哥伦比亚大学闵玮小组报道了油-水界面微观结构与超强电场。该研究于2025年3月19日发表于国际一流学术期刊《自然》杂志上。

在这里，课题组报告了一种溶液中，界面选择性拉曼光谱方法，主题是多元曲线分辨率，以探测水中十六烷乳液，并借助于拉曼光谱的单体场理论模型。他们的结果表明，油水乳液界面可以表现出四面体秩序的降低和较弱的氢键，以及大量的自由羟基，大约有95与平面油水界面相比，其拉伸方式红移。鉴于已知油滴的静电zeta电位特性，该团队提出存在一个从油相发出的强电场（约50–90 MV cm⁻¹）。这个领域是间接推断出来的，但有控制实验和理论估计的支持。在由小溶质形成的分子疏水界面或平面油水界面中，这些观察结果要么不存在，要么相反。相反，水结构紊乱和增强的电场是油水乳液中尺度界面的独特特征，可能有助于在疏水界面上观察到的加速化学反应。

据了解，界面水表现出丰富而复杂的行为，在化学、生物、地质和工程等领域发挥着重要作用。然而，关于疏水界面上的水的基本性质，如取向顺序、水合氢离子和氢氧根的浓度、不适当的氢键和大电场的存在，仍然存在许多争论。即使使用最先进的实验技术和理论方法，这种争议也源于测量界面系统的挑战。

附：英文原文

Title: Water structure and electric fields at the interface of oil droplets

Author: Shi, Lixue, LaCour, R. Allen, Qian, Naixin, Heindel, Joseph P., Lang, Xiaoqi, Zhao, Ruoqi, Head-Gordon, Teresa, Min, Wei

Issue&Volume: 2025-03-19

Abstract: Interfacial water exhibits rich and complex behaviour1, playing an important part in chemistry, biology, geology and engineering. However, there is still much debate on the fundamental properties of water at hydrophobic interfaces, such as orientational ordering, the concentration of hydronium and hydroxide, improper hydrogen bonds and the presence of large electric fields2,3,4,5. This controversy arises from the challenges in measuring interfacial systems, even with the most advanced experimental techniques and theoretical approaches available. Here we report on an in-solution, interface-selective Raman spectroscopy method using multivariate curve resolution6,7 to probe hexadecane-in-water emulsions, aided by a monomer-field theoretical model for Raman spectroscopy8. Our results indicate that oil–water emulsion interfaces can exhibit reduced tetrahedral order and weaker hydrogen bonding, along with a substantial population of free hydroxyl groups that experience about 95cm1 redshift in their stretching mode compared with planar oil–water interfaces. Given the known electrostatic zeta potential characteristic of oil droplets9, we propose the existence of a strong electric field (about 50–90MVcm1) emanating from the oil phase. This field is inferred indirectly but supported by control experiments and theoretical estimates. These observations are either absent or opposite in the molecular hydrophobic interface formed by small solutes or at planar oil–water interfaces. Instead, water structural disorder and enhanced electric fields emerge as unique features of the mesoscale interface in oil–water emulsions, potentially contributing to the accelerated chemical reactivity observed at hydrophobic–water interfaces10,11,12,13.

DOI: 10.1038/s41586-025-08702-y

Source: https://www.nature.com/articles/s41586-025-08702-y