Regensburg 2007 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 35: SYBM Bioinspired Materials

MM 35.6: Talk

Thursday, March 29, 2007, 16:15–16:30, H16

The actuation of organ movement by the generation of tensile and compressive stresses in wood cell walls — •Ingo Burgert, Michaela Eder, Notburga Gierlinger, and Peter Fratzl — Max Planck Institute of Colloids and Interfaces, Department of Biomaterials, 14424 Potsdam, Germany

Active movement is usually associated with animals rather than plants. Plants do not have muscles, but they are able to pre-stress their tissues in order to actuate their organs. Here, we demonstrate for softwoods that either tensile or compressive stresses can be obtained during swelling of the cell wall. This can be well understood by simple mechanical considerations, taking into account the cell shapes and the observed cellulose fibril orientations. The almost inextensible cellulose fibrils redirect the forces generated by the swelling of the matrix by purely geometrical constraints to produce tension or compression forces according to needs. This principle could be simple enough to be reproduced in artificial systems and one may consider developing fiber-reinforced hydrogels as effective microactuators. The main technical challenge would be to reproduce the well controlled fiber orientation found in wood cells.