Inverse nonionic microemulsion studied by means of 1H, 13C, and PGSTE NMR during silica nanoparticle synthesis.

The soluble species present in the reaction mixture that leads to silica nanoparticle production through the base catalyzed hydrolysis of tetraethyl orthosilicate (TEOS) and the successive condensation were investigated in situ, under the actual synthesis conditions, by means of 1H, 13C, and 29Si NMR spectroscopy. The two former nuclei, owing to higher sensitivity and their presence both in the reacting species and in the constituents of the W/O microemulsion (cyclohexane-igepal-CA-520-concentrated ammonia solution) afforded insight into the inverse microemulsion and allowed us to assess the kinetic rate of the hydrolysis step. It was verified that the microemulsion microstructure is maintained during the reaction.

14N NMR spectra of molecular nitrogen in SDS/pentanol swollen lamellar phases.

14N NMR spectra of air dissolved in lyotropic mesophases are reported. In order to observe the whole spectrum from a molecule in which the quadrupole coupling constant is on the order of a few megahertz, a weak alignment degree with respect to the magnetic field is mandatory. Therefore, dilute lyotropic liquid crystals, namely sodium dodecylsulphate (SDS)/pentanol swollen lamellar phases, were considered.

Polymorphic behavior in protein-surfactant mixtures: the water-bovine serum albumin-sodium taurodeoxycholate system.

Mixtures containing water, bovine serum albumin (BSA), and sodium taurodeoxycholate (NaTDC), a component of the bile in mammals, have been investigated in a wide range of composition and pH. Depending on the concentration of both solutes and the pH, solutions, precipitates, and gels are formed. Under spontaneous pH conditions, the transport properties in dilute solutions indicate the occurrence of significant interactions between BSA and the surfactant.

NMR investigations of Co(III) coordination compounds oriented in a dilute lyotropic liquid crystal.

A swollen lamellar phase, based on sodium dodecyl sulfate, pentanol and NaBr brine, was examined by means of NMR spectroscopy of isotopes with quadrupolar characteristics, namely 2H, 17O, 23Na and 81Br, present at natural abundance. Such a dilute lyotropic liquid crystal was capable of inducing a preferential orientation of the cobalt coordination compounds [Co(en)3]3+ and Co(acac)3, the 59Co NMR signals of which displayed quadrupolar splittings. Moreover, it imparted alignment in the magnetic field to the organocobaloxime [ClCD2Co(Hdmg)2H2O], as shown by the quadrupolar splitting of the deuterium of the axial ligand.