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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 48: Poster: Polymer Crystallization, Nucleation and Selfassembly

CPP 48.7: Poster

Mittwoch, 22. März 2017, 18:30–21:00, P2-OG1

Formation of periodically modulated single crystals of isotactic polystyrene — •Purushottam Poudel, Sumit Majumder, and Günter Reiter — Physikalisches Institut, Albert-Ludwigs- Universität Freiburg, Hermann-Herder-Straße 3, D-79104 Freiburg, Germany

Polymer crystals are often composed of stacks of lamellae, separated by amorphous layers. The underlying mechanism of self-induced nucleation of secondary lamellae is at the origin of crystal growth in the direction of the surface normal of the lamellae, generating three-dimensional (3-D) stacks of lamellar crystal. In order to explore such growth of 3-D crystals consisting of correlated lamellae, we have chosen thin films of isotactic polystyrene. Interestingly, we observed the formation of periodically modulated crystalline structures consisting of stacks of correlated lamellae. The spacing between such stacks, i.e. the period, was found to increase with increasing crystallization temperature and film thickness. Detailed investigations via atomic force microscopy revealed that the periodically modulated structures resulted from the interplay between nucleation of stacks of secondary lamellae, growth of these lamellae and diffusion of polymer chains.