Study of the In Situ Postintercalative Polymerization of Metanilic Anions Intercalated in NiAl‐Layered Double Hydroxides under a Nitrogen Atmosphere

Abstract

AbstractA new route has been developed for preparing polyaniline (PANI) layered double hydroxide (LDH) nanocomposites through in situ chemical oxidative polymerization of metanilic anions (m‐NH2C6H4SO3–) intercalated in NiAl LDHs under a nitrogen atmosphere by using pre‐intercalated nitrate as an oxidizing agent. The interlayer space of NiAl LDHs has been used as an original nanoreactor for the in situ polymerization of the intercalated monomer. The whole process involves the synthesis of the precursor LDH [Ni2Al (OH)6(NO3)·nH2O], the intercalation of the monomer metanilic anions into the LDH and its in situ polymerization between the layers by thermal treatment under a nitrogen atmosphere. The interlayer polymerization reaction was monitored by thermogravimetric analysis (TG), differential thermal analysis (DTA), mass spectrometry (MS), UV/Vis absorption spectroscopy, in situ X‐ray absorption near edge structure (XANES) spectroscopy, in situ high‐temperature X‐ray diffraction (HT‐XRD) and in situ Fourier transform infrared (FTIR) spectroscopy. The UV/Vis spectra provide evidence for the polymerization of the intercalated metanilic anions, and an increase in the interlayer distance from 16.0 to 17.2 Å is observed by HT‐XRD. It has been found by the in situ techniques that the pre‐intercalated nitrate anions act as the oxidizing agent that induces the polymerization of the interlayer monomer under a nitrogen atmosphere upon heating at 300 °C. The orientation of the interlayer polymerization product has also been proposed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)