Polyzwitterionic Material Structure and Dielectric Properties

There is a growing need for flexible, high-dielectric-constant materials that move beyond current polar solvent swelling and nanofiller approaches to advance energy storage and actuator applications. Here, we synthesized a series of statistical copolymers consisting of polybutyl acrylate-co-poly(2-(dimethylamino)ethyl acrylate), which were then converted into polyzwitterions to explore the impact of zwitterions on the material structure and dielectric properties. The DMAEA residues in each copolymer were quaternized using 1,4-butane sultone to yield polyzwitterions through postpolymerization modification. The functionalization of the copolymers with zwitterions increases the static dielectric constant of the materials (i.e., ∼9.3 at 80 °C) compared with the unquaternized materials. The strong dipolar interactions between zwitterions lead to aggregation, resulting in the appearance of either a second glass-transition temperature or the softening of the zwitterion aggregates. Although the zwitterions increased the dielectric constant of the materials, the zwitterion-rich aggregates are posited to restrict zwitterion mobility, precluding the maximum material dielectric constant. The reported findings position polyzwitterions as promising next-generation dielectric materials, potentially broadening applications in flexible electronics and energy-efficient devices.