Regensburg 2007 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 9: POSTER: Colloids and Nanoparticles

CPP 9.25: Poster

Montag, 26. März 2007, 16:00–18:00, Poster B

SAXS studies of choline carboxylate surfactants - soaps of physiological origin and outstanding solubility — •Regina Klein¹, Didier Touraud¹, Gerald Schneider², Tobias Pöpperl², and Werner Kunz¹ — ¹Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg — ²Institut für Physik, Universität Regensburg, 93040 Regensburg

Surfactants have been used for centuries in everyday life, e.g. for cleaning purposes or for the formulation of foods. The functionality of soaps derives from their amphiphilic molecular structure which is characterized by a polar head group providing water solubility, and a non-polar tail driving the formation of self-assembled aggregates in solution (micelles and liquid crystals). Common anionic soaps, such as alkali carboxylates, are restricted in their applicability due to their limited solubility in water. Important features such as the washing ability or the solubilising power can be improved by increasing the length of the hydrophobic chain. However, the longer the non-polar tail, the less soluble in water the corresponding surfactant is. A way to enhance the solubility of carboxylate surfactants in water and to ensure at the same time biocompatibility of the system is to replace the conventional alkali counter-ion by a quarternary ammonium ion of biological origin, such as choline ((2-Hydroxyethyl)trimethylammonium). Choline - formerly known as vitamin B4 - plays several key roles in the human body. In the present study, phase diagrams of choline carboxylates (C12-C18) have been established. Structural details such as the micellar shape and size were investigated by small-angle X-ray scattering.