1. Division of Fibre Technology Department of Fibre and Polymer Technology KTH Royal Institute of Technology Stockholm 10044 Sweden
2. A. J. Drexel Nanomaterials Institute Department of Materials Science and Engineering Drexel University Philadelphia PA 19104 USA
3. Department of Materials and Environmental Chemistry Stockholm University Stockholm 10691 Sweden
4. Wallenberg Wood Science Centre Department of Fibre and Polymer Technology KTH Royal Institute of Technology Stockholm 10044 Sweden