Polyelectrolyte-based electrorheological materials

Electrorheological (ER) fluids are a kind of smart materials whose viscosity can be adjusted by electric fields, which have wide application in the field of electrical-mechanical conversion. However, the practical application of ER fluids is still limited by insufficient performance. Polyelectrolyte-based ER materials have relatively high ER effect due to their large polarizability, good dispersion stability due to their low density, and small wear due to their low hardness, which are frequently studied as one of the most promising ER materials. This review introduces the research progress of ER materials, especially polyelectrolyte-based ER materials. The synthesis methods and ER properties of three types of polyelectrolyte ER materials are introduced, including traditional polyelectrolytes, polyether polymer electrolytes and recently developed poly(ionic liquid) (PIL) polyelectrolytes. In particular, the advantages of poly(ionic liquid)s in the development of high-performance anhydrous polyelectrolyte ER materials are highlighted, and the relationship between the intrinsic structure and ER property of PIL ER materials is discussed in detail in order to guide the material design. Finally, we propose the remaining challenges and possible developments in this field for the future outlook.