1. Leibniz Institute of Polymer Research Dresden, Hohe Str. 6, 01069 Dresden, Germany
2. Department
of Physics, Mansoura University, Mansoura 35516, Egypt
3. Department
of Chemistry, Hamilton Hall, University of Nebraska-Lincoln, 639 North 12th Street, Lincoln, Nebraska 68588, United States
4. Physical
Chemistry of Polymer Materials, Technische Universität Dresden, 01062 Dresden, Germany