Zheng Lirong, Liu Zhuo, Zhang Qiang, Li Song, Huang Juan, Zhang Lei, Zan Bing, Tyagi Madhusudan, Cheng He, Zuo Taisen, Sakai Victoria García, Yamada Takeshi, Yang Chenxing, Tan Pan, Jiang Fan, Chen Hao, Zhuang Wei, Hong Liang
School of Physics and Astronomy, Institute of Natural Sciences, Shanghai National Center for Applied Mathematics (SJTU Center), MOE-LSC, Shanghai Jiao Tong University Shanghai 200240 China
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences Fuzhou Fujian 35000 China
Chem Sci. 2022 Mar 28;13(15):4341-4351. doi: 10.1039/d1sc04650k. eCollection 2022 Apr 13.
Interfacial water remains liquid and mobile much below 0 °C, imparting flexibility to the encapsulated materials to ensure their diverse functions at subzero temperatures. However, a united picture that can describe the dynamical differences of interfacial water on different materials and its role in imparting system-specific flexibility to distinct materials is lacking. By combining neutron spectroscopy and isotope labeling, we explored the dynamics of water and the underlying substrates independently below 0 °C across a broad range of materials. Surprisingly, while the function-related anharmonic dynamical onset in the materials exhibits diverse activation temperatures, the surface water presents a universal onset at a common temperature. Further analysis of the neutron experiment and simulation results revealed that the universal onset of water results from an intrinsic surface-independent relaxation: switching of hydrogen bonds between neighboring water molecules with a common energy barrier of ∼35 kJ mol.
界面水在远低于0°C的温度下仍保持液态且可移动，赋予被包裹材料柔韧性，以确保其在零下温度下具有多种功能。然而，目前缺乏一个统一的图景来描述不同材料上界面水的动力学差异及其在赋予不同材料特定系统柔韧性方面的作用。通过结合中子光谱和同位素标记，我们在0°C以下对多种材料独立研究了水和底层基质的动力学。令人惊讶的是，虽然材料中与功能相关的非谐动力学起始表现出不同的活化温度，但表面水在一个共同温度下呈现出普遍的起始。对中子实验和模拟结果的进一步分析表明，水的普遍起始源于一种与表面无关的固有弛豫：相邻水分子之间氢键的切换，其共同能垒约为35 kJ/mol。
