1. Laboratory of Physical Chemistry and Colloid Science, Wageningen University, Dreijenplein 6, 6703 HB Wageningen, The Netherlands, Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman B6a, 4000 Liège, Belgium, and Wageningen NMR Centre, Wageningen University, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands