6533b852fe1ef96bd12aabac
RESEARCH PRODUCT
Small angle neutron scattering studies of critical phenomena in a three-component microemulsion
Hideki SetoShigehiro KomuraRoberto TrioloGeorge D. WignallD. Chillura-martinosubject
Phase boundaryCrystallographyUpper critical solution temperatureChemistryCritical phenomenaThermodynamicsMicroemulsionSmall-angle scatteringStructure factorLower critical solution temperatureSmall-angle neutron scatteringdescription
Critical density fluctuations of a ``water-in-oil`` microemulsion consisting of water, benzene, and BHDC (benzyldimethyl-n-hexadecyl ammonium chloride) were observed near the phase boundary by SANS. Observed profiles were well described by product of a form factor of spherical droplets and a structure factor, consisting of a term describing the inter-droplet correlations and also an Ornstein- Zernike component describing the droplet density fluctuations. Allowance was also made fro droplet polydispersity,though the width of the distribution turned out to be very small (1-2%). Observed temperature dependence of osmotic compressibility was fitted using the crossover function proposed by Belyakov et al., and the Ginzburg numbers were obtained on the order of 10{sup -2}. This indicates that long range interdroplet forces are not significant in this system, which displays upper critical solution temperature behavior. In contrast, previous studies of systems displaying lower critical solution temperature behavior (e.g., water, n-decane, and dioctyl sulfosuccinate sodium salt) indicate that long range interactions appear to dominate the phase separation behavior.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2007-10-03 |