Preparation and characterization of phosphate cellulose-based electrorheological fluids

Full Paper: Phosphate cellulose particles were synthesized via the phosphor ic ester reaction of cellulose particles, phosphoric acid and urea, with va rious molar concentrations of the phosphoric acid, and then dispersed in si licone oil to produce anhydrous dry base electrorheological (ER) fluids. Th e effect of the phosphoric ester reaction on ER properties was examined und er various applied electric field strengths. An ER system with phosphate ce llulose particles formed in a 2.0 M phosphoric acid solution exhibited the highest yield stress (ER performance) via rheological measurements under bo th controlled shear rate and shear stress modes. A difference in the flow b ehavior of the phosphate cellulose-based ER fluids prepared from different molar concentrations of phosphoric acid solution was also investigated via the dielectric spectra. It was found that the interfacial polarization mech anism provides an accurate description of the ER characteristics of phospha te cellulose-based ER fluids. [GRAPHICS] Static yield stress vs. electric field strength measured from the CSS mode for phosphate cellulose ER fluids-treated with a various phosphoric acid co ncentrations (particle concentration: 10% (v/v) in silicone oil).