Insulating polyimide films containing n‐type perylenediimide moieties

Oxadiazole‐containing polyperyleneimides were prepared by high‐temperature solution polycondensation reaction of an aromatic diamino‐oxadiazole with a mixture of two dianhydrides, one containing a perylene moiety and the other containing a hexafluoroisopropylidene unit. Flexible films having good mechanical properties were made therefrom. The structure of the polymer films was confirmed using X‐ray photoelectron spectroscopy. Some polymer films were subjected to measurements of electrical insulating properties. The variation of the real and imaginary parts of the dielectric permittivity with frequency and temperature was recorded. The values of the dielectric constant, dielectric loss and specific resistance were obtained at 25 °C and in the frequency domain from 1 Hz to 130 kHz. The dielectric spectroscopy data showed distinct γ and β subglass transitions for these polymers at low activation energies. Electronic conduction through a hopping mechanism in these polyimide films was determined from AC conductivity measurements. Copyright © 2012 Society of Chemical Industry