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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 40: Polymer Crystallization and Semicrystalline Polymers

CPP 40.8: Vortrag

Donnerstag, 17. März 2011, 12:30–12:45, ZEU 160

How Do Extended Chain Crystals Affect the Surface Morphology of Diblock Copolymers? — •Thomas F. Keller, Stefan Watzke, Robert Schulze, and Klaus D. Jandt — Institute of Materials Science and Technology (IMT), Friedrich-Schiller-University Jena, Germany

Recently, in short chain double-crystalline diblock copolymers several temperature-dependent morphologies were reported, which are suppressed in similar high molecular weight copolymers. These morphologies were attributed to extended chain crystals with enhanced chain mobility at the interfacial boundary to neighboring domains.

The aim of the presented study was to test the hypothesis that these temperature-dependent morphologies form on the surface of thin films of such copolymers, and to investigate the phase separation as well as the nucleation and crystal growth behaviour.

By in-situ atomic force microscopy (AFM) we analyzed the temperature-dependent surface morphology of thin films of a short chain polyethylene-block-poly(ethylene oxide) copolymer. When cooling from the melt we observed a heterogeneous surface morphology. Needle-like plates formed. In between these needle-like plates a perpendicular lamellar morphology gradually built up.

A model to describe these observations is discussed, which bases on the formation of extended chain crystals. The current study shows how this formation of extended chain crystal induces new heterogeneous nanostructured copolymer surfaces for potential applications, such as in the biomedical field.