1. Laboratory for Physical Chemistry and Colloid Science, Wageningen Agricultural University, P.O. Box 8038, 6700 EK Wageningen, The Netherlands
2. Akzo Nobel Central Research Arnhem, Velperweg 76, P.O. Box 9300, 6800 SB Arnhem, The Netherlands
3. Akzo Nobel Chemicals Arnhem, Westervoortsedijk 73, P.O. Box 9300, 6800 SB Arnhem, The Netherlands