Electrorheological fluid

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Electrorheological (ER) fluids are suspensions of extremely fine non-conducting but electrically active particles (up to 50 micrometres diameter) in an electrically insulating fluid. The apparent viscosity of these fluids changes reversibly by an order of up to 100,000 in response to an electric field. For example, a typical ER fluid can go from the consistency of a liquid to that of a gel, and back, with response times on the order of milliseconds.^[1] The effect is sometimes called the Winslow effect after its discoverer, the American inventor Willis Winslow, who obtained a US patent on the effect in 1947^[2] and wrote an article published in 1949.^[3]

^ Khanicheh, Azadeh; Mintzopoulos, Dionyssios (June 2008). "Evaluation of Electrorheological Fluid Dampers for Applications at 3-T MRI Environment" (PDF). IEEE/ASME Transactions on Mechatronics. 3. 13 (3). et al: 286–294. doi:10.1109/TMECH.2008.924043. S2CID 14188698. Archived from the original (PDF) on 2014-07-22. Retrieved 2016-10-12.
^ U.S. patent 2,417,850: Winslow, W. M.: 'Method and means for translating electrical impulses into mechanical force', 25 March 1947
^ Winslow, Willis M. (1949). "Induced fibration of suspensions". J. Appl. Phys. 20 (12): 1137–1140. Bibcode:1949JAP....20.1137W. doi:10.1063/1.1698285.