Nanoscale Imaging of the Interface Dynamics in Polymer Blends by Femtosecond Pump-Probe Confocal Microscopy

A polymer blend of a polyfluorene and an inert matrix is imaged with an innovative time-resolved confocal microscope. Local pump-probe signals (excited-state generation and deactivation) with sub-200-fs temporal resolution and 300-nm spatial resolution are measured. Peculiar dynamics at the interface between the segregated domains, invisible to standard optical microscopy, due to different inter-chain interactions and charge separation photophysics are detected.