Microstructure studies light microscopy

Polarized light microscopy is the study of the microstructures of objects using their interactions with polarized light [1,2,23-27,31-33]. The method is widely applicable to polymers [34] and to liquid crystals [34-37]. The polarizing micro-... 

If the microstructure is too fine, and the material is pleochroic, one can attempt to identify the azimuths for maximum and minimum absorption of linearly polarized light (171 in optically biaxial material, these need not coincide with the local extinction directions. The use of optical pleochroism as just described is one example of how studies limited to observations between crossed polars do not exhaust the information available from light microscopy. 

With the advent of confocal laser scanning fluorescence microscopy (CLSFM) [39], multiple photon microscopy (MPM) [40,41], and atomic force microscopy (AFM) [5], three new tools have been added to the standard tools of light microscopy (LM) [42-45] and electron microscopy (EM) [35,46-50] that were most widely used in the past to study the microstructure of fats and foods in general. The work of Heertje et al. [35,36,39,51] on visualization of the microstructure in fats remains one of the most important contributions to the field. In their method, a cold solvent mixture (butanol-methanol) was used to remove the liquid oil form the solid fat in a sample mounted on a special holder. After removal of the liquid oil, the structure of the solid fat network could be visualized. 

The apparatus used for IR microscopy is a Fourier-transform infrared (FTIR) spectrometer coupled on-line with an optical microscope. The microscope serves to observe the sample in white light at significant magnification for the purpose of determining its morphology, as well as to select the area for analysis. The spectrometer, on the other hand, enables study of the sample by transmission or reflection measurement for the purpose of determining the chemical composition. It also provides information about the microstructure and optical properties (orientation) of the sample. It is possible to apply polarised light both in the observation of the sample and in spectrometric measurements. 

The microstructure and particle morphology (size, shape, and surface roughness) of the colloids were studied with 13C and 29Si NMR spectroscopy, elemental analysis, transmission electron microscopy, and static and dynamic light scattering. 

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