Self-assembly in a catanionic mixture with an aminoacid-derived surfactant: From mixed micelles to spontaneous vesicles

The aqueous self-assembly of a novel lysine-derived surfactant with a gemini-like architecture, designated here as 12-Lys-12, has been experimentally investigated for the amphiphile alone in water and in a mixture with dodecyltrimethylammonium bromide (DTAB). The neat surfactant forms interesting micrometer-sized rigid tubules in the dilute region, resulting in very viscous solutions. For the catanionic mixture with DTAB, various single and multiphase regions were identified (up to a total surfactant concentration of 1.5 wt %) by means of combined polarizing light microscopy, cryo-TEM, and NMR. In the DTAB-rich side, for a mixing molar ratio in the range 2 < DTAB/12-Lys-12 < 4, a region of stable, unilamellar vesicles can be found. Furthermore, it was found that upon addition of 12-Lys-12 to pure DTAB solutions, the mixed micelles grow and beyond a given mixing ratio, vesicles assemble and coexist with small micelles. The transition is not continuous, since there is a narrow mixing range where phase separation occurs. Self-diffusion measurements and cryo-TEM imaging show that the average vesicle radius is on the order of 30-40 nm.

Marques, Eduardo F. (author)
Gomes, Paula (author)
Falcao, Soraia (author)
Söderman, OlleLund University,Lunds universitet,Fysikalisk kemi,Enheten för fysikalisk och teoretisk kemi,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Physical Chemistry,Physical and theoretical chemistry,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH(Swepub:lu)fk1-oso (author)
Fysikalisk kemiEnheten för fysikalisk och teoretisk kemi (creator_code:org_t)

In:The Journal of Physical Chemistry Part B: American Chemical Society (ACS)110:37, s. 18158-181651520-52071520-6106

By the author/editor: Brito, Rodrigo O ...; Marques, Eduardo ...; Gomes, Paula; Falcao, Soraia; Söderman, Olle

About the subject

NATURAL SCIENCES: NATURAL SCIENCES; and Chemical Science ...; and Physical Chemist ...

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