Enhanced Electrorheological Properties of PMMA–Titanium Oxide Nanocomposites

Abstract

The electrorheological (ER) effect is crucial for development of responsive materials controlled by electric fields. To exploit the ER effect for designing better phase-change materials with improved shear resistance at elevated temperatures, polymers may be employed as the matrix in functional composites with high-dielectric fillers. Here we demonstrate enhanced ER properties of PMMA–TiO2 nanocomposites, at temperatures up to 200 °C. The influence of temperature, volume fraction, and electric field strength on the rheological properties including flow curves, modulus sensitivities, and temporal response was investigated by a rotational rheometer with electric field accessories. The observed temporal response under a fixed electric field, bearing strong resemblance to the creep and recovery in mechanical testing, quantitatively matches the description by a viscoelastic model. These results may provide solid evidence for a potential route to develop responsive materials.

Suppressed physical aging in PMMA‐titanium oxide nanocomposites by controlling alignment of nanoparticles

“…We manipulated the aggregation of NPs using a direct-current (DC) electric field to form micron-scale patterns and measured the viscoelastic response during aging of the nanocomposite. 19 Applying electric field is not only an easy and cheap method to align electrical sensitive fillers, 20 and can also facilitate the annihilation of defects. 21 This rearrangement of NPs under electric fields changes the size, type, and distribution of interfaces between the NPs and polymer matrix, thus altering the confinement conditions of the polymer at the nano-or micro-length scale.…”

“…In this study, we investigated the structural relaxation of polymer nanocomposites with NPs of fixed loading but different morphologies. We manipulated the aggregation of NPs using a direct‐current (DC) electric field to form micron‐scale patterns and measured the viscoelastic response during aging of the nanocomposite 19 . Applying electric field is not only an easy and cheap method to align electrical sensitive fillers, 20 and can also facilitate the annihilation of defects 21 .…”