Enhancing Effect of Halloysite Nanotubes on Sensitivity and Stability of Hybridized Acrylate Copolymer Humidity-sensitive Films
Polymer materials have been extensively utilized in the fabrication of humidity-sensitive materials;however,certain issues such as inadequate sensitivity,sluggish response speed,and insufficient desorption capability still hinder their developmental potential.This study aims to enhance the humidity sensitivity of impedance-type humidity sensors by incorporating polyacrylic resin(HAC)with halloysite nanotubes(HNTs).Scanning electron microscopy,transmission electron microscopy and atomic force microscopy were used to observe the surface topographic features and roughness of the material films,which demonstrated that the doping of HNTs improved the humidity-sensitive performance of the composite.The molecular structure of the materials was tested by infrared spectroscopy,which proved the successful doping of HNTs to form the composites.The thermogravimetric curve of the material was tested using a thermogravimetric analyzer,which showed that the material had good thermal stability.The impedance of the fork finger electrode was tested using an LCR digital bridge,and the results showed that the moisture-sensitive response curve of the material had a high linearity(r=0.99986),ultra-fast response/recovery speed(0.4 s/9.8 s),small wet hysteresis(0.78%RH),and a low temperature coefficient of variation(0.013%RH/℃).The humidity response mechanism of the materials was investigated using complex impedance spectroscopy,which was dominated by the intrinsic conductivity of the humidity-sensitive materials in the low and medium humidity ranges,and by the ionic conductivity in the high humidity range.
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