Graphene nanoplatelets based nanocomposites for EMI Shielding applications
Ioan Valentin Tudose1,2,4, Kyriakos Mouratis1, George Kenanakis2, Mirela Suchea1.3* and Emmanouel Koudoumas1*
1 Center of Materials Technology and Photonics, School of Engineering, Hellenic Mediterranean University, 71410 Heraklion, Crete, Greece
2 Institute of Electronic Structure and Laser, Foundation for Research & Technology-Hellas, Heraklion, Crete, Greece
3 National Institute for Research and Development in Microtechnologies-IMT Bucharest, 126A, Erou Iancu Nicolae Street, 077190 Voluntari-Bucharest Romania
4 Chemistry Department, University of Crete, 70013, Heraklion, Greece
Electromagnetic frequencies can affect many sensitive electronics, and can cause a wide variety of different issues from a simple noise on a communication line, to a total disruption of a safety-critical signal. It affects a diverse range of sectors, including consumer and industrial electronics as well as critical systems for military and emergency services. The most common type of EMI occurs in the radio frequency (RF) and microwave (MF) ranges of the electromagnetic (EM) spectrum, from 1kHz to 1THz. One way to solve these problems is by using shields. Shields are devices, when put around devices, prevent interference. These shields can prevent interference from either a device generating interference out to the world or the device picking interference from outside sources. Shielding effectiveness of a material is the ratio of impinging energy to the residual energy. Shielding effectiveness is the ratio of the field before and after attenuation and it is dependent on frequency. The attenuation of an electromagnetic wave occurs by absorption, reflection or multiple reflections and the shielding effectiveness is the summation of these 3 phenomena. In order to be suitable for EMI shielding applications a material should have the ability to absorb, reflect or multiple reflect the electromagnetic radiation of a specific wavelength or a frequencies domain. The usual EMI shielding materials are metals, alloys and metallic coatings onto various supports but they are heavy and difficult to manipulate and this makes them undesirable despite their great EMI shielding ability. To overcome this inconvenience, electrically conductive carbon-based materials that are of low density and enough conductive to promise quite effective EMI shielding. Some composites of conductive carbon/graphite were used but they proved to be very brittle. They are usually used as conductive fillers in various insulating matrices (such as rubbers, resins and polymers) otherwise transparent to electromagnetic radiation. The present presentation reports on graphene-based paints for EMI SE applications. Various combinations of graphene nanoplatelets, polyaniline (PANI) doped with polystyrene sulphonic acid (PSS) and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) were employed using water and alcohol bases for paints. The new paint-like nanocomposite layers consisting on these components combinations can offer quite effective electromagnetic shielding, similar or even better than that of commercial products, the response strongly depending on their thickness and resistivity.
This work was partially supported by NATO SPS project number: G5477 NATO Science for Peace and Security (SPS) Programme.