1. Energy Research Centre of The Netherlands (ECN), P.O. Box 1, 1755 ZG Petten, The Netherlands
2. Fraunhofer-Institute for Applied Polymer Research, Geiselbergstr. 69, D-14476 Golm, Germany
3. Energy Research Centre of The Netherlands (ECN), P.O. Box 1, 1755 Petten, The Netherlands