Molecular Layer Deposition of Thermally Stable Polybenzimidazole‐Like Thin Films and Nanostructures

Abstract The deposition of polybenzimidazole (PBI)‐like thin films by molecular layer deposition is reported here for the first time using isophthalic acid (IPA) and 3,3′‐diaminobenzidine (DAB) as monomers and trimethylaluminum (TMA) as a linker precursor. Two precursor pulsing sequences are tested, the ABCB (TMA + IPA + DAB + IPA) and ABC (TMA + IPA + DAB) type MLD processes result in different types of PBI‐like films. With the ABCB sequence thin film growth per cycle (GPC) of 6.0 Å is obtained at 225–280 °C, whereas GPC of 7.0 Å is obtained with the ABC sequence. Films are characterized in detail by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, time‐of‐flight elastic recoil detection analysis, and atomic force microscopy. The films have good thermal stability and withstand annealing at 400 °C in both air and nitrogen. PBI nanostructures are prepared by depositing PBI‐like film on electroblown polyvinylpyrrolidone fibers and removing the template fibers by annealing or dissolution into ethanol.