1. Department of PhysicsUniversity of North Texas, Denton, TX 76203, USA
2. Laboratory of Advanced Polymers & Optimized Materials Department of Materials Science and Engineering and Department of Physics, University of North Texas, 3940 North Elm Street, Denton TX 76207, USA
3. Braskem America Inc., 550 Technology Drive, Pittsburgh PA 15219, USA
4. PerkinElmer Analytical SciencesShelton, CT 06484, USA