[1] Univ Ghent, Fac Engn & Architecture, Dept Mat Text & Chem Engn, Technol Pk Zwijnaarde 46, Ghent, Belgium
[2] Dutch Polymer Inst DPI, POB 902, NL-5600 AX Eindhoven, Netherlands
[3] Natl Phys Lab, Dept Engn Mat & Elect Sci, Teddington TW11 0LW, Middx, England