Berlin 2012 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 25: Poster: Stress Relaxation in Polymers - From single molecules to biological cells (joint focus with BP)

CPP 25.2: Poster

Mittwoch, 28. März 2012, 11:00–13:00, Poster A

Characterization of conformational changes of single-chain, thin film and bulk polymers — •Frank Zocholl¹, Massimiliano Labardi², Daniele Prevosto², Kirsten Dammertz¹, Masoud Amirkhani¹, and Othmar Marti¹ — ¹Institute of Experimental Physics, University of Ulm, 89069 Ulm, Germany — ²Dipartimento di Fisica Enrico Fermi, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy

The possibility to induce conformational changes in Poly(4-Vinylpyridine) (P4VP) by application of ambient gas or electric fields is investigated. Characterization of dielectric properties both in bulk and thin films of P4VP are carried out by dielectric spectroscopy techniques, to find information about glass transition temperature and relaxation processes. Broadband Dielectric Spectroscopy (BDS) is a well established technique for dielectric study of bulk samples. Local Dielectric Spectroscopy (LDS) is a new approach based on Atomic Force Microscopy (AFM), applicable to ultra-thin films and capable of high spatial resolution, by sensing electric forces between the sample and the AFM tip. By means of a customized setup, shifts in instantaneous resonance frequency of the force sensor due to an ac applied voltage are measured, and provide information on the dielectric function of the material. By measuring dielectric relaxation dynamics for various thicknesses it is possible to evidence the effects of both spatial confinement and presence of interfaces.