GROWTH OF MOLECULAR SUPERLATTICE IN FULLY HYDRATED DIPALMITOYLPHOSPHATIDYLCHOLINE DURING SUBGEL PHASE-FORMATION PROCESS

Recently, it has been reported that the structure of the subgel phase of dipalmitoylphosphatidylcholine (DPPC) is characterized by two latti ces, i.e., a hydrocarbon lattice and a molecular superlattice [1]. On the basis of the results, the domain growth of the molecular superlatt ice in fully hydrated DPPC multilamellar vesicles at 2.5 degrees C was studied by means of X-ray diffraction. The change of the intensities of the (11) diffraction peak originated from the molecular superlattic e was analyzed by the Kolmogorov-Avrami theory. We found that the effe ctive dimensionality of the growing domains is 2.3 +/- 0.4. This resul t indicates that the domains of the molecular superlattice grow two-di mensionally during the subgel phase formation process, i.e., the domai n grows in a single bilayer and is independent between the domains in adjacent bilayers.