MONTE-CARLO LATTICE SIMULATION OF THE INTERCHANGE OF CHAINS BETWEEN MICELLES OF DIBLOCK COPOLYMERS

The exchange of chains between micelles of diblock copolymers in dilut e solution has been studied using a dynamic Monte Carlo simulation. Ap propriate correlation functions have been defined and used to extract information from the trajectories. The picture of the dynamics depends on the definition of the correlation function, because different defi nitions are sensitive to different aspects of the overall dynamics of the system. The influence of concentration on the fundamental processe s, such as the extraction of a chain from a micelle and the addition o f a chain to a micelle, is studied. The tracer correlation function, w hich is defined in terms of the number of chains in an aggregate, show s a concentration dependence. In contrast, correlation functions defin ed for the extraction of a chain from a micelle and addition of a chai n to a micelle change very little for concentrations slightly above th e critical micelle concentration. An elaborated form of the correlatio n function for chain addition to a micelle. which differentiates the a rriving chain as a free chain or a participant in an aggregate at t = 0, shows a concentration dependence for the latter case. Another formu lation on the basis of fluorescence experiments has been set up consid ering each chain to be labelled either with a Forster donor or a Forst er acceptor. The resulting curves show that an increase in concentrati on leads to the relatively faster change in the efficiency of nonradia tive singlet energy transfer.