Interface design and dielectric response behavior of SiO2/PB composites with low dielectric constant and ultra-low dielectric loss

Abstract

The resistance-capacitance time delay, crosstalk interference and poor dimensional stability would damage the signal intact transmission. However, it was still a tough challenge to fabricate an interlayer dielectric material with low dielectric constant and low dielectric loss as well as excellent dimensional stability at the same time. In this work, for the first time, we constructed novel silicon dioxide/polybutadiene (SiO2/PB) composites with different SiO2 morphologies and surface function groups, which showed extremely low dielectric constant and dielectric loss in both low and high frequency bands. The crosslinking reaction between surface surficial vinyl groups of the SiO2 and PB macromolecules tremendously suppressed the interfacial polarization of the SiO2/PB composites. Therefore, the SiO2/PB composites exhibited low dielectric constant of 2.66 and ultralow dielectric loss of 0.0022 at high frequency band (10 GHz), and the coefficient of thermal expansion decreased to 154 × 10−6 /°C, which was three orders of magnitude less than that of the pure PB. The interface polarization response behavior of SiO2/PB composites was also elucidated by double layer theory, and the "resonance" phenomenon was firstly proposed to enhance the interface polarization. This work could provide a robust and simple strategy for the design of composites with ultralow dielectric loss and excellent dimensional stability for high-speed communication in different frequency bands.