Droplet Evaporative Crystallization on Regular Micro-structure Platform

Xiaobin Jiang, Mingguang Han, Gaohong He^*

School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China

E-mail: hgaohong@dlut.edu.cn

Abstract

Droplet evaporative crystallization on microscale heterogeneous surface is a vivid topic in chemical engineering, bioengineering, nanomaterials, etc. Here, an interfacial platform with regular pillar convexity and tunnel structure is fabricated to reveal the mechanism of the interfacial micro droplet crystallization. Element-based rotation volume model is established to simulate the concentration and nucleation barrier distribution during the microscale process. Sodium urate monohydrate and NaCl crystallization on the pillar convex structure both confirm that confined capillary flow in the micro droplet and initial nucleation condition dominate the nucleation, growth control and particle distribution. Droplet crystallization stretches over the tunnel structure reveal an interesting phenomenon that two regions possessing distinct-different nucleation barriers can isolated obtain the crystal particles from nanoscale to even millimetre scale. The fabricated platform and the capillary circulation transfer theory unfold a potential approach to develop novel micro-scale crystallization.

Figure 1 Nucleation energy barrier (J/mol) distribution (A-1 to A-4) and the corresponding crystal formation (B-1 to B-4) of SUM droplets with different initial saturated degree.