1. Physics Centre of Minho and Porto Universities (CF-UM-UP), Campus de Gualtar, University of Minho, 4710-057 Braga, Portugal
2. LaPMET Associate Laboratory, Campus de Gualtar, University of Minho, 4710-057 Braga, Portugal
3. Department of Polymer Engineering, Institute for Polymers and Composites (IPC), University of Minho, 4804-533 Guimarães, Portugal
4. Physics Department and CICECO, Campus de Santiago, University of Aveiro, 3810-193 Aveiro, Portugal
5. Centro de Investigación en Nanomateriais e Biomedicina (CINBIO), Universidad de Vigo, 36310 Vigo, Spain