Polyaniline-intercalated layered double hydroxides: synthesis and properties for humidity sensing

Abstract

A series of polyaniline and sodium dodecanesulfonate co-intercalated layered double hydroxides (LDH/PANI/SDS) have been obtained by a coprecipitation method. The composites have been named LiAl-LDH/PANI/SDS, MgAl-LDH/PANI/SDS, and NiAl-LDH/PANI/SDS according to the composition of the LDH nanosheets. The structure and chemical composition of the composites have been characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetry and differential thermal analysis. It has been observed that SDS serves as both the interlayer anion and the template for the formation of LDH sheets, which induces the co-intercalation of PANI. All the composites have been incorporated into humidity sensors and humidity sensing experiments have been conducted. It has been found that the humidity sensors based on LDH/PANI/SDS demonstrate good humidity properties with good linearity, low hysteresis, good stability and rapid response compared with PANI alone. The sensing mechanism of the composites has also been discussed.