title: Carbon nanotube scaffolds with controlled porosity as electromagnetic absorbing materials in the gigahertz range.
abstract: Control of the microscopic structure of CNT nanocomposites allows modulation of the electromagnetic shielding in the gigahertz range. The porosity of CNT scaffolds has been controlled by two freezing protocols and a subsequent lyophilization step: fast freezing in liquid nitrogen and slow freezing at -20 °C. Mercury porosimetry shows that slowly frozen specimens present a more open pore size (100-150 μm) with a narrow distribution whereas specimens frozen rapidly show a smaller pore size and a heterogeneous distribution. 3D-scaffolds containing 3, 4, 6 and 7% CNT were infiltrated with epoxy and specimens with 2, 5 and 8 mm thicknesses were characterized in the GHz range. Samples with the highest pore size and porosity presented the lowest reflected power (about 30%) and the highest absorbed power (about 70%), which allows considering them as electromagnetic radiation absorbing materials.
authors.affiliation: Departamento de Ciencia e Ingeniería de Materiales e Ingeniería Química (IAAB), Universidad Carlos III de Madrid, 28911 Leganés, Madrid, Spain. jpozue@ing.uc3m.es.
authors.forename: M
authors.initials: M
authors.lastname: González
authors.affiliation: Departamento de Ciencia e Ingeniería de Materiales e Ingeniería Química (IAAB), Universidad Carlos III de Madrid, 28911 Leganés, Madrid, Spain. jpozue@ing.uc3m.es and School of Engineering and Materials Science, Queen Mary, University of London, 327 Mile End Road, London, UK.
authors.forename: M
authors.initials: M
authors.lastname: Crespo
authors.affiliation: Departamento de Ciencia e Ingeniería de Materiales e Ingeniería Química (IAAB), Universidad Carlos III de Madrid, 28911 Leganés, Madrid, Spain. jpozue@ing.uc3m.es.
authors.forename: J
authors.initials: J
authors.lastname: Baselga
authors.affiliation: Departamento de Ciencia e Ingeniería de Materiales e Ingeniería Química (IAAB), Universidad Carlos III de Madrid, 28911 Leganés, Madrid, Spain. jpozue@ing.uc3m.es.
authors.forename: J
authors.initials: J
authors.lastname: Pozuelo