DIRECT IMAGING SINGLE-MOLECULE DIFFUSION IN A SOLID POLYMER HOST

The time evolution of the microscopic lateral diffusion and dynamic re orientation of individual dye molecules dispersed in a thin polymer fi lm is probed by means of scanning near-field optical microscopy at roo m temperature and ambient conditions, On a sub-micrometer scale we ide ntify regions where the diffusion is drastically non-random, while the statistical average of the trajectories of 97 molecules in a 4 mu m x 4 mu m section displays random-walk behavior.