Micelles size/shape measurement

Most books related to analysis and characterization are divided into chapters on different techniques, such as Fluorescence or Self-diffusion NMR , i.e. the division is by method. By contrast, the division here is by problem. As an example, when the reader wants to find out how to best measure micelle size he (or she) does not need to know from the beginning which methods to consider. The reader can go directly to Chapter 38, Measuring Micelle Shape and Size, where the relevant information is collected. 

M. Nyd6n, Measuring micelle size and shape, in Handbook of Applied Surface and Colloid... 

To start with, NMR is a very powerful tool for the study of surface and colloid chemistry in general and several good reviews on this subject have been produced (1-5). As far as micelle size and shape are concerned, two main experiments prevail in the literature, namely NMR relaxation and self-diffusion measurements. The technique of NMR self-diffusion is a relative tool for the study of micellar size and shape since it uses the Stokes-Einstein relationship (or modifications to it) to... 

Information on micelle size and shape can be obtained from a variety of techniques such as light scattering, neutron scattering, viscosity measurements and osmotic pressures. Typically the micelles have a closely spherical shape in a rather wide concentration range above the CMC. Often there is no great change in shape until the surfactant solubility limit is reached, when a liquid-crystalline phase normally separates out. 

In Sections 8.3 and 8.4, we examine the structure of the different parts of a micelle and illustrate how the shape of the micelle is determined by the relative sizes of the head group and the tail of the surfactant. This relative measure provides a geometric rationale for the structures of aggregates that are possible, and is simple to use. 

Casein exists in milk as a calcium caseinate-calcium phosphate complex the ratio of these components is approximately 95.2 to 4.8. The dispersed casein particles appear to be spherical m shape and of various sizes. The size distribution of the casein micelles is nol constant, hut varies with aging, heating, concentration, and other processing treatments. Processing alters ihe water-binding of casein and this in turn affects the apparent viscosity of products that contain casein Changes in hydration have not been measured quantitatively although the casein panicles of raw milk... 

It appears that, through a combination of theoretical and experimental efforts, the kinetic methods have developed into one of the most fruitful approaches to the study of physico-chemical properties of micellar systems. One of the main problems that remains to be solved is the kinetics for systems containing rod-shaped micelles where the size distribution is very broad. There is also a problem in the interpretation of the amplitudes measured in the different kinetic experiments. 

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