Fluorescence depolarization due to excitation energy migration in polymeric micelles: A Monte Carlo study

Cores of block copolymer micelles have been studied by Monte Carlo simulati on. Core-forming chains have been modeled as self-avoiding chains enclosed in a spherical cavity and tethered to its surface. ii fraction of the untet hered end segments of chains (18-53%) has been treated as fluorescent probe s. The time-dependent solution of the Pauli master equation that describes excitation energy migration among probes has been averaged in an ensemble o f 10(4) simulated cores. We have studied the dependence of the depolarizati on function G(S)(t), i.e., the probability that the originally excited prob e is still excited at time t, on the chain length and on the energy migrati on critical radius of the probe. Cores with randomly solubilized probes and with clusters of probes have been also studied for comparison.