How ionic species structure influences phase structure and transitions from protic ionic liquids to liquid crystals to crystals.

The phase behaviour of n-alkylammonium (C6 to C16) nitrates and formates has been characterised using synchrotron small angle and wide angle X-ray scattering (SAXS/WAXS), differential scanning calorimetry (DSC), cross polarised optical microscopy (CPOM) and Fourier transform infrared spectroscopy (FTIR). The protic salts may exist as crystalline, liquid crystalline or ionic liquid materials depending on the alkyl chain length and temperature. n-Alkylammonium nitrates with n ≥ 6 form thermotropic liquid crystalline (LC) lamellar phases, whereas n ≥ 8 was required for the formate series to form this LC phase.

Protic ionic liquids (PILs) nanostructure and physicochemical properties: development of high-throughput methodology for PIL creation and property screens.

A high-throughput approach was developed in order to prepare and dry a series of protic ionic liquids (PILs) from 48 Brønsted acid-base combinations. Many combinations comprised an alkyl carboxylic acid paired with an alkyl amine. Visual screens were developed to identify which acid-base combinations formed PILs, and of those, which PILs were likely to have high surface tensions, low viscosities, and low melting points.

Lyotropic liquid crystal phases of phytantriol in a protic ionic liquid with fluorous anion.

The phase behaviour of phytantriol in the protic ionic liquid (PIL) 1-methylimidazolium pentadecafluorooctanoate (MImOF) and four different MImOF-water compositions was investigated by small- and wide-angle X-ray scattering (SAXS/WAXS), cross polarised optical microscopy (CPOM) and infrared spectroscopy (IR). MImOF is a distinct protic ionic liquid in that it contains a fluorocarbon anion and a hydrocarbon cation. This leads to MImOF having an unusual liquid nanostructure, such that it contains fluorocarbon, hydrocarbon and polar domains.

Protic ionic liquids with fluorous anions: physicochemical properties and self-assembly nanostructure.

A series of 11 new protic ionic liquids with fluorous anions (FPILs) have been identified and their self-assembled nanostructure, thermal phase transitions and physicochemical properties were investigated. To the best of our knowledge this is the first time that fluorocarbon domains have been reported in PILs. The FPILs were prepared from a range of hydrocarbon alkyl and heterocyclic amine cations in combination with the perfluorinated anions heptafluorobutyrate and pentadecafluorooctanoate.

Nanostructure and amphiphile self-assembly in polar molecular solvents: amides and the "solvophobic effect".

The ability of low molecular weight amides to support amphiphile self-assembly is shown to be a general feature for this class of solvents. This report extends the number of known polar solvents which can support amphiphile self-assembly by five new amides; more than doubling the number of known amides able to serve as amphiphile self-assembly media. The formation of lyotropic liquid crystalline phases by cationic and non-ionic surfactants in these liquid amides is reported.

Nanostructured protic ionic liquids retain nanoscale features in aqueous solution while precursor Brønsted acids and bases exhibit different behavior.

Small- and wide-angle X-ray scattering (SWAXS) has been used to investigate the effect that water has on the nanoscale structure of protic ionic liquids (PILs) along with their precursor Brønsted acids and bases. The series of PILs consisted of primary, secondary, and tertiary alkylammonium cations in conjunction with formate, nitrate, or glycolate anions. Significant differences were observed for these systems.

Monodisperse nonionic isoprenoid-type hexahydrofarnesyl ethylene oxide surfactants: high throughput lyotropic liquid crystalline phase determination.

The neat and lyotropic phase behavior of eight new ethylene oxide amphiphiles (EO = 1-8) with a hexahydrofarnesyl chain (3,7,11-trimethyldodecyl) and narrow polydispersity (>98.5% purity) is reported. Below five EO units the behavior of the neat surfactants show only a glass transition, Tg ∼ -90 °C.

Nanostructured nonionic thymidine nucleolipid self-assembly materials.

Three nucleoside lipids have been synthesized: 3'-oleoylthymidine, 3',5'-dioleoylthymidine, and 3'-phytanoylthymidine. Differential scanning calorimetry and X-ray diffraction have been employed to characterize the physical properties of these neat lipids. Polarizing optical microscopy, small-angle X-ray scattering, and cryo-transmission electron microscopy techniques have been used to investigate the phase behavior in aqueous systems.

Lanthanide phytanates: liquid-crystalline phase behavior, colloidal particle dispersions, and potential as medical imaging agents.

Lanthanide salts of phytanic acid, an isoprenoid-type amphiphile, have been synthesized and characterized. Elemental analysis and FTIR spectroscopy were used to confirm the formed product and showed that three phytanate anions are complexed with one lanthanide cation. The physicochemical properties of the lanthanide phytanates were investigated using DSC, XRD, SAXS, and cross-polarized optical microscopy.

Protic ionic liquids: physicochemical properties and behavior as amphiphile self-assembly solvents.

The physicochemical properties of 22 protic ionic liquids (PILs) and 6 protic molten salts, and the self-assembly behavior of 3 amphiphiles in the PILs, are reported. Structure-property relationships have been explored for the PILs, including the effect of increasing the substitution of ammonium cations and the presence of methoxy and hydroxyl moieties in the cation. Anion choices included the formate, pivalate, trifluoroacetate, nitrate, and hydrogen sulfate anions.

Formation of amphiphile self-assembly phases in protic ionic liquids.

A range of protic ionic liquids (PILs) have been identified as being capable of supporting the self-assembly of the nonionic surfactants myverol 18-99 K (predominantly monoolein) and phytantriol. PIL-surfactant penetration scans have provided a high throughput technique to determine which lyotropic liquid crystalline phases were formed in the 40 PIL-surfactant systems investigated. Lamellar, inverse hexagonal, and bicontinuous cubic phases that are stable in excess PIL have been observed in surfactant-PIL systems.

Many protic ionic liquids mediate hydrocarbon-solvent interactions and promote amphiphile self-assembly.

A large number of protic ionic liquids (PILs) have been found to mediate solvent-hydrocarbon interactions and promote amphiphile self-assembly. Hexagonal, cubic, and lamellar lyotropic liquid crystalline phases were observed in PIL-hexadecyltrimethylammonium bromide systems. The driving force for the formation of the self-assembled aggregate structures has been attributed to an entropic contribution to the free energy of association, analogous to the hydrophobic effect in water.

Protic ionic liquids: solvents with tunable phase behavior and physicochemical properties.

The phase behavior, including glass, devitrification, solid crystal melting, and liquid boiling transitions, and physicochemical properties, including density, refractive index, viscosity, conductivity, and air-liquid surface tension, of a series of 25 protic ionic liquids and protic fused salts are presented along with structure-property comparisons. The protic fused salts were mostly liquid at room temperature, and many exhibited a glass transition occurring at low temperatures between -114 and -44 degrees C, and high fragility, with many having low viscosities, down to as low as 17 mPa.s at 25 degrees C, and ionic conductivities up to 43.