Pan Ziqing, Trusler J P Martin, Jin Zhijun, Zhang Kaiqiang
Institute of Energy, Peking University, Beijing, P.R. China.
Ordos Research Institute of Energy, Peking University, Ordos, P.R. China.
Nat Protoc. 2025 Feb;20(2):363-386. doi: 10.1038/s41596-024-01049-0. Epub 2024 Sep 17.
The properties of the interface between materials have practical implications in various fields, encompassing capillary action, foam and emulsion stability, adhesion properties of materials and mass and heat transfer processes. Studying the dynamics of interfaces is also fundamental for understanding intermolecular interactions, change of molecular conformations and molecular aggregations. Pendant-drop tensiometry and its extension, the oscillating drop method, are simple, versatile methods used to measure surface tension, interfacial tension and interfacial rheological properties. These methods can, however, generate unreliable results because of inadequate material preparation, an incorrect calibration method, inappropriate selection of data for analysis, neglect of optical influences or operating the system outside the linear viscoelastic regime. In addition, many studies fail to report accurate uncertainties. This protocol addresses all these critical points and provides detailed descriptions of some operation tips relating to purifying methods for different kinds of material, the time frame for analyzing measurement data, the correction method for optical effects, implementation of the oscillating method with a common programmable pump and remedies for some common problems encountered during the measurement. Examples of interfacial tension measurements for two- and three-phase systems, as well as interfacial dilational modulus measurements for N and surfactant solutions, are provided to illustrate procedural details and results. A single measurement takes minutes to hours to complete, while the entire protocol, including the leak test, cleaning, repeated measurements and data analysis, may take several days.
材料之间界面的性质在各个领域都具有实际意义，包括毛细作用、泡沫和乳液稳定性、材料的粘附特性以及质量和热传递过程。研究界面动力学对于理解分子间相互作用、分子构象变化和分子聚集也至关重要。悬滴张力测量法及其扩展方法——振荡滴法，是用于测量表面张力、界面张力和界面流变特性的简单且通用的方法。然而，由于材料制备不充分、校准方法不正确、分析数据选择不当、忽视光学影响或在非线性粘弹性区域外操作该系统，这些方法可能会产生不可靠的结果。此外，许多研究未能报告准确的不确定度。本方案解决了所有这些关键点，并提供了一些操作提示的详细描述，这些提示涉及不同材料的纯化方法、测量数据分析的时间框架、光学效应的校正方法、使用普通可编程泵实施振荡法以及测量过程中遇到的一些常见问题的补救措施。提供了两相和三相系统界面张力测量的示例，以及N和表面活性剂溶液界面扩张模量测量的示例，以说明程序细节和结果。单次测量需要几分钟到几小时才能完成，而整个方案，包括泄漏测试、清洗、重复测量和数据分析，可能需要几天时间。
