ON NATURE OF HYDROCARBON CHAIN MOTIONS IN LIPID LIQUID CRYSTALS

Consideration of the thermodynamic parameters of the crystal to liquid crystal transition for lecithins and of the fusion of molecules containing hydrocarbon chains allows a quantitative estimate of the configurational freedom of hydrocarbon chains in the liquid crystalline states at the transition temperature. For lipids in general, it appears that the chain mobility is intermediate between that of β (or β′) crystals and an n-alkane melt. The freedom of hydrocarbon chain motions is, however, greater in fully hydrated liquid crystalline systems than in anhydrous systems. These conclusions are pertinent to the much discussed question of hydrocarbon chain fluidity in thermotropic mesophases and certain biological systems. © 1969.