Adipic Acid Primary Nucleation Kinetics from Probability Distributions in Droplet-Based Systems under Stagnant and Flow Conditions
Adipic Acid Primary Nucleation Kinetics from Probability Distributions in Droplet-Based Systems under Stagnant and Flow Conditions
复制标题
DOI：
10.1021/cg501836e
复制
发表时间：
2015-04-01
影响因子：
3.8
通讯作者：
Mazzei, Luca
中科院分区：
文献类型：
--
作者：
Rossi, Damiano;Gavriilidis, Asterios;Mazzei, Luca
在这项工作中，我们提出了一种微流体方法，允许在不同的流体动力学条件下进行成核研究。我们通过使用毛细管中的液/液分段流来确定己二酸溶液的初级成核速率和成核动力学参数，其中结晶介质被分配成小液滴。我们通过测量在静止（静止的液滴）和流动（移动的液滴）条件下单个液滴中晶体存在的概率作为时间、液滴体积和过饱和度的函数来实现这一点。将实验结果与经典成核理论模型和单核成核机制模型的预测进行比较，我们得出结论，己二酸在两种流体动力学条件下主要通过非均相机制成核。此外，我们表明，流动条件通过增加过程的动力学参数来提高初级成核率，而不影响热力学参数。在这方面，基于移动液滴内发生的内部再循环引起的成核附着频率的增强，讨论了可能的机制。
In this work, we present a microfluidic approach that allows performing nucleation studies under different fluid dynamic conditions. We determine primary nucleation rates and nucleation kinetic parameters for adipic acid solutions by using liquid/liquid segmented flow in capillary tubes in which the crystallizing medium is partitioned into small droplets. We do so by measuring the probability of crystal presence within individual droplets under stagnant (motionless droplets) and flow (moving droplets) conditions as a function of time, droplet volume, and supersaturation. Comparing the results of the experiments with the predictions of the classical nucleation theory model and of the mononuclear nucleation mechanism model, we conclude that adipic acid nucleates mainly via a heterogeneous mechanism under both fluid dynamic conditions. Furthermore, we show that the flow conditions enhance the primary nucleation rate by increasing the kinetic parameters of the process without affecting the thermodynamic parameters. In this regard, a possible mechanism is discussed on the basis of the enhancement of the attachment frequency of nucleation caused by the internal recirculation that occurs within moving droplets.