Publication

Characterization of monomeric and gemini cationic amphiphilic molecules by fluorescence intensity and anisotropy

Kuppuswamy Kalyanasundaram, Guido Viscardi
2009
Journal Articles

Abstract

Pyrene fluorescence intensity and conductivity measurements were used to determine the cmc of two monomeric surfactants namely, dodecyltrimethylammonium bromide and cetyltrimethylammonium bromide as well as two gemini surfactants, 16-3-16 2Br and 16-4-16 2Br of the alkanediyl-alpha,omega-bis(alkyldimethyl ammonium bromide) type. Cmc measurements were confirmed using fluorescence anisotropy measurements employing fluorescein as probe. Anisotropy-concentration plots showed sigmoidal behaviour and the obtained values for cmc were in good agreement with those determined using conductivity and pyrene fluorescence intensity. Also, the anisotropy of both fluorescein and another fluorescent probe. perylene, were used to provide information on the micellar structure. (C) 2008 Elsevier Ltd. All rights reserved.

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https://infoscience.epfl.ch/entities/publication/3bb78b55-426c-444f-a497-511b9c881244

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Kuppuswamy Kalyanasundaram, Guido Viscardi
2009
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/3bb78b55-426c-444f-a497-511b9c881244

About this result

Related concepts (9)

Surfactant

Surfactants are chemical compounds that decrease the surface tension or interfacial tension between two liquids, a liquid and a gas, or a liquid and a solid. Surfactants may function as emulsifiers, wetting agents, detergents, foaming agents, or dispersants. The word "surfactant" is a blend of surface-active agent, coined 1950. Surfactants are usually organic compounds that are akin to amphiphilic, which means that this molecule, being as double-agent, each contains a hydrophilic "water-seeking" group (the head), and a hydrophobic "water-avoiding" group (the tail).

Critical micelle concentration

In colloidal and surface chemistry, the critical micelle concentration (CMC) is defined as the concentration of surfactants above which micelles form and all additional surfactants added to the system will form micelles. The CMC is an important characteristic of a surfactant. Before reaching the CMC, the surface tension changes strongly with the concentration of the surfactant. After reaching the CMC, the surface tension remains relatively constant or changes with a lower slope.

Micelle

A micelle (maɪˈsɛl) or micella (maɪˈsɛlə) (plural micelles or micellae, respectively) is an aggregate (or supramolecular assembly) of surfactant amphipathic lipid molecules dispersed in a liquid, forming a colloidal suspension (also known as associated colloidal system). A typical micelle in water forms an aggregate with the hydrophilic "head" regions in contact with surrounding solvent, sequestering the hydrophobic single-tail regions in the micelle centre. This phase is caused by the packing behavior of single-tail lipids in a bilayer.

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