Wu Shuwang, He Zhiyuan, Zang Jinger, Jin Shenglin, Wang Zuowei, Wang Jianping, Yao Yefeng, Wang Jianjun
Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
School of Mathematical, Physical and Computational Sciences, University of Reading, Whiteknights, Reading RG6 6AX, UK.
Sci Adv. 2019 Apr 12;5(4):eaat9825. doi: 10.1126/sciadv.aat9825. eCollection 2019 Apr.
Establishing a direct correlation between interfacial water and heterogeneous ice nucleation (HIN) is essential for understanding the mechanism of ice nucleation. Here, we study the HIN efficiency on polyvinyl alcohol (PVA) surfaces with different densities of hydroxyl groups. We find that the HIN efficiency increases with the decreasing hydroxyl group density. By explicitly considering that interfacial water molecules of PVA films consist of "tightly bound water," "bound water," and "bulk-like water," we reveal that bulk-like water can be correlated directly to the HIN efficiency of surfaces. As the density of hydroxyl groups decreases, bulk-like water molecules can rearrange themselves with a reduced energy barrier into ice due to the diminishing constraint by the hydroxyl groups on the PVA surface. Our study not only provides a new strategy for experimentally controlling the HIN efficiency but also gives another perspective in understanding the mechanism of ice nucleation.
建立界面水与异质冰核形成（HIN）之间的直接关联对于理解冰核形成机制至关重要。在此，我们研究了具有不同羟基密度的聚乙烯醇（PVA）表面上的HIN效率。我们发现HIN效率随着羟基密度的降低而增加。通过明确考虑PVA薄膜的界面水分子由“紧密结合水”、“结合水”和“类本体水”组成，我们揭示了类本体水可直接与表面的HIN效率相关联。随着羟基密度的降低，由于PVA表面上羟基的约束减弱，类本体水分子能够以降低的能垒重新排列形成冰。我们的研究不仅为实验控制HIN效率提供了一种新策略，还为理解冰核形成机制提供了另一个视角。
