TiO₂ Nanoparticles Dual-Modified with Ionic Liquid and Acetic Acid for Use as Electrorheological Materials to Achieve Ultrahigh and Stable Electroresponsive Performances

Abstract

TiO2 nanoparticles modified by ionic liquid (IL), which are called inorganic ionogels, have shown improved electroresponsive electrorheological (ER) characteristics due to the contribution of IL to the polarizability and conductivity of the nanoparticles. However, the IL on the particle surface readily generates a large current density under high-strength electric fields, limiting the further application of IL-containing electroresponsive materials. In this study, 1, 3-disulfonic acid imidazolium chloride ([Dsim]Cl) ionic liquid and acetic acid (AA) dual-modified TiO2 nanoparticles (TiO2-[Dsim]Cl-AA) were fabricated to solve this problem without significantly reducing the ER properties of the nanoparticles. The morphologies and structures of the TiO2-[Dsim]Cl-AA nanoparticles modified with different amounts of AA were synthesized and investigated. The rheological analysis indicated that the TiO2 ionogel nanoparticles modified by an appropriate amount of AA can effectively reduce the leakage current density of the ER fluid. With a relatively low particle volume fraction of 25%, the ER fluid showed ultrahigh yield stress up to 128 kPa and low zero-field viscosity of 7 Pa·s. In addition, the ER fluid also showed a stable ER effect in a broad temperature range of 5–85 °C and a slow sedimentation rate with time. The IL and AA dual-modified TiO2 nanoparticles with an ultrahigh yield stress, broad working temperature range, and high antisettling stability will be excellent ER candidates for practical application.

Ionic liquid-modified TiO 2 nanoparticle-filled polyurethane as a new electro-responsive elastomer with controlled modulus and actuation strain by an electric field

“…S2c), the stretching vibration of carboxylic group in AA can be observed at 1535 and 1446 cm − 1 . The hydrophobic methyl groups in the outer layer of TiO 2 -IL-AA particles [33] have a good a nity with the PU matrix, increasing the dispersibility of the particles in PU.…”

“…As a comparison sample, pure PU elastomers were prepared by the same experimental steps without adding nanoparticles. To observe the effect of the chemical structure of the particle surface, the TiO 2 nanoparticles modi ed by both IL and acetic acid (AA) (TiO 2 -IL-AA) [33] were also applied as the dispersed phase of EREs. Schematic fabrication process of the EREs and the chemical reaction mechanism of PU are shown in Scheme 1.…”

Engineering Conductivity and Performance in Electrorheological Fluids Using a Nanosilica Grafting Approach

“…Electrorheological (ER) fluids are systems whose rheological parameters can be controlled via an external electric field. These systems of ER fluids are generally heterogeneous systems composed of a dispersed particulate phase and a nonconducting liquid medium. − The formation of chain-like structures from the particles within the liquid medium upon the application of an external electric field, called the “ER effect”, leads to an abrupt change in the rheological parameters of the system, and the systems then commonly exhibit a certain yield stress, τ y , that can be defined as a stress that the material can withstand before it starts to flow. This behavior can be utilized in many applications. , …”