Microemulsions in Cosmetics and Detergents

Abstract

Products for personal care and home care have to fulfil many different requirements regarding performance, aesthetics, costs and safety. This has consequences for the use of new technologies such as microemulsions for this kind of applications. If, for example, just one of these parameters (e.g. performance) is sufficient or even excellent while the other parameters do not meet the requirements, then the new technology will not be applied. This example reflects the challenges of applying microemulsions in cosmetic products and in detergency. Although there have been numerous basic studies with microemulsions which show superiority in certain aspects of performance, broad applications of microemulsions in detergency and cosmetic products are not yet achieved. The reasons for this are manifold and depend on the specific application. From an economical point of view the high surfactant concentration is one aspect. However, the fact that the formation of a microemulsion depends on various parameters such as the type of oil, the chosen surfactant, the temperature and the electrolyte content to mention just a few is even more important.As discussed in Chapters 1 and 3 of this book, the formation of microemulsions can be controlled by adjusting the temperature, the electrolyte content or the hydrophiliclipophilic balance by varying the ratio of different surface active agents. All these techniques are applicable in cosmetics and detergency and have specific advantages and disadvantages. For example, most consumer products require a temperature stability which is usually not achieved with temperature-induced microemulsions. Therefore, no general rule exists for the most suitable type of microemulsion but it depends on the application. In this chapter, several examples are given which describe the status of different applications in cosmetics and detergency. Microemulsions in cosmeticsMicroemulsions are used in many cosmetic products and are in the focus of current industrial and university research activities. The reasons and motivations are manifold. The following is a summary of their utilisation in several cosmetic product categories with many references to publications and patents. Common aspects of microemulsions Microemulsions: Background, New Concepts, Applications, Perspectives. Edited by Cosima Stubenrauch

Microemulsions with renewable feedstock oils

“…The presented results may be used to formulate more environmentally friendly industrial products, e.g. "green" cutting fluids, such as pesticides, 43 cosmetics 31,32 or pharmaceuticals. 41 Furthermore, from the phase diagrams shown in the present work (Fig.…”

“…29 Microemulsions have been intensively studied during the last few years by many scientists and technologists. The applications investigated at present range from classical fields like solubilization media in the food, cosmetic [30][31][32][33] and pharmaceutical industries, [34][35][36][37] oil recovery, 38 ground water remediation, 7,39 soil cleanup 40 and organic chemistry to new fields like improvement of fuels 5 or for use as decontamination media. 41 The use of microemulsions is not only advantageous due to the facile and low cost preparation, but also because of the improved bioavailability.…”

Using Microemulsions: Formulation Based on Knowledge of Their Mesostructure

“…It might be noted that, of course, there has been previous work summarizing industrial applications of microemulsions 14 and a general review is available on applications of microemulsions in cosmetics as well as in detergency, based on physical chemistry and thermodynamics of self-assembly, giving details on commonly used formulations. 460 A widespread use of microemulsions is as "template" for forming inorganic or organic nanoparticles. This is an enormously rich and interesting scientific field with abundant literature available.…”

“…It might be noted that, of course, there has been previous work summarizing industrial applications of microemulsions and a general review is available on applications of microemulsions in cosmetics as well as in detergency, based on physical chemistry and thermodynamics of self-assembly, giving details on commonly used formulations …”

Toward surfactant-free and water-free microemulsions

“…In every case, the surfactant and cosurfactant form always an interfacial film between the aqueous and oil phases. Microemulsions have been proven useful, particularly in the area of enhanced oil recovery [5] but also in the cosmetic [6][7][8], food [9,10], and pharmaceutical industries [11][12][13] or as cleaning agents [14,15].…”