Biocompatible lecithin organogels: structure and phase equilibria.
The microstructure of organogels formed upon the addition of tiny amounts of water to a solution of lecithin in fatty acid esters (viz. isopropylpalmitate and ethyloleate) was investigated by means of molecular self-diffusion measurements. In both systems lecithin and water form disconnected cylindrical reverse micelles. The ternary phase map for the lecithin/water/isopropylpalmitate has been investigated in detail. The organogel exists in a narrow region close to the lecithin-oil binary axis; for higher water content equilibrium between lamellae and reverse micelles is found. Lamellar phase occupies the lecithin-rich region, close to the lecithin corner (with the exception of a small island of hexagonal phase) and coexists with neat water close to the water-lecithin axis. The remaining part of the phase map shows the three-phase coexistence of water, oil, and lamellar phase.
Angelico
Ruggero
R
DISTAAM, Università del Molise, v. De Sanctis, I-861 00 Campobasso, Italy.
Ceglie
Andrea
A
Colafemmina
Giuseppe
G
Lopez
Francesco
F
Murgia
Sergio
S
Olsson
Ulf
U
Palazzo
Gerardo
G
D001672:Biocompatible Materials; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010168:Palmitates; D010713:Phosphatidylcholines / Q000737:chemistry*; D012212:Rheology; D014867:Water
D001672:Biocompatible Materials; D010168:Palmitates; D010713:Phosphatidylcholines; D014867:Water; C005060:isopropyl palmitate