In situ control of graphene oxide dispersions with a small impedance sensor

Abstract

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Piezoresistive Properties of Natural Hydraulic Lime Binary Pastes with Incorporated Carbon-Based Nanomaterials under Cyclic Compressive Loadings

“…The impedance spectra of the dispersions were interpreted via their respective Bode Plots. The respective Bode plots for all graphene-based nanostructures can be seen in [ 25 , 26 ], while similar approach was followed for the MWCNTs nanostructures. Figure 5 and Figure 6 display the Bode plots for the two different types of MWCNTs dispersion investigations and for four different concentrations per type.…”

“…The Bode plots show that an increase in ultrasonic energy leads to a reduction of impedance modulus |Z|. This behavior is different in comparison to graphene nanostructures, where an inversion is noted after a certain amount of ultrasonic energy [ 25 ]. This can be attributed to the structural differences among the nanostructures.…”

“…As noticed in relevant research articles, e.g., [ 25 , 26 ], graphene oxide dispersions exhibit lower impedance values, since it contains many different conductive functional groups. In contrast, rGO dispersions exhibit the highest impedance values in comparison with the other nanostructures.…”

“…Likewise, modification of MWCNTs improves their compatibility and stability, enhancing the potential of MWCNTs in sensing applications, e.g., [ 24 ]. For each nanostructure, aqueous dispersions were produced to find the optimal combination of ultrasonic energy and nano-reinforcement concentration (as wt.% of the binder), as described in previous works of the authors, e.g., [ 25 , 26 ]. The dispersion medium in the present investigation was bottled water (Epirotic Bottling Industry S.A.—VIKOS S.A.).…”

“…The evaluation of the aqueous dispersions was performed with a methodology developed in [ 25 ] that exploits Electrical Impedance Spectroscopy (EIS) measurements. EIS was performed during the ultrasonication process using a Dielectric Thermal Analysis System DETA-SCOPE ® (ADVISE, Chios, Greece).…”