Impact of enhanced electric field on light-induced evaporation process of plasmonic nanofluid

Recently, some studies have shown that the vaporization of plasmonic nanofluids (PNFs) is observed to be more intensive than that of pure water during the light-induced heating process, but the mecha-nism remains controversial. In this work, we conduct several comparative experiments and molecular dynamics (MD) simulations to investigate the evaporation process of PNFs under the illumination of dif-ferent monochromatic incident lights, especially focusing on the plasma-mediated evaporation mecha-nism. Based on the experimental results of silver, gold, and graphite nanofluids, it is found that the evap-oration process of PNFs can be heavily promoted under the combined effect of the enhanced electric field induced by the localized surface plasmon resonance (LSPR) and the thermal diffusion. Combined with the electromagnetic theory, a modified MD simulation is developed to analyze the effect of the induced elec-tric field on the evaporation process of PNFs. The results indicate that nanoparticles with the LSPR effect are not only 'heat sources' which transfer the thermal energy to the surrounding media, but also can pro-duce the enhanced electric field to directly impact the motion of water molecules. The effect of localized electric field on the evaporation of PNFs cannot be neglected, especially during the initial evaporation pe-riod when the particle temperature is relatively low. The results also reveal that the light-induced evap-oration process of PNFs is quite different from the conventional thermo-mediated evaporation process in carbon-based nanofluids. Besides, some necessary conditions for exciting the plasma-mediated evapora-tion are also discussed. This work can offer some new insights for a comprehensive understanding of the evaporation process of PNFs, which is of fundamental interest to many emerging applications. (c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

This study investigates the evaporation process of plasmonic nanofluids (PNFs) through experiments and simulations. The results show that the combined effect of localized surface plasmon resonance (LSPR) and thermal diffusion can heavily promote the evaporation of PNFs. It is also found that the localized electric field has a significant impact on the evaporation process, especially in the initial stage when the particle temperature is low. This study provides new insights for understanding the evaporation process of PNFs comprehensively.