Effects of Ferroelectric Fillers on Composite Dielectric Elastomer Actuator

Abstract

Integrating nano- to micro-sized dielectric fillers to elastomer matrices to form dielectric composites is one of the commonly utilized methods to improve the performance of dielectric elastomer actuators (DEAs). Barium titanate (BaTiO3) is among the widely used ferroelectric fillers for this purpose; however, calcium copper titanate CaCu3Ti4O12 (CCTO) has the potential to outperform such conventional fillers. Despite their promising performance, CCTO-based dielectric composites for DEA application are studied to a relatively lower degree. Particularly, the composites are characterized for a comparably small particle loading range, while critical DEA properties such as breakdown strength and nonlinear elasticity are barely addressed in the literature. Thus, in this study, CCTO was paired with polydimethylsiloxane (CH3)3SiO[Si(CH3)2O]nSi(CH3)3 (PDMS), Sylgard 184, to gain a comprehensive understanding of the effects of particle loading and size on the dielectric composite properties important for DEA applications. The dielectric composites’ performance was described through the figures of merit (FOMs) that consider materials’ Young’s modulus, dielectric permittivity, and breakdown strength. The optimum amounts of the ferroelectric filler were determined through the FOMs to maximize composite DEA performance. Lastly, electromechanical testing of the pre-stretched CCTO-composite DEA validated the improved performance over the plain elastomer DEA, with deviations from prediction attributed to the studied composites’ nonlinearity.

Additively manufactured unimorph dielectric elastomer actuators: Design, materials, and fabrication

“…Comparison of the obtained breakdown strength values with manufacturer's data is complicated because the manufacturer's values typically measured for AC voltage result in considerably smaller breakdown strength values. Nevertheless, the measured breakdown strength of 10:1 Sylgard 182 is close to similar materials across the literature (Vaicekauskaite et al, 2019;Sikulskyi et al, 2021).…”

Liquid Metal Patterned Stretchable and Soft Capacitive Sensor with Enhanced Dielectric Property Enabled by Graphite Nanofiber Fillers

“…In this work, by utilizing the unique features of the liquid metal electrode and the dielectric elastomer, we fabricated a soft and stretchable capacitive sensor. Polydimethylsiloxane (PDMS) has been widely used to fabricate dielectric elastomers by adding fillers such as graphene oxide [39], functionalized graphite oxide [40], carbon black [41,42], copper calcium titanate [43], barium titanate [44], and titanium di-oxide [45]. We also utilized PDMS to prepare dielectric elastomers with enhanced dielectric properties by dispersing graphite nanofiber (GNF) in the PDMS matrix.…”

“…Graphene Oxide 3.4-9.6 [39] 0.5 vol % PDA@SiO 2 @GO 1 ~6 [40] 6 wt % SrTiO 3 2 ~14 [76] 30 vol % Carbon Black ~6.5 [42] 4 wt % CCTO 3 6.5 [43] 20 wt % BaTiO 3 4 ~5 [44] 40 wt % TiO 2 5 ~4.5-4.9 [77] 8-10 vol % TiO 2 @SiO 2 6 ~7 [45] 16 vol % Ag@SiO 2 7 6.8 [78] 3 wt % GNF (this work) 6.41 6 wt % 1 Polydopamine modified silicon dioxide@graphite oxide hybrid. 2 Strontium titanate.…”

Electrostrictive Fiber with High Electromechanical Properties Using a Styrene–Ethylene–Butylene–Styrene-Based Dielectric Elastomer

“…34−37 Among them, SR has been regarded as a good candidate because of its good biocompatibility, excellent electromechanical properties, and fast response. 38 However, it generally requires high stimulation voltages to obtain greater filed-induced strain. 1 The main method for solving this problem is to increase the dielectric constant of the material with the addition of high-dielectric particles 39 or to reduce the Young's modulus via introducing low-molecular-weight plasticizers.…”

“…The most commonly used DE materials include acrylic elastomers, − polyurethane (PU), , and silicone rubber (SR). − Among them, SR has been regarded as a good candidate because of its good biocompatibility, excellent electromechanical properties, and fast response . However, it generally requires high stimulation voltages to obtain greater filed-induced strain .…”