dc.contributor.author | Kotlarchyk, Michael | en_US |
dc.contributor.author | Sheu, Eric | en_US |
dc.contributor.author | Capel, Malcolm | en_US |
dc.date.accessioned | 2006-12-18T18:01:04Z | en_US |
dc.date.available | 2006-12-18T18:01:04Z | en_US |
dc.date.issued | 1992-07-15 | en_US |
dc.identifier.citation | Physical Review A 46N2 (1992) 928-923 | en_US |
dc.identifier.issn | 1050-2947 | en_US |
dc.identifier.uri | http://hdl.handle.net/1850/3148 | en_US |
dc.description | RIT community members may access full-text via RIT Libraries licensed databases: http://library.rit.edu/databases/ | |
dc.description.abstract | A small-angle x-ray scattering (SAXS) study of dense AOT-water-decane microemulsions [AOT denotes sodium bis(2-ethylhexyl) sulfosuccinate] was undertaken in order to delineate clearly the phase behavior and corresponding structural transitions for AOT-plus-water volume fractions ranging from φ=0.60 to 0.95. Spectra were collected for temperatures between T=3 and 65 °C. The resulting T-vs-φ phase diagram indicates three distinct structural domains when the water-to-AOT molar ratio is fixed at W=40.8, namely, the previously investigated L2 droplet phase, a high-temperature Lα lamellar phase, and a low-temperature L3 phase consisting of randomly connected lamellar sheets. A significantly wide coexistence region accompanies the droplet-to-lamellar phase transition, which is demonstrated to be first order. For W between 15 and 40, an analysis of the lamellar structure using a one-dimensional paracrystal model produces a Hosemann g factor indicative of an approximately constant variation in the lamellar spacing of about 8%. The SAXS study was supplemented by dielectric-relaxation, shear-viscosity, and quasielastic light-scattering measurements in order to substantiate the observed phase transitions and further our understanding of the structural and dynamical properties of the L3 phase. It was found that the L3 phase exhibits Newtonian behavior up to a shear rate of 790 s-1, in contradiction to previous theoretical considerations. The phase exhibits two distinct relaxation modes. A relaxation time of ~1 ms characterizes the Brownian motion of a single lamellar sheet, while the motion of the entire interconnected sheet assembly has a relaxation time on the order of 1 s (Refer to PDF file for exact formulas). | en_US |
dc.description.sponsorship | Acknowledgment is made to the Donors of the Petroleum Research Fund, administered by the American Chemical Society, for the partial support of this research (Grant No. 21202-GB7). The SAXS experiments performed at Oak Ridge National Laboratory were partially supported by the Division of Materials Sciences, U.S. Depatrment of Energy under Contract No. DE-AC05-84OR21400 with Martin Marietta Energy Systems, Incorporated. SAXS experiments were also performed at the National Synchrotron Light Source, Station X12B, which is owned and operated by the Biology Department of the Brookhaven National Laboratory under funding from the Office of Health and Environmental Research, FWP KP04-01 and KP04-BO43. We are grateful to J.S. Lin of ORNL for assistance with the 10-m small-angle scattering spectrometer. Special thanks are given to Rheometrics Inc. for granting us instrumentation time, and to R. Shar for providing indispensable assistance with the viscosity measurements. R. Strey provided helpful discussions regarding the microemulsion phase diagram. Sample preparation and tireless technical assistance were provided by M.M. DeTar. | en_US |
dc.format.extent | 1768961 bytes | en_US |
dc.format.mimetype | application/pdf | en_US |
dc.language.iso | en_US | en_US |
dc.publisher | American Physical Society | en_US |
dc.relation.ispartofseries | vol. 46 | en_US |
dc.relation.ispartofseries | no. 2 | en_US |
dc.subject | Anionic surfactant | en_US |
dc.subject | Dielectric relaxation | en_US |
dc.subject | Electrical properties | en_US |
dc.subject | Hydrocarbon | en_US |
dc.subject | Lamellar structure | en_US |
dc.subject | Light scattering | en_US |
dc.subject | Microemulsion | en_US |
dc.subject | Quasi electric scattering | en_US |
dc.subject | Small angle X-ray scattering | en_US |
dc.subject | Transport properties | en_US |
dc.title | Structural and dynamical transformations between neighboring dense microemulsion phases | en_US |
dc.type | Article | en_US |
dc.identifier.url | http://dx.doi.org/10.1103/PhysRevA.46.928 | |