1. Laboratory of Materials and Interface Chemistry and Soft-Matter CryoTEM Research Unit and Laboratory of Polymer Technology, Eindhoven University of Technology, PO Box 513, NL-5600 MB Eindhoven, The Netherlands, Dutch Polymer Institute, Eindhoven University of Technology, PO Box 902, NL-5600 AX Eindhoven, The Netherlands, and FEI Company, Achtseweg Noord 5, Building AAE, 5600 KA Eindhoven/Acht, The Netherlands