Structure and transport properties of a charged spherical microemulsion system
Forskningsoutput: Tidskriftsbidrag › Artikel i vetenskaplig tidskrift
Abstract
Structure and transport properties of an oilinwater microemulsion of weakly charged spherical micelles were studied experimentally using viscosity, NMR selfdiffusion, and static and dynamic light scattering as well as theoretically by Brownian dynamics and Monte Carlo simulations and the PoissonBoltzmann equation. The micelles contain decane covered by the nonionic surfactant pentaethylene glycol dodecyl ether (C12E5) and the ionic surfactant sodium dodecyl sulfate. The system has a constant surfactanttooil ratio, and the total volume fraction of surfactant and oil, , is varied between 0.01 0.46. The micelles were made weakly charged by replacing a small fraction (0.01, 0.04, and 0.06) of the nonionic surfactant with ionic surfactant, retaining the micellar size. Comparison between selfdiffusion and viscosity coefficients measured as a function of concentration showed that the system obeys the generalized StokesEinstein relation at lower micellar concentrations. At higher micellar concentrations, a slightly modified equation can be used upon the addition of an extra frictional factor due to stronger interactions. The collective diffusion coefficient shows a maximum as a function of the volume fraction. This result is in good agreement with predictions based on a charged hardsphere model with hydrodynamic interactions. Other static and dynamic properties such as osmotic pressure, osmotic compressibility, and selfdiffusion coefficient were obtained theoretically from simulations based on a chargedsphere model. The static and dynamic properties of the charged hardsphere model qualitatively describe the behavior of the charged microemulsion micelles. At high volume fractions, > 0.1, the agreement is quantitative, but at < 0.1 the effect of the charge is smaller than what is predicted from the model.
Detaljer
Författare  

Enheter & grupper  
Forskningsområden  Ämnesklassifikation (UKÄ) – OBLIGATORISK

Originalspråk  engelska 

Sidor (fråntill)  10431053 
Tidskrift  Langmuir 
Volym  17 
Utgåva nummer  4 
Status  Published  2001 
Publikationskategori  Forskning 
Peer review utförd  Ja 