Synergetic improvement of dielectric properties and thermal conductivity in Zn@ZnO/carbon fiber reinforced silicone rubber dielectric elastomers

Dielectric elastomers (DEs) with large dielectric permittivity (ε') but low loss, high thermal conductivity (TC), are highly pursued in artificial muscles. To elevate the ε' and TC of raw zinc (Zn)/silicone rubber (SR), raw Zn particles were oxidized to Zn@ZnO (zinc oxide), and then incorporated into SR. Compared to raw Zn/SR, the Zn@ZnO/SR showcases the enhanced ε' and TC because the ZnO interlayer induces intraparticle polarization and promotes interfacial phonon transport. Further, synergetic improvement of ε' and TC is found when modicums carbon fibers (CF) was added into Zn@ZnO/SR. The ε' and TC of Zn@ZnO/CF/SR are 23.83 and 1.53 W/(m·K), corresponding to 3.41 and 0.48 W/(m·K) for raw Zn/SR at 60 phr fillers. However, dielectric loss and electric conductivity of Zn@ZnO/CF/SR are remained at low levels. This work provides a strategy for design and preparation of robust SR DEs with high ε' and TC but low loss for prospective applications.