Münster 1999 – scientific programme

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CP: Chemische Physik

CP 32: Poster: Einzelteilchenspektroskopie

CP 32.5: Poster

Monday, March 22, 1999, 18:00–20:00, R52/R72

Probing Highly Oriented Polymers at the Single Molecule Level — •Werner Trabesinger¹, Beate Sick¹, Bert Hecht¹, Urs P. Wild¹, Andrea Montali², Christoph Weder², and Paul Smith² — ¹Institute for Physical Chemistry, ETH Zurich, — ²Institute of Polymers, ETH Zurich

PPE (poly-phenylene-ethynylene) derivatives (EHO-OPPE) incorporated into

films of polyethylene

(PE) can serve as efficient active polarizers in liquid crystal

displays. Stretching

of the material leads to alignment of the

linear PE molecules along the stretching axis presumably inducing

an orientation of the EHO-OPPE molecules along the same axis.

Improving the performance of such devices requires a detailed

understanding of the stretching process. At the bulk level

(high concentrations of EHO-OPPE), questions concerning the

degree of orientation or the possibility of phase separation

(clustering of the EHO-OPPE molecules) cannot be addressed

adequately. We present measurements using fluorescence scanning

confocal optical microscopy on films with extremely low

EHO-OPPE concentrations, demonstrating that it is possible to

observe these polymers at the level of single molecules. Our observations support the orientation of the EHO-OPPE molecules due to

stretching. Finally, we address the issue of clustering of these

molecules and present polarization measurements.