Anisotropic aggregate

Compared to the colligative methods light scattering can yield information on a possible dissymmetry of the aggregates. For anisotropic particles the direction of the electric field associated with the incident light may not coincide with the shift of the electron cloud. The intensity of light scattered at (usually) 90° from anisotropic aggregates is increased over the value predicted on the basis of isotropy by the Cabannes factor. 

Fig. 29. Schematic representation of the anisotropic aggregation structure of 83 liquid crystal...

Spherulitic structure is common to many crystalline polymers. These spherulites are optically anisotropic aggregates of crystals arising from growth from a heterogeneous nucleus at their centre. In most cases, they grow until they fill the volume of the polymer and meet at planar surfaces so as to form polygonal structures (Fig. 37). The sizes of these spherulites... 

At high concentrations of the surfactant anisotropic aggregates are formed which may be considered as precursors to a liquid crystalline phase. 

Hendrikx Y, Charvofin J, Rawiso M, Liebert L, Holmes M (1983) Anisotropic aggregates of amphiphilic molecules in lyotropic nematic phases. J Phys Chem 87 3991-3999... 

Finally, protein-based fibrils can be formed and may be used to increase the stability of the interfacial film in spray-dried microcapsules. In concentrated protein solutions depending on the environmental conditions (pH, ionic strength, temperature) and the process conditions (e.g. shear), fibril structures or spherical aggregates may occur as a result of hydrolysis and denaturation [41,42]. In literature the formation of fibrils using p-lactoglobulin and whey protein isolate is described. These amyloid-like anisotropic aggregates are formed at pH values below the isoelectric point (pH 2.0. 0) and several hours of heating (at or above 80 °C)... 

A kinetic theory of fracture intends to interrelate the motion and response of molecules to the ultimate properties of a stressed sample. A kinetic theory, therefore, entails a molecular description of the deformation of the microscopically heterogeneous and anisotropic aggregates of chains to such an extent that critical deformation processes can be identified. The macroscopic deformation of any aggregate potentially involves the deformation, displacement, and/or reorientation of so different substructural elements as bond vectors, chain segments or crystal lamellae. 

When an external magnetic field is applied to an initially stable suspension of magnetic particles, a dipolar interaction arises that leads to the formation of anisotropic aggregates aligned along the field direction. The final morphology of the structures mainly depends on the particle volume fraction of the colloidal suspension ... 

These special properties are primarily the fact that oligomers are much more inclined to form more or less anisotropic aggregates than polymers with similar chemical structures. It is these anisotropic aggregates that allow us to declare macroscopic oligomer properties to be unique [11, 13, 15-20]. 

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