Zhang Xiaoqiang, Chen Hongyue, Wang Zhijun, Wang Nan, Zang Duyang
MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710129, China.
State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China.
Materials (Basel). 2023 Jul 22;16(14):5168. doi: 10.3390/ma16145168.
We studied the evaporation-driven crystallization in the droplets of sodium acetate anhydrous (CHCOONa) aqueous solution, which were deposited on superhydrophobic substrates. The results reveal distinct crystallization behaviors between saturated and unsaturated droplets under identical experimental conditions. Specifically, unsaturated droplets could form a quasi-spherical crystal shell on the superhydrophobic substrate, while saturated droplets could develop crystal legs between the droplet and substrate when the crystal shell formed. Subsequently, the saturated droplet was lifted off the substrate by the growing crystal legs. The formation of crystal shell was closely associated with the evaporation from the droplet surface and the internal convection inside the droplet. The formation of crystal legs was induced by the heterogeneous nucleation effect caused by the substrate of SiO nanoparticles. These findings provide valuable insights into regulating the morphology of salt crystallization through adjustments in salt solution concentration and substrate surface structure.
我们研究了沉积在超疏水基底上的无水醋酸钠（CH₃COONa）水溶液液滴中的蒸发驱动结晶过程。结果表明，在相同实验条件下，饱和液滴和不饱和液滴的结晶行为截然不同。具体而言，不饱和液滴可在超疏水基底上形成准球形晶体壳，而饱和液滴在形成晶体壳时，液滴与基底之间会生长出晶腿。随后，饱和液滴会被生长的晶腿从基底上抬起。晶体壳的形成与液滴表面的蒸发以及液滴内部的对流密切相关。晶腿的形成是由SiO₂纳米颗粒基底引起的异质成核效应所致。这些发现为通过调整盐溶液浓度和基底表面结构来调控盐结晶形态提供了有价值的见解。
