Characterization Of Graphene Oxide Nanofilms Obtained By The Saw Atomization

Due to its ability to absorb water molecules, graphene oxide (GO) is considered a promising material for sensitive coatings in fast surface acoustic wave (SAW) humidity sensors. In this work, we characterize GO films obtained by the SAW atomization technique. It is shown that the atomized submicroliter droplets of aqueous suspension of GO can be deposited onto the surface of Si, LiNbO3 or quartz substrates forming discrete or continuous films of nanometer thickness. The deposited films were examined using AFM and electron microscopy. We discuss the dependence of thickness and structure of the obtained GO films on the parameters of deposition: the number of atomized droplets, a volume of the initial droplet, a distance between the atomizer and the sample, etc. To evaluate the adsorption characteristics of the obtained GO films, we used them as sensitive coatings of the SAW humidity sensors. We found that the adsorption characteristics of the GO films are determined by fast adsorption on the surface of GO sheets and slow adsorption, attributed to limited penetration of water molecules between the sheets, and depend on the number of deposited layers.7

Characterization of graphene oxide nanofilms obtained by the saw atomization

Due to its ability to absorb water molecules, graphene oxide (GO) is considered a promising material for sensitive coatings in fast surface acoustic wave (SAW) humidity sensors. In this work, we characterize GO films obtained by the SAW atomization technique. It is shown that the atomized submicroliter droplets of aqueous suspension of GO can be deposited onto the surface of Si, LiNbO3 or quartz substrates forming discrete or continuous films of nanometer thickness. The deposited films were examined using AFM and electron microscopy. We discuss the dependence of thickness and structure of the obtained GO films on the parameters of deposition: the number of atomized droplets, a volume of the initial droplet, a distance between the atomizer and the sample, etc. To evaluate the adsorption characteristics of the obtained GO films, we used them as sensitive coatings of the SAW humidity sensors. We found that the adsorption characteristics of the GO films are determined by fast adsorption on the surface of GO sheets and slow adsorption, attributed to limited penetration of water molecules between the sheets, and depend on the number of deposited layers7

Influence of the deposition parameters of graphene oxide nanofilms on the kinetic characteristics of the SAW humidity sensor

Symmetric surface acoustic wave (SAW) atomizer was used to deposit graphene oxide (GO) nanofilms from microdroplets of the aqueous GO dispersion onto the surface of the SAW humidity sensors. The sensors with the deposited GO films were tested in a wide range of relative humidity and showed the amplitude of the response in the range of 1–40 kHz sufficient for the majority of applications. The kinetics of the adsorption of water molecules was modeled using the assumption that two independent first order adsorption processes take place. Saturation amplitudes and rate coefficients for both processes were experimentally evaluated using LSQ fitting of the sensor response in the time domain for the films obtained by different number of depositions. The mechanism of the adsorption of water molecules to the GO flakes is proposed and discussed2178891CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ590032/2011-