Self-Assembly of Polyelectrolytic/Graphene Oxide Multilayer Thin Films on Quartz Crystal Microbalance for Humidity Detection

In this paper, poly (dimethyldiallylammonium chloride) (PDDA)/graphene oxide (GO) composite thin films with multilayer are layer-by-layer (LbL) assembled on quartz crystal microbalance (QCM) for humidity detection. The static and dynamic humidity sensing performances are successively studied using impedance analysis and oscillating circuit methods. The experiment results show that PDDA/GO composite thin films coated QCM humidity sensor exhibits large humidity sensing response, low humidity hysteresis, fast response and recovery, and excellent repeatability. In addition, the influence of the number of assembled layers of PDDA/GO on the performances of QCM humidity sensor has also been investigated. Meanwhile, the origin of the obtained excellent humidity sensing performances has been analyzed by considering the water adsorption/desorption mechanism of PDDA/GO composite multilayer thin films. This paper suggests that LbL self-assembly technique is a promising candidate method for fabricating high-performance QCM humidity sensor using PDDA/GO composite multilayer thin films as sensing material.