Comment on “Preparation and electrorheological properties of polyquin(2,3-b)acridine-12,14(5,7)dione-based suspensions”

We comment on the flow behavior of electrorheological (ER) fluids, based on polyquin(2,3-b)acridine-12,14(5,7)dione (polyquinacridinedione, PQA) dispersed either in bromodiphenylmethane (BDPM) or silicone oil under two different applied electric fields of 2 and 3 kV/mm. Our proposed shear stress model (Cho-Choi-Jhon (CCJ) model) not only fits the flow curves of PQA based ER fluids, but also provides a better explanation on their flow properties compared with both Bingham fluid model and De Kee-Turcotte model. Especially, we are able to fit the shear stress decrease at low shear rate.