Supramolecular systems microemulsions

The main supramolecular self-assembled species involved in analytical chemistry are micelles (direct and reversed), microemulsions (oil/water and water/oil), liposomes, and vesicles, Langmuir-Blodgett films composed of diphilic surfactant molecules or ions. They can form in aqueous, nonaqueous liquid media and on the surface. The other species involved in supramolecular analytical chemistry are molecules-receptors such as calixarenes, cyclodextrins, cyclophanes, cyclopeptides, crown ethers etc. Furthermore, new supramolecular host-guest systems arise due to analytical reaction or process. 

D. Langevin In S.-H. Chen, J. S. Huang, and P. Tartaglia (eds), Low interfacial tensions in microemulsion systems. Structure and Dynamics of Strongly Interacting Colloids and Supramolecular Aggregates in Solution. 325. p. Kluwer, Dordrecht (1992). 

Names given to differentiate between supramolecular mono- and bilayer assemblies should be clear and relate to structure in a simple and general way. Micelle (Latin mic(a), grain -t- ella, diminutive suffix) indicates nothing but the ultimate smallness of these assemblies. The word microemulsion (Greek micro, small Latin emulsus, milked out) evokes a milk-like aqueous system containing (fat) droplets similar to those found in milk but much smaller. Both names produce, to a first approximation, an appropriate impression of the real systems. 

The book by Fuhrhop and Koning provides a new vista in this respect. It deals with micelle, microemulsion, monolayer and bilayer vesicle, micellar fibre, nanopore, amphiphilic crystal, and oligomolecular assembly. In spite of the much varied physicochemical characteristics of these molecular systems, common features which justify the synkinetic approach, as the authors advocate, emerge immediately. This unified understanding should enrich supramolecular chemistry. The skillful narrative of Fuhrhop, an accomplished chemist with the flair of a novelist, is apparent, as he has demonstrated in his previous book . The extensive use of computer graphics is an invaluable service to readers. I hope this book helps foster a new breed of chemists. 

Structural study of surfactant-based microheterogeneous liquid systems by the example of cetyltrimethylammonium bromide microemulsions under a tame scale alterations in the water-to-oil ratio. The advantages of this approach to study the structure of microcompartmentalized systems with different phase manifestations are shown. The obtained structural information is used to analyze the microenvironment of the reacting species and the kinetic data on the basic hydrolysis of carbon acids esters in the microemulsion reaction medium. Cohen et discussed diffusion NMR in supramolecular and combinatorial chemistry. Pregosin applied H, F, and pulsed field-gradient spin echo (PGSE) diffusion NMR spectroscopy in organometallic and catalytic chemistry. 

The first supramolecular self-reproduction experiments involved reverse micelles. Bachman et aL (22) have demonstrated that a reverse micellar system or water-in-oil microemulsion is endowed with the property of self-reproduction. The starting point is a microemulsion stabilized by octanol and octanoic acid. To this system, the fatty acid ester octyl octanoate was added. This is hydrolysed by LiOH to give the fatty acid and alcohol. As the reaction proceeds, more droplets of a similar structure/composition to those present initially are produced. This is because the reaction is localized within the boundary of the structure and so the reaction leads to the production of components of the boundary. 

In conclusion, ILs can act as guests to form supermolecules with several kinds of host molecules (i.e., cyclodextrins, cucurbit[n]urils and calixarenes), and can participate the constructing of supramolecular assemblies (i.e., micelles, microemulsions, lyotropic LCs, vesicles and gels). Besides, ILs can affect the formation of supramolecular structures, for example, the formation of polyrotaxanes and polypseudorotaxanes, the formation of the supramolecular structures in the extraction systems based on crown ethers, and so on It is... 

In addition, when ILs are used as solvents, how will the supramolecular structures of ILs themselves affect the formation of supramolecular assemblies. For example, when the surfactant is added into the IL/oil mixture, two cases would happen. If the hydrophobic interactions between oil and surfactant are stronger than the interactions between IL and oils, liquid clathrate can be destroyed and O/IL microemulsions form. Otherwise, a new state would exist instead of O/IL microemulsions. However, in the reference, this field has not been mentioned. Moreover, because trivial water is difficult to be removed and could be included in the supramolecular framework of imidazolium ILs, ILs are not pure, which makes the system more complicated. This supramolecular structure may also affect the formation of supramolecular assemblies. Recently, we noticed that water plays the key role in the formation of IL based microemulsions. A small quantity of water can lead to great change in the phase diagram of IL/TX-100/ oil ternary systems. Therefore, the effect of the supramolecular structures of ILs on the formation of supa-amolecular assemblies is another valuable subject. 

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