Interfacial superstructures

D. Lexa and J. M. Saveant, Supramolecular Effects in the Redox and Coordination Chemistry of Superstructured Iron Porphyrins, in Redox Chemistry and Interfacial Behaviour of Biological Molecules , eds.G. DryhurstandK. Niki, Plenum, New York, 1988, p. 1. 

Structural characterization of the support indicates that the lanthanum active component is the perovskite-type compound LaA103. The experimental results are interpreted as the formation of a three-fold superstructure of LaA103 which is in a good interfacial crystallographic fit with 5-AI2O3 and by the epitaxial relationship between the platinum and the support. 

A torsion pendulum apparatus was used to get information about the shear rheological properties of the surfactants at the interface. This sensitive instrument was not capable of detecting significant elastic or viscous properties except for Lecithine. The analysis provided data that indicated a low viscous resistance for Lecithine with an interfacial shear loss modulus of about 0.03 mN/m. Hence, we can conclude, that no network-like superstructures were formed, and that the large dilatational elastic response was mainly caused by Gibbs- and Marangoni-effects. 

In addition to counit concentration, the size of the branches also affects the degree of spherulite organization. It was observed that as the alkyl side chains become longer, they exert a greater influence on the interfacial structure of the crystallites. This in turn lowers the organization of the lamellar stacks and leads to less well-developed spherulitic superstructures [21]. 

---