Trap fluorescence experiments for the study of interfacial structure.

A theory for electronic excitation transport in inhomogenous systems is developed that will allow trap fluorescence experiments to be used to probe interfacial structure in phase separated binary polymer blends. We consider a two-phase system in which polymer A is labeled with trap chromophores and polymer B is labeled with donor chromophores. Experiments are proposed that involve optical excitation on the donor species at time zero and observation of the subsequent trap fluorescence at later times. A theoretical expression for the transient trap fluorescence intensity is derived that depends on the interfacial profile. We anticipate that the experiments will be quite sensitive to the interfacial thickness, but probably not to the details of the profile.