Effect of Confinement on the Thermodynamics and Structure of semi-crystalline Polymers
Martin Rosenthal
Institut de Chimie des Surfaces et Interfaces, UPR 9069 CNRS, Mulhouse, France
I’m a PhD student working at the “Institut de Chimie des Surfaces et Interface” in Mulhouse (France) within the Marie Curie Research Training Network (RTN) “Polyfilm”.
I graduated in “Materials Science and Engineering” from the “Martin Luther” University in Halle-Wittenberg, with a curriculum focused on physical and technological aspects of polymer science and applications. In the summer of 2001 I spent 2 months at the University of Massachusetts in Amherst, Massachusetts in the Department of Polymer Science and Engineering. This summer research project dealt with the formulation and characterization of poly(vinyl alcohol) (PVA) nano-particles for biomedical applications. During my main studies I worked in the Group of Prof. Goerg H. Michler focusing on optimization of Tapping Mode investigations by scanning force microscopy (TMAFM) on polymeric samples for in-situ characterization of micromechanical deformation mechanisms of semi-crystalline polymers.
In October 2003, I joined The Dow Chemical Company in Terneuzen, Netherlands for a half year training in the group of PD Dr. Georg Bar working on the development and validation of improved work processes for morphology characterization of polymers by TMAFM.
My final project was collaboration with The DOW Chemical Company, dealing with adhesion and failure mechanisms of bicomponent fibers in nonvowen fiber fabrics by means of microscopic techniques, acquiring experience in the common electron and force microscopic techniques.
Fig.1: Banded spherulites of PTT grown from the melt, as viewed with confocal laser scanning microscopy
During my PhD work I will study the effect of confinement on the thermodynamics and organization of semi-crystalline polymer structures. The aim is to monitor and characterize the formation and structure of crystals in thin polymer films and their deviation from the bulk.
The reciprocal space information on polymer structure and organization obtained by time- and temperature resolved wide- and small-angle X-ray scattering will be complemented by imaging techniques such as Transmission Electron Microscopy (TEM) and Scanning Force Microscopy (SFM).
Mapping the film in two orientations, normal and transverse of the sample with respect to the film surface, will allow us to study the microstructure of lamellar bundles oriented at different angles with respect to the surface of the film.
Fig.2: 2D SAXS (Top) and WAXS pattern (Bottom) of poly(trimethylene terephthalate) PTT 2D spherulites confined in a films of several microns thickness crystallized at 190°C measured in transverse direction at 190°C (left); Temperature dependence of the radial integrated scattering intensity respectively (right)
In this way, the time- and temperature-resolved SAXS and WAXS experiments will allow discrimination of the structure and thermal behaviour of the crystals having different orientations.
