The electrical breakdown strength of pre-stretched elastomers, with and without sample volume conservation

Abstract

In practice, the electrical breakdown strength of dielectric electroactive polymers (DEAPs) determines the upper limit for transduction. During DEAP actuation, the thickness of the elastomer decreases, and thus the electrical field increases and the breakdown process is determined by a coupled electro-mechanical failure mechanism. A thorough understanding of the mechanisms behind the electro-mechanical breakdown process is required for developing reliable transducers. In this study, two experimental configurations were used to determine the stretch dependence of the electrical breakdown strength of polydimethylsiloxane (PDMS) elastomers. Breakdown strength was determined for samples with and without volume conservation and was found to depend strongly on the stretch ratio and the thickness of the samples. PDMS elastomers are shown to increase breakdown strength by a factor of ∼3 when sample thickness decreases from 120 to 30 μm, while the biaxial pre-stretching (λ = 2) of samples leads similarly to an increase in breakdown strength by a factor of ∼2.5.

The influence of static pre-stretching on the mechanical ageing of filled silicone rubbers for dielectric elastomer applications

“…Table 1 in SI), as breakdown strengths were proved previously to be strongly dependent on the thicknesses of elastomeric films [37], i.e. the thicker PDMS films show low breakdown strength compared to the thin films, due to the increased volume -and thus larger number of defects.…”

“…Since the film thickness of silicone elastomers has been shown to influence strongly electrical breakdown strengths [37] and mechanical properties [39], two thicknesses for each film were investigated, i.e. each elastomer formulation was tested in four configurations at each timespan (thick or thin/60% or 120% prestretch), while for the breakdown strength measurements another two configurations were utilised (either non-stretched or stretched to the utilized pre-stretch during the measurement).…”

“…The breakdown measurements were also performed on the stretched films, which were prestretched based on the procedure described in Zakaria et al [37] and as shown in Figure 3. …”

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

“…[32,33] The fitted data is shown in Table 2. For the elastomers the XLR is by far the best performing elastomer with respect to electrical reliability.…”

Monolithic PDMS Laminates for Dielectric Elastomer Transducers through Open-Air Plasma Treatment

“…For thicker films the removal of the excessive heat is slower than for thinner films, which subsequently will decrease breakdown strength as conductivity increases in line with increased temperature [27] . Zakaria et al [27] measured breakdown strength for samples as single films with various thicknesses as well as samples consisting of multiple layers and showed that breakdown strengths of thicker single films decreased by 43% and the multiple layer samples decreased by 31%. In comparison, the plasma-treated films in this study decreased by only 6% in breakdown strength, which…”