The Effect of Nano TiO2 on Space Charge Behaviour of Silicone Elastomer Under DC Electric Field

Dielectric elastomers (DE) have aroused a lot of interest from researchers due to their huge potential for application in energy transducers. In particular, silicone elastomer stands out for its excellent characteristics such as softness and flexibility, heat resistance, chemical resistance and insulation properties. The permittivity of most silicone elastomers is relatively small (less than 3), which often does not meet the high capacitance requirements of energy transducers. It is common to improve the permittivity of dielectrics through adding fillers with high permittivity, which will not only change the polarization properties but also the charge transport of the material. Under high dc field, space charge may accumulate in the dielectric, distorting the electric field and thus affecting the breakdown properties of the dielectric. In this paper, different contents of nano-sized TiO2 (5, 10 and 15 phr) were added into PDMS (Sylgard 184) to study the space charge behavior of silicone/TiO2 composites by the PEA measurement system. The effects of space charge accumulation on the dielectric properties of silicone elastomer are discussed. The results show that compared with the PDMS without fillers, the permittivity of PDMS with nano-TiO2 is increased in the low frequency region, the dielectric loss is decreased, the accumulation of heterocharge near the anode is strongly reduced and the higher the filler concentration, the lower the maximum electric field distortion.