Synthesis of ionic ladderphane-derived triblock copolymer for dielectric and electrical energy storage applications

The ionic poly(bisnorbornenepyrrolidium) homopolymer ladderphane and the derived triblock copolymers containing two insulating polar blocks were synthesized by ring-opening metathesis polymerization. The homo-and copolymers displayed the dielectric constants of 21, 19, 18, and 17 accompanied with the dielectric losses of 0.14, 0.06, 0.04, and 0.03 at a frequency range of 100 Hz to 10 MHz, respectively. For copolymers, the ionic blocks were isolated between the insulating blocks and their conductivity values decreased obviously from 4.6×10^-6 to 7.2×10^-9 S cm^-1, resulting in a lower dielectric dissipation and higher charge-discharge efficiency than those of ionic homopolymer. This research presented a practical way to effectively improve the dielectric properties by combining the ionic, dipolar, and nano-interfacial polarizations, as well as the stereoregular microstructure of polymer chain.