- Title
- Propylammonium nitrate as a solvent for amphiphile self-assembly into micelles, lyotropic liquid crystals, and microemulsions
- Creator
- Atkin, Rob; Bobillier, Sophie M. C.; Warr, Gregory G.
- Relation
- Journal of Physical Chemistry B Vol. 114, Issue 3, p. 1350-1360
- Publisher Link
- http://dx.doi.org/10.1021/jp910649a
- Publisher
- American Chemical Society
- Resource Type
- journal article
- Date
- 2010
- Description
- The phase behavior and self-assembled microstructures of a range of oligo(oxyethylene)-n-alkyl ether (CiEj) surfactants has been investigated in propylammonium nitrate (PAN), a room temperature ionic liquid. Micelles and single-phase microemulsions were all found to form at alkyl chain lengths from dodecyl to octadecyl, and lyotropic liquid crystals formed with hexadecyl chains or longer. Small-angle neutron scattering (SANS) shows that self-assembly occurs by solvophobic interactions driving the aggregation of the alkyl chains, but several results indicate that these are weaker in PAN than in water or ethylammonium nitrate, due chiefly to the hydrophobicity of PAN. Longer alkyl chains are needed for lyotropic liquid crystals to form, and higher surfactant concentrations are needed to form a single phase microemulsion. Conductivity shows these microemulsions to be weakly structured, and relatively insensitive to oil or surfactant molecular structure, unlike water-based systems. However, SANS contrast variation reveals a nanosegregation of oil from the alkyl tails of surfactants within the microemulsion, and may suggest a cosurfactant-like role for the propylammonium cation. Molecular areas within microemulsions and lamellar phases are larger than corresponding water- or ethylammonium nitrate-based systems due to the large molecular volume of the solvating PANs.
- Subject
- propylammonium nitrate (PAN); lyotropic Liquid Crystals; microemulsions; small-angle neutron scattering (SANS)
- Identifier
- http://hdl.handle.net/1959.13/926836
- Identifier
- uon:9958
- Identifier
- ISSN:1520-6106
- Rights
- This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Physical Chemistry B, © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/jp910649a
- Language
- eng
- Full Text
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