Temperature induced phase transitions in lipid bilayer models

Abstract Different types of n-alkyl containing compounds have been studied by temperature controlled single crystal x-ray diffraction. They crystallize in layers of alkylammonium ions alternating with layers of counter ions. The organic layers mimic liquid crystals of the smectic type or bilayers as found in biomembranes. These compounds exhibit numerous phase transitions which are due mainly to different chain conformations. In one example, the transitions preceding the melting of the chains has been analysed step by step and shows the evolution of the various chain conformations. In another example, evidence has been found of the separation of the chains from an intercalated type of packing to a non-intercalated type.