Stochastic Theory of Nonequilibrium Phase Transitions. Application to Phospholipid Bilayer Membranes.

摘要

In this paper the kinetics of phase transitions of the first kind are studied in separable systems. The equilibrium and nonequilibrium phase transitions of the whole separable system have been characterized by the processes that take place within an independent subsystem of the separable system. The nonlinear, coupled stochastic equations have been solved numerically by means of Adam's method. The processes were generated by three different types of temperature changes: linear/heating/cooling, temperature jumps, and sinusoidal temperature oscillations. Processes from unstable to stable status states start with increasing velocity, but after reaching an inflection point at time ti1, the processes slow down exponentially. Processes from metastable to stable states exhibit more complicated kinetics. This is the regime of the process increases until the first inflection point at time ti1, and then the process slows down to a locally minimum velocity at ti2. Then the velocity increases again till the third inflection point at ti3, and finally slows down exponentially to zero velocity. These theoretically predicted kinetics were also obtained for the crystalline to gel phase transition of dipalmitoylphosphatidylcholine (DPPC) membranes. Reprints. (aw)