Regensburg 2013 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 18: Poster: Polymer Dynamics

CPP 18.11: Poster

Dienstag, 12. März 2013, 18:15–20:15, Poster C

A Detailed Study on Heterogeneous Dynamics in Polymers Close to Tg by SM Techniques — •Subhasis Adhikari, Markus Selmke, and Frank Cichos — Inst. of Expt. Physics I, University of Leipzig,Germany

The temperature dependent rotational dynamics of a single perylene dimide (PDI)dye molecule in Poly (methyl acrylate)(PMA) and in poly (vinyl acetate) (PVAc) have been studied. The autocorrelation of linear dichroism (LD) of a single PDI molecule is stretched exponential. The dynamics of a single probe molecule is temporally heterogeneous. The rotational times and stretching exponents are widely distributed. All SM results are discussed using a simple model of dynamical heterogeneity based on a Gaussian distribution of activation energies. SM average rotational times follow Debye - Stokes - Einstein (DSE) law for polymer viscosity. Dielectric measurements shows that probe rotation may or may not couple to segmental motion. Probe with different size follow same temperature dependence as predicted from DSE law.

Detailed information on heterogeneous dynamics is further expected from an extension of two - point nanorheology to single molecule optical studies based on fluorescence resonance energy transfer (FRET). We have therefore synthesized bi - labeled (Alexa 488 and Alexa 594) polystyrene polymer. Lifetime and intensity based smFRET are reported.