Reduced graphene oxide-polyethylene oxide composite films for humidity sensing via quartz crystal microbalance

A reduced graphene oxide (RGO)-Polyethylene Oxide (PEO) composite film was constructed on quartz crystal microbalance (QCM) with composite and bilayer film structures for ambient humidity detection. The morphology and chemical properties of the fabricated RGO-PEO composite materials were characterized by SEM, FTIR, Raman spectra and UV-vis spectroscopy respectively. The addition of RGO into PEO film contributes to a remarkable enhancement in dynamic response and sensitivity (20 Hz/%RH) compared with the pure PEO film (10 Hz/%RH). Furthermore, RGO-PEO composite film based sensor holds rapid response and recovery rates (11 s and 7 s at 84% RH @90% respectively), negative hysteresis (1.21%RH), stable repeatability and excellent long term stability. This research not only explore the feasibility of hygroscopic insulating polymer based composite in humidity detection but also provide an approach for advancement/optimization of QCM based humidity sensor. (C) 2017 Elsevier B.V. All rights reserved.