β-Cyclodextrin toughened polyimide composites toward all-organic dielectric materials.

Flexible all-organic dielectric materials are highly required for miscellaneous applications in modern flexible electronics and energy storage devices but are often hindered by the poor mechanical performance, especially the poor toughness. In this work, because of the special chemical structures and properties, β-cyclodextrin (β-CD) was used to toughen the polyimide (PI) matrix and improve the dielectric properties. Dynamic mechanical analysis (DMA) indicated that β-CD was miscible with PI matrix. The obtained PI/β-CD composite films exhibited a high dielectric permittivity of 8.11, breakdown strength of 217 MV/m, maximum energy density of 1.46 J/cm, tensile strength > 160 MPa, toughness > 56 J/g, T > 300 °C and T > 280 °C, which are much better than other all-organic dielectric materials, such as PVDF and its derivatives. These PI/β-CD composite films would be promising materials for all-organic film capacitors. [ABSTRACT FROM AUTHOR]