Physicochemical basis for water-actuated movement and stress generation in nonliving plant tissues

Luca Bertinetti, Franz-Dieter Fischer, Peter Fratzl

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Generating stresses and strains through water uptake from atmospheric humidity is a common process in nature, e.g., in seed dispersal. Actuation depends on a balance between chemical interactions and the elastic energy required to accomplish the volume change. In order to study the poorly understood chemical interactions, we combine mechanosorption experiments with theoretical calculations of the swelling behavior to estimate the mechanical energy and extract the contribution of the chemical energy per absorbed water molecule. The latter is highest in the completely dry state and stays almost constant at about 1.2 kT for higher hydrations. This suggests that water bound to the macromolecular components of the wood tissues acquires one additional hydrogen bond per eight water molecules, thus providing energy for actuation.
Original languageEnglish
Article number238001
Number of pages5
JournalPhysical review letters
Volume111.2013
Issue number23
DOIs
Publication statusPublished - 5 Dec 2013

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