[Frontiers in Bioscience S5, 611-630, January 1, 2013]

Changes in self-assemblies induced by temperature, concentration and light

Alfredo Gonzalez-Perez1, Margarita Sanchez-Dominguez2

1Membrane Biophysics Group, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen O / Denmark, 2Centro de Investigacion en Materiales Avanzados S.C. Unidad Monterrey; GENES- Group of Embedded Nanomaterials for Energy Scavenging, Parque PIIT, Alianza Norte 202 Apodaca, Nuevo Leon, Mexico, CP 66600

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Concentration and Temperature
3.1. Introduction to temperature and concentration aggregation changes
3.2. Sphere to rod transition: Concentration dependence
3.3. Effect of temperature on the cmc and micellar structure
3.4. Outlook
4. Ligth sensitive
4.1. Introduction to light-triggered aggregation changes
4.2. Photochemistry of photosurfactants
4.2.1. Cis-trans isomerizations: Stilbene
4.2.2. Cis-trans isomerizations: Azobenzene
4.2.3. Photoscission reactions
4.2.4. Polarity changes
4.2.5. Dimerizations
4.2.6. Photo-induced polymerization of surfactants
4.3. Examples of photo-induced aggregation changes
4.3.1. Vesicle transitions
4.3.2. Photo-induced aggregation changes involving viscosity changes: photo-rheological fluids.
4.3.3. Photo-induced aggregation changes involving liquid crystal phases
4.3.4. Miscellaneous light-induced aggregation changes
4.4. Outlook
5. References

1. ABSTRACT

In this review, changes in aggregation induced by thermodynamic parameters, namely concentration and temperature are discussed. Most of these changes are concerned with sphere-to-rod transitions. On the other hand, the use of an external trigger such as light can induce large aggregation changes in photosurfactant systems. This is discussed in the second part of this review and several examples of light-induced aggregation changes are included, demonstrating the usefulness of this approach.