Berlin 2008 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 20: POSTERS Driven Soft Matter

CPP 20.23: Poster

Mittwoch, 27. Februar 2008, 16:00–18:30, Poster A

memory in paste and its application to control crack pattern — •akio nakahara and yousuke matsuo — Nihon University, Funabashi, JAPAN

We experimentally find that paste (densely packed colloidal suspension) has memories of external mechanical fields such as vibration and flow. There is a transition in memory from memory of vibration to memory of flow as we decrease a volume fraction of colloidal particles in paste. These memories in paste are maintaned as anisotropic microstructures, and can be visualized as crack patterns which emerge when the paste is dried. When paste has a memory of vibration, the direction of crack propagation becomes perpendicular to the direction of the vibration. On the other hand, when paste has a memory of flow, the direction of crack propagation becomes parallel to the direction of the flow [1].

By using these memory effects, we can imprint direction of crack propagation into paste to control and produce various crack patterns, such as cellular, lamellar, radial, ring, spiral, and so on.

[1] A. Nakahara and Y. Matsuo, Phys. Rev. E 74, 045102(R) (2006).