Optical Investigation of Single Perylene Diimides and their Application as Sensitive Probes in Soft Matter Science

Stefan Krause

One of the most suited probe molecule for soft matter investigations on a single molecule level is the perylene diimide-type system (PDI). This class of fluorophores features high quantum efficiency and photo stability. The emission properties of these dyes strongly depend on their backbone conformation which can be influenced by various functional groups. By choosing two types of environment – a clear SiO2 surface and a more rigid polymer matrix – the impact of spatial fluctuations of these functional groups could be investigated. In addition, the time-dependent reorientation dynamics of perylene diimide molecules at solid interfaces are discussed with respect to the number of pyrdiyl groups which allow for an attachment to surface silanols.

Finally, the photo physically investigated perylene diimides are utilized as sensitive probes in actively deformed poly(methylacrylate) and thin films of poly(styrene). In both cases the reorientation dynamics are investigated by means of polarization dependent fluorescence microscopy and give insight into the deformation behavior and micro viscosity of polymers on a single molecule level.