LYOTROPIC LIQUID-CRYSTAL PHASE-BEHAVIOR OF THE ZWITTERIONIC SURFACTANTS 4-N-TRIDECYL-PYRIDINIUM AND 4-N-HEPTADECYL-PYRIDINIUM N-OXIDE IN WATER

The phase behaviour, liquid crystal structures and head group hydratio n of two 4-n-alkylpyridine-N-oxide surfactants have been studied using optical microscopy, DSC and H-2 NMR spectroscopy. Only a limited swel ling of the surfactant phase occurs in water, so that no micellar solu tion phase (L1) occurs. The lamellar phase is the only mesophase obser ved. Water (H-2) quadrupole splittings indicate that the head group bi nds c. 6 water molecules.