Dukhin A S, Goetz P J
Adv Colloid Interface Sci. 2001 Sep 3;92(1-3):73-132. doi: 10.1016/s0001-8686(00)00035-x.
We describe two different techniques (acoustics and electroacoustics), both of which employ ultrasound instead of light for extracting information about the properties of liquid-based dispersions. Ultrasound can propagate through samples that are not transparent for light, which open up many new applications not possible with classical light scattering methods. Acoustic and electroacoustic techniques offer a unique opportunity to characterize concentrated dispersion, emulsions and microemulsions in their natural states. Elimination of a dilution step required for most other techniques (light scattering, sedimentation, electrophoresis) is crucial for an adequate characterization of liquid dispersions, especially when the high concentration leads to structured systems. As with any macroscopic method, ultrasonic techniques characterize the sample in two steps. The first step is to measure some macroscopic property. The second step involves some theoretical treatment of the measured raw data which yields the desired information. Acoustic spectroscopy deals with measuring the attenuation of ultrasound within a certain frequency range. Electroacoustic spectroscopy has two implementations depending on the driving force. We emphasize here on the so-called Colloid Vibration Current (CVI) which is generated by the sound wave as it passes through the dispersion. A review of the theoretical basis of acoustics and electroacoustics is given, with emphasis on models that have been applied to concentrated systems. Recently, new theories have been developed for both acoustics and electroacoustics using a 'coupled phase model' and 'cell model concept'. The coupled phase model is widely used for describing a relative motion of the particles and liquid in the sound wave. The cell model approach opens the way to include both particle-particle interactions and polydispersity into the theoretical model. Experimental evidence is presented that shows that this new approach is successful in concentrated systems up to 45% vol. A short review of the possible applications of acoustics and electroacoustics measurements to a range of systems is presented including: ceramics, mixed dispersed systems, chemical-mechanical polishing abrasives, emulsions, microemulsions and latex materials.
我们描述了两种不同的技术（声学和电声学），这两种技术都使用超声波而非光来提取有关液基分散体性质的信息。超声波可以在对光不透明的样品中传播，这开启了许多传统光散射方法无法实现的新应用。声学和电声学技术为表征处于自然状态的浓缩分散体、乳液和微乳液提供了独特的机会。消除大多数其他技术（光散射、沉降、电泳）所需的稀释步骤对于充分表征液体分散体至关重要，尤其是当高浓度导致形成结构化体系时。与任何宏观方法一样，超声技术分两步对样品进行表征。第一步是测量一些宏观性质。第二步涉及对测量的原始数据进行一些理论处理，从而得出所需信息。声谱学涉及测量特定频率范围内超声波的衰减。电声谱学根据驱动力有两种实现方式。我们在此强调所谓的胶体振动电流（CVI），它是声波穿过分散体时产生的。本文给出了声学和电声学理论基础的综述，重点是已应用于浓缩体系的模型。最近，利用“耦合相模型”和“单元模型概念”为声学和电声学都开发了新理论。耦合相模型广泛用于描述声波中颗粒与液体的相对运动。单元模型方法为将颗粒间相互作用和多分散性纳入理论模型开辟了道路。给出的实验证据表明，这种新方法在高达45%体积分数的浓缩体系中是成功的。本文简要综述了声学和电声学测量在一系列体系中的可能应用，包括：陶瓷、混合分散体系、化学机械抛光磨料、乳液、微乳液和乳胶材料。
