1. Centro de Fisica Aplicada y Tecnología Avanzada (CFATA)Universidad Nacional Autonoma de Mexico, Campus Juriquilla, Queretaro, CP 76230, Mexico
2. Laboratory of Advanced Polymers & Optimized Materials (LAPOM)Department of Materials Science & Engineering, University of North Texas, 1150 Union Circle 305310, Denton, TX 76203-5017, USA