All-Organic Polymer Dielectrics Containing Sulfonyl Dipolar Groups and π–π Stacking Interaction in Side-Chain Architectures

Although polymer dielectrics show wide application prospects in electronic and electrical fields, a low relative dielectric constant and a low energy density restrict their rapid developments. To overcome these shortcomings, a strategy is proposed to facilitate orientational polarization through the incorporation of the π–π stacked biphenyl side groups in dipolar polymers. In this study, sulfonyl-containing poly(norbornene)s with and without biphenyl groups were synthesized by ring-opening metathesis polymerization, denoted as PBTMD-SO2 and PTMD-SO2, respectively. Their dielectric behaviors and energy-storage properties were investigated. The dielectric constant of PBTMD-SO2 with the biphenyl side groups was as high as 11.1 at 25 °C and 1 kHz, which was nearly 35% higher than that of PTMD-SO2 due to the stronger orientational polarization. In addition, the dielectric loss in the range of 1 kHz to 1 MHz increased from 0.061 to 0.172 for PTMD-SO2 and from 0.075 to 0.110 for PBTMD-SO2. Electric displacement–electric field loops studies indicated that the discharge energy density of PBTMD-SO2 reached 1.69 J/cm3 at 180 MV/m with a high efficiency of 87.1%, which exceeded the discharge energy density of 1.29 J/cm3 for PTMD-SO2 at 200 MV/m. This work offers a new idea for the design of high-performance dielectric polymers.