P1

P1: Constrained Single Molecule Dynamics in Glassy Polymer Systems

A drastic slow down of the dynamics of a liquid when approaching the transition to a disordered amorphous solid state is common to a vast variety of systems. These involve the simple molecular fluids of small molecules and extend to complex polymeric or polyelectrolyte systems and even to the cells’ network of structural filaments. All of these systems have two things in common: structural disorder and metastability, which define the still not well understood complexity of the systems’ dynamics. Within this study, we will explore the slow dynamics in simple synthetic polymers close to their glass transition. Employing single molecule detection techniques, we will obtain spatial and temporal resolution of the heterogeneous dynamics, which should give a more detailed molecular picture of slow dynamics in glassy systems. A wealth of new information in the heterogeneous dynamics is expected from an extension of the two point micro-rheological measurement techniques to single molecule optical studies. This new technique will be based on fluorescence resonant energy transfer to access a length scale of about 10 nm, which is currently not accessible by other rheological methods! The development of these methods can be of benefit to other studies within this research unit which also aim to probe spatially heterogeneous dynamics on a molecular scale as e.g. in membrane systems.