Multilayer films of layered double hydroxide/polyaniline and their ammonia sensing behavior

•(ZnAl-LDH/PANI)n multilayer films have been fabricated via a layer-by-layer assembly way.•The multilayer films have relatively ordered morphology and controllable thickness.•The multilayer films show extremely high selectivity to ammonia at room temperature. This paper reports the fabrication of layered double hydroxide (LDH)/conductive polymer multilayer films by alternate assembly of exfoliated ZnAl-LDH nanosheets and polyaniline (PANI) on silicon wafer substrates using the layer-by-layer (LBL) deposition technology. UV–vis absorption spectroscopy indicates a stepwise and regular growth of the (LDH/PANI)n multilayer films upon increasing deposition cycles. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrate that the surfaces of the films are microscopy smooth and uniform with a thickness of 2nm per bilayer. Furthermore, the resulting (LDH/PANI)n multilayer films possess high selectively response to ammonia at room temperature. The presence of LDH nanosheets plays a critical role on the gas sensing for the pure PANI film has very low response to ammonia. The LBL assembly process based on LDH combines the conducting polymer and nano-inorganic material, which provides opportunities to develop new inorganic–organic films for gas sensing.