论文标题
由新兴的热梯度和Marangoni流动驱动的液滴溶解
Droplet dissolution driven by emerging thermal gradients and Marangoni flow
论文作者
论文摘要
等温且纯粹弥漫性溶解在主机液体尺度上的寿命$τ$，其初始半径$ r_0 $ [langmuir，phys。 Rev. 12，368（1919）]。对于由于密度差异驱动的自然对流而导致的液滴溶解，其寿命尺度为$τ\ sim r_0^{5/4} $ [Dietrich等，J。Fluid Mech。 794，45（2016）]。在本文中，我们通过实验发现并从理论上得出了另一种液滴溶解行为，从而导致$τ\ sim r_0^4 $。当溶解动力学通过液体的局部加热控制时，会发生这种情况，从而导致修饰的溶解度和盘子周围的热量山脉流动。热梯度是通过将金纳米颗粒装饰的样品表面加热来实现的，在该表面上，浸入水饱和1-丁醇溶液中的无梗水滴坐着。所得的外壁热量流量和溶解度的温度依赖性决定了液滴溶解速率，从而导致液滴半径的收缩$ r（t）\ sim（τ-t）^{1/4} $，因此在$τ\ sim r_0^{4} $中。
The lifetime $τ$ of an isothermal and purely diffusively dissolving droplet in a host liquid scales as $τ\sim R_0^2$ with its initial radius $R_0$ [Langmuir, Phys. Rev. 12, 368 (1919)]. For a droplet dissolving due to natural convection driven by density differences, its lifetime scales as $τ\sim R_0^{5/4}$ [Dietrich et al., J. Fluid Mech. 794, 45 (2016)]. In this paper we experimentally find and theoretically derive yet another droplet dissolution behavior, resulting in $τ\sim R_0^4$. It occurs when the dissolution dynamics is controlled by local heating of the liquid, leading to a modified solubility and a thermal Marangoni flow around the droplet. The thermal gradient is achieved by plasmonic heating of a gold nanoparticle decorated sample surface, on which a sessile water droplet immersed in water-saturated 1-butanol solution is sitting. The resulting off-wall thermal Marangoni flow and the temperature dependence of the solubility determine the droplet dissolution rate, resulting in a shrinkage $R(t) \sim (τ-t )^{1/4}$ of the droplet radius and thus in $τ\sim R_0^{4}$.
