香港理工大学王钻开团队研究了表面电荷如何影响液滴间的冻结。这一研究成果于2025年6月18日发表在《美国科学院院刊》杂志上。
表面液滴的冻结与航空、航海和运输等各种工业过程密切相关。先前的研究主要集中在物理化学不均匀但电均匀的表面上，液滴之间存在蒸汽压梯度是液滴间冻结桥接、传播和最终在整个表面结霜的主要机制。一个有趣但尚未解决的问题是，表面上的静电荷是否会影响冷冻动力学。研究组发现了电异质表面上的液滴间冷冻继电器（IFR）现象，该现象表现出三维的空气内冷冻传播路径和加速的冷冻速率。
理论和实验研究表明，这种现象源于冷冻液滴和相邻水滴之间建立的表面电荷梯度，这导致解冻的冰针从冷冻液滴中自发射出，然后触发相邻水滴以空气方式冻结。研究组进一步证明了它在各种介电基板、液体和液滴配置中的普遍性。该工作丰富了液滴冻结动力学的传统观点，并强调了静电在设计被动防冰和防霜材料中的关键作用。
附：英文原文
Title: How surface charges affect interdroplet freezing
Author: Yang, Siyan, Ji, Bingqiang, Feng, Yawei, Jin, Yuankai, Xu, Wanghuai, Lu, Jingyi, Qin, Xuezhi, Zhang, Huanhuan, Li, Mingyu, Xu, Zhenyu, Liu, Xiaonan, Xu, Luqing, Wang, Dehui, Wen, Rongfu, Wang, Zhenying, Wang, Steven, Ma, Xuehu, Wang, Zuankai
Issue&Volume: 2025-6-18
Abstract: The freezing of droplets on surfaces is closely relevant with various industrial processes such as aviation, navigation, and transportation. Previous studies mainly focus on physiochemically heterogeneous but electrically homogeneous surfaces, on which the presence of vapor pressure gradient between droplets is the predominant mechanism for interdroplet freezing bridging, propagation, and eventual frosting across the entire surface. An interesting yet unanswered question is whether electrostatic charge on surfaces affects freezing dynamics. Here, we find an interdroplet freezing relay (IFR) phenomenon on electrically heterogeneous surfaces that exhibits a three-dimensional, in-air freezing propagation pathway and an accelerated freezing rate. Theoretical and experimental investigations demonstrate that this phenomenon originates from the presence of surface charge gradient established between the frozen droplet and neighboring water droplet, which leads to a spontaneous shooting of desublimated ice needles from the frozen droplet and then triggers the freezing of neighboring water droplet in in-air manner. We further demonstrate its generality across various dielectric substrates, liquids, and droplet configurations. Our work enriches conventional perspectives on droplet freezing dynamics and emphasizes the pivotal role of electrostatics in designing passive anti-icing and antifrosting materials.
DOI: 10.1073/pnas.2507849122
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2507849122