Influence of surface processes on the dilational visco-elasticity of surfactant solutions.
Influence of surface processes on the dilational visco-elasticity of surfactant solutions.
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DOI：
10.1016/j.cis.2005.06.002
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发表时间：
2005-12
影响因子：
15.6
通讯作者：
F. Ravera;M. Ferrari;E. Santini;L. Liggieri
中科院分区：
文献类型：
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作者：
F. Ravera;M. Ferrari;E. Santini;L. Liggieri
液-液体系的力学性质，如动态界面张力和界面流变学，与所涉及的动力学过程和被吸附分子的行为密切相关。因此，只要建立了合适的模型和实验方法，研究这些性质就可以获得关于这些过程的定性和定量信息。本文介绍了液-液吸附层膨胀流变学的最新进展，包括有关表面活性剂在吸附层中发生转变的实验方法、模型和实验数据。模型既考虑了表面活性剂扩散引起的松弛，也考虑了吸附层内部的过程。特别是表面活性剂的重定向、聚集相变和界面化学反应被认为是可能的重组过程。这种方法允许将膨胀粘弹性作为摄动频率以及系统的平衡参数和动力学参数的函数来得到。结果也可以很容易地指定为不溶性单层。综述了毛细管压力张力计的主要实验技术，并详细讨论了毛细管压力张力计振荡式气泡/滴法的最新研究进展。介绍了两种具有重取向和聚集相变特征的表面活性剂的实验研究。除了提供对这些机制的更广泛的理解外，根据所开发的模型，对膨胀粘弹性数据的解释还允许有效地估计平衡和动力学参数。
The mechanical properties of liquid–fluid systems, like the dynamic interfacial tension and interfacial rheology are closely related to the kinetic processes involved and to the behaviour of the adsorbed molecules. Therefore, provided suitable models and experimental methods are set, investigating these properties allows qualitative and quantitative information on these processes to be drawn. This paper presents recent developments in dilational rheology of liquid–fluid adsorption layers, including experimental methods, models and experimental data concerned with surfactants undergoing transformations in the adsorption layer. Models account both for relaxation due to surfactant diffusion and to processes internal to the adsorption layer. In particular surfactant reorientation, aggregation phase transitions and interfacial chemical reactions have been considered as possible reorganisation processes. The presented approach, allows the dilational viscoelasticity to be derived as a function of the perturbation frequency and of the equilibrium and kinetic parameters of the system. The results can also be easily specified for insoluble monolayer. The principal experimental techniques are reviewed and the recent progresses in the implementation of an Oscillation Bubble/Drop method for Capillary Pressure Tensiometer are discussed in detail. Two experimental studies of surfactants characterised by re-orientation and aggregation phase transition are presented. Beside providing a wider comprehension of these mechanisms, the interpretation of the dilational visco-elasticity data, according to the developed models, allows the effective estimation of the equilibrium and kinetic parameters.