[1] Univ Groningen, Zernike Inst Adv Mat, NL-9747 AG Groningen, Netherlands
[2] Philips Res Labs, NL-5656 AE Eindhoven, Netherlands
[3] Eindhoven Univ Technol, NL-5600 MB Eindhoven, Netherlands
[4] Holst Ctr TNO, NL-5656 AE Eindhoven, Netherlands
[5] Russian Acad Sci, Enikolopov Inst Synthet Polymer Mat, Moscow 117393, Russia
[6] Graz Univ Technol, Inst Solid State Phys, A-8010 Graz, Austria