1. Laboratory of Physical ChemistrySwiss Federal Institute of TechnologyETH Hönggerberg Vladimir-Prelog-Weg 2 8093 Zürich Switzerland
2. Present address: Cellulose & Wood MaterialsEmpa—Swiss Federal Laboratories for Materials Science and Technology Überlandstrasse 129 8600 Dübendorf Switzerland
3. Institut de Biochimie et Génétique CellulairesUMR 5095Université de Bordeaux 1, rue Camille Saint Saëns 33077 Bordeaux France