High breakdown-strength composites from liquid silicone rubbers

Abstract

In this paper we investigate the performance of liquid silicone rubbers (LSRs) as dielectric elastomer transducers. Commonly used silicones in this application include room-temperature vulcanisable (RTV) silicone elastomers and composites thereof. Pure LSRs and their composites with commercially available fillers (an anatase TiO 2 , a core-shell TiO 2 -SiO 2 and a CaCu 3 Ti 4 O 12 filler) are evaluated with respect to dielectric permittivity, elasticity (Young's modulus) and electrical breakdown strength. Film formation properties are also evaluated. The best-performing formulations are those with anatase TiO 2 nanoparticles, where the highest relative dielectric permittivity of 5.6 is obtained, and with STX801, a core-shell morphology TiO 2 -SiO 2 filler from Evonik, where the highest breakdown strength of 173 V μm −1 is obtained.

Simultaneously improved actuated performance and mechanical strength of silicone elastomer by reduced graphene oxide encapsulated silicon dioxide

“…Therefore, a key issue is to increase the k of DEs, while retaining other excellent properties such as low dielectric loss, low modulus (Y), and good flexibility. One common method to obtain a DE with high k is to introduce high-k ceramics such as TiO 2 into the elastomer matrix [10,[15][16][17]. Usually, a high content (up to 50 vol%) of ceramics is required to obtain high k, leading to low flexibility and poor processability, and thus largely limiting the wide application of DEs [18].…”

Silicone rubbers for dielectric elastomers with improved dielectric and mechanical properties as a result of substituting silica with titanium dioxide

“…[20] Both surfaces of films were metallized with silver 100 nm-thick electrodes (width 30 mm × length 90 mm). Conductive electrode tapes were attached to make a connection with the high voltage amplifier.…”

“…Moreover, the breakdown results shown in Figure 3 suggest that the resistance of the elastomers to dielectric breakdown is enhanced by an increase in the Young's modulus (as seen in Table 3), which has been reported in previous work on polyethylenes [24] and LSR elastomers. [20] 3.2. LSR-TiO 2 formulations LSR materials enable a fast curing process, and the resulting elastomers possess favorable dielectric strengths and mechanical properties -as seen from studies in this work and in previous work.…”

“…LSR-TiO 2 formulations LSR materials enable a fast curing process, and the resulting elastomers possess favorable dielectric strengths and mechanical properties -as seen from studies in this work and in previous work. [20] XLR with the overall best properties for mixing in particles is chosen Table 3.…”

“…[19] It was shown in our previous study that titanium dioxide (TiO 2 ) nanoparticles increase both the dielectric permittivity and breakdown strength of LSR formulations. [20] The rutile TiO 2 exhibits a higher dielectric constant (ε r~1 10) than the anatase TiO 2 (ε r~4 5), which therefore makes it a good candidate for achieving higher nanocomposite elastomer permittivity. [21] Several other studies on similar systems have been conducted but without varying the silica content as the commercial elastomers do not usually provide such handle.…”