Silica nanoparticle decorated polyaniline nanofiber and its electrorheological response

We fabricated polyaniline nanofibers (PANIFs) with an average diameter of 350 nm through an interfacial polymerization by using dodecylbenzylsulfate acid as a dopant, and then examined their electrorheological (ER) characteristics. Silica modification was carried out in ethanol/water solution via a modified Stober method, and successful location of the silica nanoparticles on the surface of PANIF was confirmed by both scanning electron microscope (SEM) and transmission electron microscope (TEM) images. Thermogravimetric analysis (TGA) showed enhanced thermostability of the modified nanofibers. ER tests including flow curve and amplitude/frequency sweeps, which were performed by a rotational rheometer, demonstrated that the nanosilica modified PANIF exhibits higher ER effect than pure PANIF. In addition, the resultant flow curves are fitted well by Cho-Choi-Jhon model rather than Bingham model, while the yield stresses of both ER fluids versus electric field strengths are fitted well into a single line by the universal yield stress equation.