Structural insights into the cubic–hexagonal phase transition kinetics of monoolein modulated by sucrose solutions

摘要: Using DSC (differential scanning calorimetry), we measure the kinetics of cubic–HII phase transition monoolein in bulk sucrose solutions. We find that temperature is dramatically lowered, with each 1 mol kg−1 concentration dropping by 20 °C. The this also slow greatly increasing concentration. For low concentrations, are asymmetric, cooling (HII–cubic) taking twice as long heating (cubic–HII) transition. This asymmetry times reduced for higher concentrations. exhibits Avrami exponents range 2 to 2.5 and shows ranging from 3. A classical interpretation would be these processes occur via a one or two dimensional pathway variable nucleation rates. non-classical perspective suggest reflect time dependence pore formation (cooling) destruction (heating). New density measurements show currently accepted value about 5% too low; has substantial implications electron modeling. Structural calculations indicate head group area lipid length shrink 12% 4% respectively; reduction practically same seen very different molecular structure (rac-di-12:0 β-GlcDAG) makes Thermodynamic considerations there hydration shell water molecule thick front groups both cubic HII phases.