Self‐adaptive electrostatic discharge performance of ZnO microvaristors doped silicone rubber composites

With the increase in applied voltage and the decrease in volume, integrated electronic modules have become electrostatic sensitive. ZnO microvaristors doped silicone rubber (SiR) composite, with electric field-dependent conductivity, shows promising prospects for solving the electrostatic problem. In this study, 20 vol% to 50 vol% ZnO/SiR composite films, filled with 10–30 μm ZnO microvaristors, were prepared and put into the test of electrostatic discharge. Compared with the insulating and conducting materials, ZnO/SiR composites achieve the lowest initial voltage and a short time constant of electrostatic discharge. With the increase of ZnO microvaristors volume fraction, from 20% to 50%, the initial voltage and the time constant of electrostatic discharge drop from 1.78 to 0.72 kV and 3.1 ms to 0.4 μs. When the ZnO volume fraction is higher than 30%, there is no residual voltage after 0.1 s. To explore the reason behind different electrostatic discharge performances of the ZnO/SiR composites, the conductivities of the composites were measured. It is found that the break-over voltage of the composite drops with the increase in the ZnO microvaristors volume fraction. When a high voltage impulse is applied on the ZnO/SiR film, the composite will turn to the conducting state and release the electrostatic charge adaptively so that the initial voltage can be controlled. This work supplies a novel electrostatic discharge idea for electric and electronic devices.