TEMPERATURE EFFECTS OF DIELECTRIC-PROPERTIES OF ER FLUIDS

Under the consideration of the role that energy transfer and dissipati on play in ER effect, an improved theory fame for ER effects, polariza tion-dissipation-structure-rheology is suggested. The theory frame is substantiated by the basic physical laws and certain critical experime ntal facts. The dielectric response of a diatomite ER fluid to tempera ture is measured in the temperature range of 140 K to 400 K. By compar ison of the DC conductivity with the AC effective conductivity of the sample, we found that the AC dielectric loss consists of two parts. On e part comes from the DC conductivity, the other from the response of the bound charges in scope of particle to AC field. It is suggested th at the response of bound charges is very important to ER effects. Besi des, the effect of temperature on shear stress is measured, and interp reted based on the dielectric measurements. The source of two loss pea ks in the curve of the dielectric loss versus temperature is not clear .