Controlled synthesis and humidity sensing properties of CdS/polyaniline composite based on CdAl layered double hydroxide

- The CdS/polyaniline composite with sandwich structure was prepared.
- The CdS nanoparticles were prepared by sulfuration of layered double hydroxide.
- CdS/PANI composite shows excellent humidity properties with fast response-recovery time.

CdS/polyaniline (CdS/PANI) composite with sandwich structure has been prepared by vulcanization process of polyaniline and sodium dodecyl sulfonate (SDS) co-intercalated CdAl layered double hydroxide (CdAl-LDH/PANI), which has been obtained by traditional method of hydrothermal synthesis. CdAl-LDH/PANI precursor and CdS/PANI composite have been characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). The preparation process applies the framework of layered double hydroxide to prepare CdS nanoparticles and combines the intercalation of PANI to fabricate the sandwich structure of CdS/PANI composite. A humidity sensor based on the CdS/PANI composite has been further fabricated and tested. It indicates that the CdS/PANI composite with the sandwich structure shows excellent humidity properties with a good linearity between the logarithmic resistance and the relative humidity above 35% RH, fast response-recovery time and good repeatability compared with the pure PANI and CdS and the simple mixture of PANI and CdS.

CdS/polyaniline (CdS/PANI) composite with sandwich structure has been prepared by in-situ vulcanization process of polyaniline and Sodium dodecyl sulfonate co-intercalated (SDS) CdAl layered double hydroxides (CdAl-LDH/PANI), which has been obtained by traditional method of hydrothermal synthesis. The preparation process applies the framework of layered double hydroxide to prepare CdS nanoparticles and combined the intercalation of PANI to fabricate the sandwich structure of CdS/PANI composite. The CdS/PANI composite with the sandwich structure shows excellent humidity properties with a good linearity, fast response-recovery time and good repeatability compared with the pure PANI and CdS and the simple mixture of PANI and CdS. The sandwich structure provides polymer molecules with a confined and stable environment, which improves humidity and thermal stability.132