Titanium Dioxide Nanoparticles Modified with Disulfonic Acid Functionalized Imidazolium Ionic Liquids for Use as Electrorheological Materials
Zhenjie Zhao, Yuting Yin, Xiao Jin, Guangchen Zhang, Li‐Min Wang, Ying Dan Liu, Hyoung Jin Choi
Abstract
A disulfonic acid functionalized ionic liquid, 1,3-disulfonic acid imidazolium chloride ([Dsim]Cl), was synthesized and utilized to prepare TiO2-based ionogel nanoparticles (TiO2-[Dsim]Cl) using a precipitation method. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy showed that the [Dsim]Cl molecules were introduced into the TiO2 matrix through electrostatic force between [Dsim]Cl and Ti atoms. The EDS mapping analysis indicated that the elements of [Dsim]Cl were distributed inside and on the surface of the TiO2-[Dsim]Cl nanoparticles. The electrorheological (ER) properties of TiO2-[Dsim]Cl ionogel nanoparticles and pure TiO2 were evaluated under the same conditions. The ER properties of the TiO2-[Dsim]Cl nanoparticles were found to be closely related to the content of [Dsim]Cl. Dielectric analysis demonstrated that adding an appropriate amount of [Dsim]Cl can enable the TiO2 nanoparticles to have a higher polarizability and a suitable relaxation time, both of which can significantly enhance the ER effect of the TiO2-[Dsim]Cl nanoparticles. More significantly, the TiO2-[Dsim]Cl nanoparticles exhibited a stable yield stress over a wide temperature range from 5 °C to 85 °C, indicating the high thermal stability of the TiO2-[Dsim]Cl ionogel nanoparticles.