| Nanostructured Shielding material, made from polyacrylonitrile (PAN) and dimethyl formamide (DMF) covered with a copper-20 wt.% tin alloy, was produced combining sputtering and electrospinning techniques, with the aim to generate a thin film capable to attenuate electromagnetic interferences (EMI) on a range similar the one used by cellular devices. A 24 performed to produce the polymeric nanofibers with a small diameter employed as templates. Alloy deposition was conducted by sputtering, where the time was selected as the control variable, while other intrinsic variables were set constant. The amounts of metal deposited was measured in terms of thickness steps, with a contact profilometer over masked silicon substrates. Produced composites of PAN nanofibers with diameters of around 130 nm, coated with 5, 20 and 100 nm alloy, were characterized by a scanning electron microscope (SEM), energy dispersive pectroscopy (EDS) and X-ray diffraction (XRD) in order to observe their morphology and the metallic alloy presence over the templates.;The shielding effectiveness (SE) was measured employing a pair of loops antennas connected at a spectrum analyzer; a method easy to run, which needs little specimen preparation. The results for the proposed metal thickness, were in the order of 7 dB for the material covered with 100 nm alloy, then an additional sample covered with 300 nm alloy was tested for electromagnetic interference shielding with a SE of 20 dB at two specific points, 811 MHz and 1.24 GHz. These results do not promote the manufactured material as a good shielding material, but opens the door towards new attempts with conductive polymeric materials, covered with other metal alloys looking for better SE results. |
