Poly(ionic liquids)s (PILs) in silicone oil (SO) response to the externally applied electric field without the need for any hydrophobic and polar activators. The aim of this study is to investigate electrorheological (ER) properties of a PIL including phosphorus atom and to improve its ER activity by preparing composites with halloysite (HNT) and graphene oxide (GO). The phosphonium-based PIL (PPIL, Poly[trimethyl(4-vinylbenzyl)phosphonium trifluoromethane sulfonate]) structure was designed to contain short alkyl groups and organic counterions to achieve high ER activity. To determine the optimum amount of PPIL in SO, dielectric and ER flow curves of various weight percentages (5, 10, 15, and 20 wt.%) were inspected. The highest polarization and electric field induced yield stresses were obtained for 20 wt.% PPIL/SO system. Then, its covalently bonded composites were engineered with 20% by weight of HNT and HNT/GO. The dielectric and ER flow properties of PPIL/SO, HNT/PPIL/SO, and HNT/GO/PPIL/SO suspension systems were compared, and revealed that the introduction HNT improved the ER response time whereas GO enhanced the electric field induced polarizability of PPIL. The viscoelastic properties of the suspensions investigated under various electric field strengths showed that the highest electric field induced elastic modulus and creep-recovery% were obtained for HNT/GO/PPIL/SO system. On the other hand, the stable viscoelastic properties were observed only for HNT/PPIL/SO suspension system at elevated temperatures.  
 

electrorheology,poly(ionic liquid),halloysite,graphene oxide