2001-12-05
10:15 at ML H43

Modelling rhythmic and anisotropic growth of crystals

Jan van Meerveld

Institute of Polymers, ETH Zurich

Spherulites show a typical banding under crystallization. This topic has been a long debate depending on either the molecular ordering (skrew dislocation) and 'stress' relaxation. Recently Kyu et al. (PRL, 83(14), pp 2749, 1999) proposed a phenomenological expression for the free energy solved via the Ginzburg-Landau expression. Qualitative correspondence with experimental observations is obtained. The same authors furthermore describe different crystal shapes depending on an anisotropic Landau contribution. Using GENERIC one is able to generalize these equations to convective conditions and furthermore obtain the appropriate stress expression. The last may confirm to the longstanding claim that anisotropic crystals are induced by anisotropic surface contributions.