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Magnetic and Phase Behavior of Magnetic Water‐in‐Oil Microemulsions
Author(s) -
Brown Paul,
Mohamed Azmi,
Ardyani Tretya,
Rogers Sarah E.,
Eastoe Julian
Publication year - 2017
Publication title -
journal of surfactants and detergents
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.349
H-Index - 48
eISSN - 1558-9293
pISSN - 1097-3958
DOI - 10.1007/s11743-017-1961-9
Subject(s) - pulmonary surfactant , microemulsion , chemistry , small angle neutron scattering , phase (matter) , analytical chemistry (journal) , bromide , neutron scattering , chromatography , chemical engineering , scattering , inorganic chemistry , organic chemistry , optics , engineering , biochemistry , physics
Magnetic water‐in‐oil microemulsions with anisotropic morphology have been generated by mixing single‐chain magnetic surfactants (dodecyltrimethylammonium trichloromonobromoferrate, DTAF) with non‐magnetic di‐chain analogues (didodecyldimethylammonium bromide, DDAB). Full phase diagrams have been mapped as a function of surfactant composition, water content, and temperature. It was shown that for all surfactant concentrations [Surfactant total ], on replacing 30 wt% DDAB with DTAF optimum (i.e. wt% of the total surfactant) w ratios ( w = [water]/[surfactant]) could be achieved; up to w = 120 for [Surfactant total ] = 0.050 M. Small‐angle neutron scattering (SANS) indicated that microemulsion droplets have a rod‐like morphology with a radius commensurate with the surfactant tail length and an aspect ratio between 6 and 35. In the presence of a large magnetic field (6.7 T) no reorientation of the droplets was observed by SANS.