Enhanced Electromechanical Performance of Natural Rubber Composites via Constructing Strawberry-like Dielectric Nanoparticles

Abstract

Dielectric elastomer actuators (DEA) were widely applied in the field of sensors, artificial muscles, and microrobotics as they can convert electrical energy into mechanical energy. In this work, we have designed strawberry-like barium titanate/tannic acid-ferric ion/silver (denoted as BT/TA-FeIII/Ag) dielectric nanoparticles to improve the electromechanical performance of natural rubber (NR)-based composites. In the first instance, BT nanoparticles were modified by TA by introducing catechol- and pyrogallol-type phenols, which can be complexed with FeIII to form a coating of TA-FeIII on the surface of the BT nanoparticles (denoted as BT/TA-FeIII). Then, Ag nanoparticles were deposited on the surface of BT/TA-FeIII by the reduced Ag+ via an electroless plating method. The addition of BT/TA-FeIII/Ag nanoparticles in the NR matrix enhanced the electromechanical sensitivity of NR-based composites and thus increased the actuation strain of NR-based composites. In addition, the discontinuous silver layer deposited on the surface of BT/TA-FeIII/Ag nanoparticles maintained good insulation of NR-based composites. In the final step, a high actuation strain (15.3%) was achieved by NR-based composites filled with 10 phr BT/TA-FeIII/Ag at a low electrical field (62.2 kV/mm), which was about 2.2 fold larger than the actuation strain of the pure NR (about 7.0% at 54.7 kV/mm). Overall, this strategy could provide insights for the preparation of dielectric elastomers with high actuation strain driven by a low voltage.

Constructing “sesame‐biscuit” structured hybrids with SiC and Ag particles for enhancing thermal conductivity and dielectric constant of elastomer composites

“…28 For SiC-P-Ag particles, the pronounced peaks at 368-374 and 572-604 eV were ascribed to the Ag 3d and Ag 3p states, respectively. 29 Moreover, the Ag 3d 5/2 and Ag 3d 3/2 peaks appeared at the binding energies of 368.2 and 374.3 eV, meaning that the Ag + ions were reduced to Ag nanoparticles and anchored to the surface of SiC-P. 30,31 Figure 5 displays the HR-TEM images of SiC, SiC-P, and SiC-P-Ag particles. Compared with the raw SiC particles (Figure 5A), the SiC-P particles exhibited an amorphous layer with a thickness of about 2.5 nm (Figure 5B), indicating the formation of a uniform PDA coating.…”

“…For SiC‐P‐Ag particles, the pronounced peaks at 368–374 and 572–604 eV were ascribed to the Ag 3d and Ag 3p states, respectively 29 . Moreover, the Ag 3d 5/2 and Ag 3d 3/2 peaks appeared at the binding energies of 368.2 and 374.3 eV, meaning that the Ag + ions were reduced to Ag nanoparticles and anchored to the surface of SiC‐P 30,31 …”

The role of chemical microstructures and compositions on the actuation performance of dielectric elastomers: A materials research perspective

“…In contrast to the usual mixing technique of incorporating the BT filler, a strawberry‐like barium titanate/tannic acid‐ferric ion/silver (BT/TA‐Fe III /Ag) nanoparticles were incorporated to the NR matrix to yield enhanced electromechanical response. [ 133 ] The abundance of hydrophilic groups in tannic acid (TA) led to its self‐polymerization followed by the adhesion on the BT surface in presence of a tris buffer at room temperature. The catechol groups of TA while reacting with Fe III yielded a stable five membered ring.…”

Advanced Acrylate Dielectric Elastomers with Large Actuation Strains at Very Low Electric Field

“…or conductive particles (graphene, carbon nanotubes, and Ag, etc.) into an elastomer matrix or grafting polar groups onto the molecular chains of an elastomer can improve the dielectric constant, − while often accompanying the degradation of other properties, such as increasing Young’s modulus, electrical losses, and viscoelasticity and decreasing breakdown field strength. − Furthermore, the method of addition fillers usually needs a relatively complex preparation process and is time-consuming, which is harmful to the mass production. Thus, it is still a challenge for design and preparation of high quality DEs.…”