水基Ag@TiO_(2)纳米流体液滴光热蒸发特性研究

Investigation on Photothermal Evaporation Characteristics of Water-based Ag@TiO_(2) Nanofluid Droplets

开展等离激元纳米液滴在太阳辐照下的蒸发动力学行为研究对其在光热蒸发领域的应用具有重要意义。本文制备了在可见光波段吸光度与太阳光谱匹配良好的核壳结构Ag@TiO_(2)纳米颗粒;基于Tyndall效应和特征波长吸光度证明了不同浓度Ag@TiO_(2)纳米流体的稳定性;然后研究了太阳能照射下固着纳米流体液滴的接触角和体积变化,以获得其蒸发动力学信息。结果表明,尽管纳米颗粒浓度高达400μg/mL,但静置90 min后仍能保持95%以上;在太阳能加热过程中,纳米流体液滴经历了瞬态加热、缓慢加热和快速加热三个阶段;Ag@TiO_(2)纳米流体液滴以恒接触线模式蒸发,液滴体积随光照时间线性减小。

Studying the evaporation kinetics of plasmonic nanofluid droplets under solar irradiation is very important for their applications in photothermal evaporation areas.In this work,core-shell structured Ag@TiO_(2)nanoparticles with solar spectrum matching absorbance in the visible spectrum were synthesized.Moreover,the stability of Ag@TiO_(2)nanofluids with different concentrations was studied based on the Tyndall effect and characteristic wavelength absorbance.Subsequently,the nanofluids were employed to study the evaporation kinetics including contact angle and volume change of the sessile nanofluid droplet under solar irradiation.Results showed that although the particle concentration was as high as 400μg/mL,it remained above 95%after standing for 90 min.Moreover,the droplet underwent transient,slow,and rapid heating stages during solar heating.Furthermore,the Ag@TiO_(2)nanofluid droplet evaporated in a constant contact line mode,and the droplet volume decreased linearly with the illumination time.