Fluorinated compounds, including alkanes, alkenes, aromatics, amines, and cyclic and heterocyclic fluorochemicals, are studied as solvents of oxygen, using for this purpose the paramagnetic relaxation induced by the presence of molecular oxygen onto the I3C nuclei of neighboring solvent molecules in the solution. Relaxation data are expressed by the variation rates qx of relaxation rates TI-' per mole fraction of dissolved oxygen. A general correlation is found between the solubility of oxygen (in mole fraction) and the relaxation coefficients qx, the lower qx values being associated to the higher solubilities. This was accounted for by the existence of large cavities in the liquid for the better solvents, which can thus accommodate small gaseous molecules more easily, while simultaneously the magnetic dipolar interaction between oxygen and solvent nuclei is decreased. The sequence found for compounds of decreasing solubility, aliphatic > cyclic > aromatic, can be rationalized on the basis of cavities of decreasing size from one class of solvents to the other. The order of solubility seems to depend mainly upon the shape of solvent molecules and not upon the details of molecular structure, thus discarding the alternative assumption of specific fluorine-oxygen forces and of a possible charge-transfer complex. The higher relaxation coefficients obtained for some typical analogous hydrocarbons can be rationalized by using the same concepts.

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Hybrid materials consisting of a monoolein lipidic cubic phase (LCP) incorporating two types of magnetic nanoparticles (NP) were designed as addressable drug delivery systems. The materials, prepared in the form of a gel, were subsequently used as a macroscopic layer modifying an electrode and, after dispersion to nanoscale, as magnetocubosomes. These two LCPs were characterized by small-angle X-ray scattering (SAXS), cross-polarized microscopy, magnetic measurements, and phase diagrams. The magnetic dopants were hydrophobic NP and hydrophilic NP, characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM), and their influence on the properties of the cubic phases was investigated. The removal of the anticancer drug, Doxorubicin (Dox) from the hybrid cubic phase gels was studied by electrochemical methods. The advantages of incorporating magnetic nanoparticles into the self-assembled lipid liquid crystalline phases include the ability to address the cubic phase nanoparticle containing large amounts of drug and to control the kinetics of the drug release.