1. Department of Chemical Engineering; National Tsing Hua University; Hsinchu 30013 Taiwan Republic of China
2. Department of Electrical Engineering; National Tsing Hua University; Hsinchu 30013 Taiwan Republic of China
3. Institute of Polymer Research; Helmoltz-Zentrum Geesthacht; Max-Planck-Str. 1 Geesthacht 21502 Germany
4. Department of Materials Science Engineering; University of Ioannina; University Campus; Ioannina 45110 Greece