Experimental design and response surface methodology applied to the dielectric properties of hydroalcoholic solutions containing sodium chloride

Abstract The main focus of this study was to use an experimental design to and the response surface statistical technique to predict and optimize the dielectric properties of hydrated ethanol-sodium chloride blends. Several samples of these blends were prepared considering the following variables: hydrated ethyl alcohol concentration, sodium chloride concentration and temperature. The main dielectric properties of these blends, i.e., the dielectric constant, dielectric loss factor and dissipation factor, were measured in a calibrated device suitable for liquid or pasty substances. For this study, experimental tests were carried out according to a Central Composite Design (CCD). Response surface techniques were used to predict the magnitude of the effect of the input variables on the responses investigated, particularly on the dissipation factor. This factor represents the ability of the substance to convert electromagnetic energy into heat. Within the experimental range studied here, the values of the variables that optimized the response were as follows: sodium chloride concentration of 2.21%, hydrated ethanol concentration of 4.64% and temperature of 87 °C.