Nano-imaging of polymers by optical microscopy

The developments of laser scanning confocal microscopy (LSCM) and scanning near-field optical microscopy (SNOM) have expanded the application range of optical microscopy from micron to nanometer dimensions, in which the molecular and macromolecular materials exhibit intrinsic fundamental characteristics closely related to their functionality. Although atomic force and electron microscopes have often been utilized for observing materials in nanometer dimensions, the world of the critical length (10-100 nm) of nano-technology and science is now illuminated by "light", and is revealed as real optical images from different points of view associated with not only morphology but also spectroscopic, analytical, time-resolved and opto-electrical responses in a local space. This article reviews the recent findings made by LSCM and SNOM mainly in terms of morphology of polymeric materials; particular concerns are in the phase-separated structures of polymer blends, conformation and morphology of a single polymer chain, and also two-dimensional ultra-thin polymer films. These optical techniques will become an indispensable tool for understanding molecular and biological systems.