Research of frequency dependence on dielectric properties of VHB4910 dielectric elastomer

Dielectric elastomers (DE) are emerging electroactive polymer used in high performance applications such as actuators and sensors for its electromechanical coupling performance, DE can generate large mechanical deformation under electrical stimulation, the acrylic 3M VHB4910 series are most popular DEs. The electrical parameter of the material, e. g. dielectric constant, is key parameter which determines its electromechanical coupling application. However, so far by our knowledge, there is still some controversy over the dielectric constant of VHB4910; especially its relevance to the frequency, what is more there is not a very good theoretical mechanism analysis. In this paper, using the Broad Band Dielectric Spectrometer (BDS), we present an experimental study relating to variation in the dielectric constant of VHB 4910 over wide frequency band (10 ^-2~ to 10 ⁷ Hz). The results demonstrated that dielectric constant of VHB4910 has a weak dependence of low frequency and become much more relevant on high frequency, the value of the dielectric constant in low frequency is 4.8. Then from the microcosmic view, the mechanisms of orientation polarization polarizability explain the behavior in frequency of this parameter. After that, the characteristic of Debye and Cole - Cole equation was analyzed. Compared to the experimental results, Cole - Cole equation was more suitable to describe the mechanism of the dielectric properties of VHB4910. Finally, the mathematical model of dielectric properties of VHB4910 was obtained from the fitted result by Cole - Cole model.