Estudo da taxa de geração de vapor em soluções coloidais contendo nanopartículas metálicas

Abstract

In this work, a study was performed on the photothermal properties of colloidal solutions, adding metallic nanoparticles in water. Gold and nickel oxide nanoparticles were used. The thermo-optical characteristics of the solvent, water, changes due to the presence of nanoparticles. On this scale, these effects are related to the surface plasmon resonance. To characterize these colloidal solutions, thermal diffusivity and optical absorption measurements were performed using the Thermal Lens technique and the Lambert-Beer Law, respectively. Finally, the water evaporation rate in the presence of metal nanoparticles was measured under the following conditions: different concentrations, different sizes, and different materials. We observe that there is an ideal concentration that provides us the highest evaporation rate. From it, the rate starts to decrease. This effect was attributed to the competition between light absorption and scattering in the samples. Thus, we demonstrate that adding gold to water increases its evaporation rate by a maximum of $50$\% while adding nickel oxide generates a maximum increase of $62$\%. This leads us to consider these solutions as potential candidates for technological applications such as cancer photothermal therapy and sterilization of medical equipment.