A Dipole-Confined Charge Transport Paradigm for Ultrahigh-Temperature Dielectric Polymers.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 42454561.
- Also identified by DOI 10.1002/adma.74073.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
A pervasive challenge in materials science, the incompatible trade-off among breakdown strength (E<sub>b</sub>), thermal stability (T<sub>g</sub>), and dielectric constant (ε<sub>r</sub>), has limited the development of polymer dielectrics for extreme-environment film capacitors. Here, this trilemma is overcome via a dipole-regulation strategy, confining polar methyl-sulfonyl groups within a rigid semi-aromatic polyimide framework using flexible methylene linkers. This dipole confinement domain structure of sulfonyl-methylene-benzene decouples dipolar response from charge transport: the flexible linkers enable polarization, while the rigid semi-aromatic framework localizes charges and suppresses conduction. It results in a stable dipole network, yielding a material (STPCB-PI) with a wide bandgap (4.38 eV) and a record T<sub>g</sub> (>400°C). It achieves a high ε<sub>r</sub> of 5.8, a modulus of 6.7 GPa, and exceptional energy storage, delivering 12.00 J cm<sup>-3</sup> with 97% efficiency at 25°C, 9.98 J cm<sup>-3</sup> with 94% efficiency at 150°C, and retaining 8.62 J cm<sup>-3</sup> with 90% efficiency at 200°C, 293% improvement over the state-of-the-art commercial polyetherimide. Even at 250°C, it maintains 4.24 J cm<sup>-3</sup> with 93% efficiency. It also exhibits excellent self-healing and cyclic endurance. This work sets a new performance benchmark and establishes a generalizable design paradigm that reconciles the intrinsic conflict between polarization and insulation in high-temperature dielectric polymers.