Formamide-modified titanium oxide nanoparticles with high electrorheological activity

TiOx-based nanospheres modified by formamide (FA) as dielectric particles for electrorheological (ER) fluids were successfully synthesized through simple sol-gel hydrolysis and self-assembly. The suspension containing TiOx-FA displays superior ER activity, with a yield stress of 148 kPa (at 5 kV mm(-1)) under a DC electric field, which is 10 times that of ER fluids containing pure TiOx nanoparticles. More importantly, comparison between the FA and N,N-dimethylformamide (DMF) as the shell structure indicated that the ER performance was positively correlated with the dielectric constant of the polar molecule shell. The result represents a critical step towards an in depth understanding the enhancement effect of polar molecules. This study can afford a new strategy to achieve optimal performance in ER fluids.