CPL - Chalmers Publication Library
| Utbildning | Forskning | Styrkeområden | Om Chalmers | In English In English Ej inloggad.

Diffusion of water in multilamellar vesicles of dialkyl and dialkyl ester ammonium surfactants

Cecilia Groth (Institutionen för material- och ytkemi, Teknisk ytkemi) ; Johanna Bender (Institutionen för material- och ytkemi, Teknisk ytkemi) ; Magnus Nydén (Institutionen för material- och ytkemi, Teknisk ytkemi)
Colloids and Surfaces A: Physicochemical and Engineering Aspects (0927-7757). Vol. 228 (2003), 1-3, p. 64-73 .
[Artikel, refereegranskad vetenskaplig]

The NMR self-diffusion technique is used for measuring diffusion of water in highly concentrated multilamellar vesicle solutions. The signal intensity of water, i.e. the water echo-decay, is monitored down to very small intensities thus providing an accurate measure of how water is diffusing in the solution. It is noted that a large curvature is dominating the functional form of the echo-decay indicating the presence of a large number of multilamellar vesicles. It is also concluded that in order to measure accurately the volume fraction of water inside and outside vesicles the experimental time scale can be changed. From a multiexponential fit to the echo-decay the fraction fast and the sum of all slow components can be extracted. When the apparent fraction "vesicle water", P-vw(app), is plotted versus the experimental time scale the graph produced is a good representation of the difference in how fast water diffuses over the different vesicle membranes. From an extrapolation to "zero time" the true fraction of trapped water can be extracted, i.e. a quantitative measure of the volume fraction of vesicles at a certain concentration of surfactant.

Nyckelord: Geeneral Phase-Behavior, SDS-DDAB-Water, Rich Side, Permeation, Permeability, Molecules, Bilayers, Field



Denna post skapades 2006-08-25. Senast ändrad 2011-02-17.
CPL Pubid: 12968

 

Läs direkt!


Länk till annan sajt (kan kräva inloggning)


Institutioner (Chalmers)

Institutionen för material- och ytkemi, Teknisk ytkemi (2002-2004)

Ämnesområden

Kemi

Chalmers infrastruktur

Relaterade publikationer

Denna publikation ingår i:


Diffusion in cationic vesicle and micellar solutions- a NMR study


A physico-chemical investigation of cationic surfactants in solution