Spontaneous Vesicle Formation in a Deep Eutectic Solvent

Solvent penetration experiments and small-angle X-ray scattering reveal that phospholipids dissolved in a deep eutectic solvent (DES) spontaneously self-assemble into vesicles above the lipid chain melting temperature. This means DESs are one of the few nonaqueous solvents that mediate amphiphile self-assembly, joining a select set of H-bonding molecular solvents and ionic liquids.Australian Research Counci

Effect of Protic Ionic Liquid Nanostructure on Phospholipid Vesicle Formation

The formation of bilayer-based lyotropic liquid crystals and vesicle dispersions by phospholipids in a range of protic ionic liquids has been investigated by polarizing optical microscopy using isothermal penetration scans, differential scanning calorimetry, and small angle X-ray and neutron scattering. The stability and structure of both lamellar phases and vesicle dispersions is found to depend primarily on the underlying amphiphilic nanostructure of the ionic liquid itself. This finding has significant implica-tions for the use of ionic liquids in soft and biological materials and for biopreservation, and demon-strates how vesicle structure and properties can be controlled through selection of cation and anion. For a given ionic liquid, systematic trends in bilayer thickness, chain-melting temperature and enthalpy in-crease with phospholipid acyl chain length, paralleling behaviour in aqueous systems.Australian Research Council, ANSTO, AINS

Phase Behavior of Amphiphilic Diblock Co-oligomers with Nonionic and Ionic Hydrophilic Groups

The synthesis of a series of co-oligomer amphiphiles by RAFT and their self-assembly behavior in water is described. These novel amphiphiles, comprised of styrene, butyl acrylate, and alkyl hydrophobes together with ionic acrylic acid and nonionic hydroxyethylacrylate hydrophilic moieties and with a total degree of polymerization from 5 to 17, represent a new class of small-molecule surfactants that can be formed from the immense potential library of all polymerizable monomers. Examples of micellar solutions and discrete cubic, hexagonal, lamellar, and inverted hexagonal lyotropic phases, as well as vesicle dispersions and coexisting lamellar phases, are reported and characterized by small-angle scattering. The variation of self-assembly structure with co-oligomer composition, concentration, and solution conditions is interpreted by analogy with the surfactant packing parameter used for conventional small-molecule amphiphil