http://www.bio21.bas.bg/ibf/PC_review.pdf

Phases and phase transitions of the phosphatidylcholines

The phase diagram of sodium dodecyl sulfate (SDS)-water system is established from differential calorimetric measurements. The SDS purification and the absence of degradation was checked using NMR analysis before and after the calorimetric recordings. Thermodynamic equilibrium of mixtures was achieved by using low heating rates (0.08°C/min). A quasi-continuous exploration of the phase diagram (0.2 wt% per step) with accurate temperature and enthalpy measurements allows precise determination of the complicated intermediate mesophase region. Six invariant reactions are identified. Temperatures of five of them are separated by small intervals (from 0.2 to 5°C). Tammann representations of enthalpies precisely determine the eutectoid and monotectoid compositions and invariant limits. In the surfactant-rich region, all the invariant limits appear at the same molar ratio: SDS/2 D2O, while the high hydration limits are located within a small composition range (from 57.1 to 66.4% SDS). Their enthalpies and entropies are discussed in relation to the mesophase structures and topology changes. The description of the surfactant-rich region is attempted. A dihydrate not previously reported is found. The freezing of water is also examined, and three types of water interactions are observed.

Phase diagram of sodium dodecyl sulfate-water system

Is vitrification involved in depression of the phase transition temperature in dry phospholipids

New insights into water-phospholipid model membrane interactions.

Lipid phase transitions measured in intact cells with fourier transform infrared spectroscopy

Successive phase-transition phenomena and phase diagram of the phosphatidylcholine-water system as revealed by differential scanning calorimetry

Thermal study of the interaction of crystalline surfactant with water; The dioctadecyldimethylammonium chloride-water system

Differential scanning calorimetry on the two-component system of dioctadecyldimethylammonium chloride (DOAC)–water was carried out in the temperature region from 80 °C down to -100 °C. As the result, a new type of glassy state was found around at -40 °C for the supercooled complete gel phase.

New Finding of the Glass Transition Phenomenon in Surfactant Gel Phase: The Binary System of Water and Dioctadecyldimethyl-Ammonium Chloride

Solid state proton magnetic resonance spectra were measured for the binary system of dioctadecyldimethylammonium chloride and water in different phases and at different compositions. From the lineshape and relaxation measurements it was shown that water in each phase consisted of multicomponents. In particular, the existence of intermediate water detected by thermal analyses was proved. NMR data also provided information on the dynamic behavior of water. The motion of the intermediate water in the gel phase was remarkable. By analysis of the split 1H NMR pattern due to dipole coupling and quadrupole splitting in the deuterium magnetic resonance spectra, an image of the motion of the intermediate water could be obtained.

Behavior of water molecules associated with the phase transitions in the binary system of dioctadecyldimethylammonium chloride and water studied by proton and deuterium magnetic resonances

Mika Kuwabara

Papers

Successive phase-transition phenomena and phase diagram of the phosphatidylcholine-water system as revealed by differential scanning calorimetry

Thermal study of the interaction of crystalline surfactant with water; The dioctadecyldimethylammonium chloride-water system

New Finding of the Glass Transition Phenomenon in Surfactant Gel Phase: The Binary System of Water and Dioctadecyldimethyl-Ammonium Chloride

Behavior of water molecules associated with the phase transitions in the binary system of dioctadecyldimethylammonium chloride and water studied by proton and deuterium magnetic resonances