Nature’s Nanocomposites: A New Look at Molecular Architecture

A widely-accepted model for the molecular architecture of wood fails to account for the stick-slip deformation process, in which wet wood shows permanent plastic deformation without signifi cant mechanical damage. A proposed model interposes a layer of water molecules between cellulose microfi brils and the surrounding matrix. Results from proton spin diffusion, monitored via 13C NMR signal strengths, supported the new model. Pinus radiata D.Don latewood was soaked in D 2 O and a timescale of 10 ms was measured for proton spin diffusion between cellulose and glucomannan. This observation was interpreted in terms of a layer of D 2 O molecules creating a spin-diffusion barrier between the microfi brils and the matrix