[Non-isothermal pattern of phase transition in vesicle membranes]

Phase transition of lipid molecules between liquid and crystalline states in the vesicle membrane has a non-isothermal pattern; it is spread in some temperature range, which depends on the vesicle size. With a change of phase transition the area which falls within a lipid molecule is changed. As a result elastic tensions appear in the membrane. They may account for the non-isothermal pattern of phase transition. The number of molecules in each state is calculated in relation to temperature, and the temperature range is calculated within which the phase transition is realized. The smaller is the vesicle radius, the higher is the temperature range value. Temperature relationship of the membrane heat capacity at non-isothermal phase transition is calculated. The obtained results well agree with the number of experimental data.