Fluorescence Probe Method for Investigating Polymer Structures in Nanometer Dimensions

The applications of the optical methods using fluorescent probes for investigating polymer structure and dynamics at a molecular level are reviewed. The versatile and particular abilities of the fluorescence method have been exemplified using ultrathin films made of polymer monolayers, which provided fine model systems designed with a nanometer precision. In the latter part of this article, the emerging research field of scanning near-field optical microscopy (SNOM) is introduced. This novel microscopic technique enabled us to carry out spectroscopic and time-resolved measurements with a lateral resolution of 100 nm, which is obviously beyond the diffraction limit of light. We applied SNOM to study various nanometer-scale structures of polymer assemblies, such as the two-dimensional phase separation structure, morphology of single polymer chains, and structural inhomogeneity of polymer networks. These results showed that the combination of the fluorescence method and SNOM technique will open a new field of research on polymeric materials by providing molecular information on the basis of real optical images on a nanometric scale.