Russev Stoyan C, Alexandrov Nikola, Marinova Krastanka G, Danov Krassimir D, Denkov Nikolai D, Lyutov Lyudmil, Vulchev Vassil, Bilke-Krause Christine
Department of Solid State Physics, Faculty of Physics, University of Sofia, Sofia 1164, Bulgaria.
Rev Sci Instrum. 2008 Oct;79(10):104102. doi: 10.1063/1.3000569.
We describe an instrument combining the advantages of two methods, axisymmetric drop shape analysis for well-deformed drops and capillary pressure tensiometry for spherical drops, both used for measuring the interfacial tension and interfacial rheological parameters. The rheological parameters are the complex interfacial elasticity, and the surface elasticity and viscosity of Kelvin-Voigt and Maxwell rheological models. The instrument is applicable for investigation of the effect of different types of surfactants (nonionic, ionic, proteins, and polymers) on the interfacial rheological properties both of air/water and oil/water interfaces, and of interfaces between liquids with equal mass densities. A piezodriven system and a specially designed interface unit, implemented in the instrument, ensure precise control for standard periodic waveforms of surface deformation (sine, square, triangle, and sawtooth) at a fixed frequency, or produce surface deformation at constant rate. The interface unit ensures accurate synchronization between the pressure measurement and the surface control, which is used for real-time data processing and feedback control of drop area in some of the applications.
我们描述了一种结合了两种方法优点的仪器，即用于形状良好液滴的轴对称滴形分析和用于球形液滴的毛细管压力张力测量法，这两种方法都用于测量界面张力和界面流变参数。流变参数包括复界面弹性以及开尔文 - 沃伊特和麦克斯韦流变模型的表面弹性和粘度。该仪器适用于研究不同类型的表面活性剂（非离子型、离子型、蛋白质和聚合物）对空气/水和油/水界面以及等质量密度液体之间界面的界面流变性质的影响。仪器中采用的压电驱动系统和专门设计的界面单元，可确保在固定频率下对表面变形的标准周期性波形（正弦波、方波、三角波和锯齿波）进行精确控制，或产生恒定速率的表面变形。界面单元确保压力测量与表面控制之间的精确同步，在某些应用中，这用于实时数据处理和液滴面积的反馈控制。
