Shaping potentialities of aluminum nitride polymeric precursors: Preparation of thin coatings and 1D nanostructures in liquid phase

The present paper is focused on the synthesis of a series of poly[N-(alkylimino)alanes] of the type [HAlNR]_n as preceramic polymers for the preparation of aluminum nitride (AlN). Polymers were characterized by means of Fourier transform infrared spectra (FT-IR), liquid-state ¹H and ¹³C NMR spectrometry and elemental analyses. The polymers were prepared in different physical states going from viscous liquid to solid (soluble and/or fusible) compounds with the decrease of the carbon content in the polymer chain. Such properties offer potentialities in the preparation of complex forms of ceramics including thin coatings and 1D nanostructures. AlN thin coatings and 1D nanostructures were obtained from a solution of poly[N-(isopropylimino)alane] in toluene followed by heat-treatment in flowing ammonia up to 1000 °C resulting in a ceramic yield of 50.6%. Subsequent heat-treatment to 1800 °C in flowing nitrogen allowed the production of crystalline AlN coatings and nanorods identified by Raman spectrometry and X-ray diffraction.