Microemulsions are known for their versatile properties widely utilized in fundamental research and industrial applications. They are thermodynamically stable mixtures structured on a colloidal length scale with an amphiphilic film separating water- and oil-rich domains. However, recent studies claim the existence of “surfactant-free microemulsions,” which exhibit structures on a molecular length scale. By means of systematic phase behavior and scattering experiments, this dissertation provides deep insights into the pathway from simple solutions to weakly and strongly structured microemulsions. With bulk-contrast SANS, the scattering behavior of a simple solution system made of water, cyclohexane, 1- and 2-propanol was found to be dominated by critical composition fluctuations (Ornstein-Zernike). Further analysis of critical phenomena revealed the critical exponent doubling that follows the scaling law γ ~ “2” ν. On the other hand, weak scattering signals described with a new model were detected in the film-contrast SANS data due to the nearby tricritical point (TCP). After crossing the TCP, the formation of well-defined amphiphilic films was demonstrated by increasing the amphiphilicity of the amphiphile. Subsequently, the influence of modifications of the amphiphilic film by adding novel diblock polymers was studied. As a result, enhanced efficiency and strengthened structural ordering were achieved in typical alkane microemulsions and novel CO2 microemulsions. Finally, the properties of industry-relevant microemulsions were investigated in two application-oriented projects. One project focused on the phase behavior and the microstructure of polyol-rich CO2 microemulsions, which can be used for the polyurethane (PU) foam production with cell sizes of a few micrometers. The other project focused on the formulation of optimum microemulsions stabilized by highly efficient extended surfactants. The experimental parameters from phase behavior studies helped determine the coefficients of the HLD equation, which can serve as a prediction tool for tackling a wide variety of formulation problems. Above all, this doctoral dissertation elucidated the pathway toward structured microemulsions and demonstrated versatile aspects of microemulsions’ applications.

During the last decade, various powerful experimental tools have been developed, such as small angle X-ray and neutron scattering, X-ray and neutron reflection from interfaces, neutron spin-echo spectroscopy and quasi-elastic multiple light scattering and large scale computer simulations. Due to the rapid progress brought about by these techniques, one witnesses a resurgence of interest in the physicochemical properties of colloids, surfactants and macromolecules in solution. Although these disciplines have a long history, they are at present rapidly transforming into a new, interdisciplinary research area generally known as complex liquids or soft condensed matter physics: names that reflect the considerable involvement of the chemical and condensed matter physicists. This book is based on lectures given at a NATO ASI held in the summer of 1991 and discusses these new developments, both in theory and experiment. It constitutes the most up-to-date and comprehensive summary of the entire field.

During the last decade there has been a renewed interest in research on supramolecular assemblies in solutions, such as micelles and microemulsions, not only because of their extensive applications in industries dealing with catalysts, detergency, biotechnology, and enhanced oil recovery, but also due to the development of new and more powerful experimental and theoretical tools for probing the microscopic behavior of these systems. Prominent among the array of the newly available experimental techniques are photon correlation spectroscopy, small-angle neutron and X-ray scattering, and neutron spin-echo and nuclear magnetic resonance spectroscopies. On the theoretical side, the traditionally emphasized thermodynamic approach to the study of the phase behavior of self-assembled systems in solutions is gradually being replaced by statistical mechanical studies of semi-micro scopic and microscopic models of the assemblies. Since the statistical mechanical approach demands as its starting point the microscopic struc tural information of the self-assembled system, the experimental determina tion of the structures of micelles and microemulsions becomes of paramount interest. In this regard the scattering techniques mentioned above have played an important role in recent years and will continue to do so in the future. In applying the scattering techniques to the supramolecular species in solution, one cannot often regard the solution to be ideal. This is because the inter-aggregate interaction is often long-ranged since it is coulombic in nature and the interparticle correlations are thus appreciable.

Demonstrating methods for overcoming stability issues in paints, wax dispersions, cosmetics, food products, and other industrial applications, this reference probes theoretical and practical issues surrounding microemulsion science and technology. Featuring the work of 51 international experts and containing almost 1000 instructive tables, equations, and illustrations, this book reviews the performance of, and prospects for, experimental methods such as X-ray diffraction, transmission electron microscopy (TEM), light scattering, small angle neutron scattering, viscosimetry, and nuclear magnetic resonance (NMR) to characterize various aspects of the dispersed phase of microemulsions.

This book gives an overview of the most recent advances in emulsion science, from the preparation to the destruction of these materials. This book is intended for a large audience, from undergraduate students to senior scientists. A progressive and didactic approach is proposed for that purpose. The concepts presented should provide a useful guidance for formulating and controlling the lifetime of emulsion at laboratory and industrial scales. For easy comprehension, the text is illustrated by more than 70 figures. This book is a new edition of the one published in the series "Springer Tracts in Modern Physics (vol. 181)". The main difference is a more didactic approach which will allow the non-specialist reader to capture the essential concepts. We shall also incorporate the very last research results (solid-stabilized emulsions, metastability) and novel applications (Biotechnology).

This book describes the microemulsion phenomenon in a systematic manner and not only provides an up-to-date introduction to this topic but aslo serves as the basis for further development in the area.The progress of microemulsion research has taken place in well-defined stages. The introduction period was founded on Schulman‘s original discovery and was, as expected, focused on the interfacial free energy. Because Schulman obtained his microemulsions from a macroemulsion by the addition of a cosurfactant.The present stage is characterized by an extensively enhanced knowledge about structure and dynamics in these systems. This has led to the realization that the structure of the microemulsions is related both to solutions with critical behaviour and long range order structures, the lyotropic liquid crystals. These two aspects have been elucidated independently by the French groups and by the Lund Spectroscopy group.