Studies on an ester-modified cationic amphiphile in aqueous systems: Behavior of binary solutions and ternary mixtures with conventional surfactants

Lundberg, Dan,1975Chalmers tekniska högskola,Chalmers University of Technology (författare)

The aqueous behavior of an ester-modified cationic amphiphile with the molecular structure CH3CH2O(C=O)(CH2)(6)(C=O)O(CH2)sN+(CH3)(3)Br-, in the following referred to as A, has been investigated. Systems with A as the only solute, as well as different aqueous mixtures with conventional cationic surfactants, primarily dodecyltrimethylammonium bromide (DTAB), were included in the study. Isotropic solution samples were characterized using H-1 NMR, C-13 NMR, NMR diffusometry, and conductivity measurements, whereas liquid crystalline samples were investigated by optical polarization microscopy and small-angle X-ray diffraction. The results are compared to the behavior of the binary system of DTAB and water. A does not exhibit a typical surfactant behavior. When it is present as the only solute in a binary aqueous system, it forms neither conventional micelles nor liquid crystalline phases. However; there is clear evidence that it assembles with lower cooperativity into loose clusters at concentrations above 25-30 mM. When A is mixed with DTAB in solution, the two amphiphiles form mixed assemblies, the structure of which varies with the total amphiphile concentration. In concentrated mixtures with alkyltrimethylammonium surfactants, A can participate in hexagonal liquid crystalline phases even when it constitutes a significant fraction of the total amphiphile content.

Unga, Johan,1976Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)unga (författare)
Galloway, A. L. (författare)
Menger, F. M. (författare)
Chalmers tekniska högskola (creator_code:org_t)

Av författaren/redakt...: Lundberg, Dan, 1 ...; Unga, Johan, 197 ...; Galloway, A. L.; Menger, F. M.

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