EMI shielding composites based on magnetic nanoparticles and nanocarbons

• Autores: María Crespo Ribadeneyra
• Directores de la Tesis: María González González (dir. tes.), Javier Pozuelo de Diego (dir. tes.)
• Lectura: En la Universidad Carlos III de Madrid ( España ) en 2014
• Idioma: inglés
• Tribunal Calificador de la Tesis: Humberto Terrones (presid.), Juan José Vilatela García (secret.), Raquel Verdejo Márquez (voc.)
• Materias:
  • Física
    • Física del estado sólido
      • Materiales compuestos
    • Física teórica
      • Radiación (electromagnética)
  • Química
    • Química inorgánica
      • Carbono
• Enlaces
  • Tesis en acceso abierto en: e-Archivo
• Resumen

  • The response of nanocomposites towards electromagnetic (EM) radiation can be tailored through the electrical conductivity, permittivity and magnetic permeability. Several composites with singular microstructures and containing either conductive nanoinclusions, magnetic nanoparticles or the combination of both, have been prepared and characterized. The performance of our materials as EM interference (EMI) shields, has been determined from 1 to 18 GHz and elucidated in terms of their electric and magnetic behavior. Cu -- Ni ferrite nanoparticles with varying stoichiometry were synthesized inside the pores of micro-silica particles. This inusulating, multiscale reinforcement was used to prepare epoxy composites. The EMI shielding performance of these materials was studied in order to determine the specific role of the magnetic nanoinclusions. The combined effect of magnetism and conductivity in EMI blocking was studied in composites containing magnetite nanoparticles and carbon nanofibers (CNFs) or carbon nanotubes (CNTs). These latter were assembled into three-dimensional architectures (CNT-scaffolds and CNT-sponges) to study the interconnectivity between CNTs with regard to EMI shielding. In CNT-scaffolds, nanotubes were post-assembled with a polymeric binder. These structures showed that the conductivity and shielding ability could be up-shifted without increasing the reflectivity, since good CNT-interconnectivity is achieved at low nanotube loads. In CNT-sponges, it was observed that enhanced contact between nanotubes further improves EM blocking within the entire frequency range.