electric moment at above T(C). By measuring x-ray-diffraction intensities of TGS/wax samples under an electric field at below and above T(C), respectively, it is found that the particles with spontaneous polarization turn their p(s) vectors to the direction of the external electric field in addition to forming chains or columns. However, the particles without permanent moment only form chains or columns, in which no preferred orientation of the particles can be observed. The preferred orientation degree is determined by comparing the diffraction intensity in these two cases.