Polypyrrole/Graphene Oxide Films Based Microwave Absorbing Fabric Through Layer-by-layer Assembly

Electromagnetic wave radiation, which interferes with the electronicdevices, also throws great threaten to humans’ health. Meanwhile therequirements for new electromagnetic wave shielding materials arethinness, lightweight, broad range, and strong absorptivity which arebeyond the properties of traditional electromagnetic wave shieldingmaterials. In the view of research about electromagnetic wave shieldingmaterials and the prospective development of new materials, grapheneoxide (GO) will be a potential candidate for electromagnetic waveshielding materials because of the easy processibility, high mechanicalstrength and extreme thinness. At the same time through layer-by-layer(LbL) assembly, which provides a feasible technique, functional films withcontrolled thickness, specific structure, variable shapes can be obtained. Inthis study, grapheneoxide based multilayer films coated on fabrics throughlayer-by-layer assembly enjoys enhancing electromagnetic wave shieldingproperty. This multilayer films, which are very thin, put up a newperspective for the investigation of new electromagnetic wave shielding martials.Graphene oxide (GO) was synthesized by modified Hummers method.Thethickness of GO is around1.5nm from the AFM image data and the d-spacing of graphene oxide nanosheets is around0.84nm. The results ofFT-IR spectrum show the the existence of oxygen groups such as COOH,OH in GO, and the solution of GO is extremely stable with a zeta potentialless than-40mV.The structure and the element component of the Polypyrrole/Grapheneoxide ((PPY/GO)n) multilayer films through layer-by-layer assembly, wasinvestigated.The results show the linear growth mechanismof (PPY/GO)nmultilayerfilmsandthethicknessof(PPY/GO)4filmisaround68.20±6.79nm. The interaction between GO and PPY was manifested by FT-IR andthe existence was confirmed by XPS.The fabrics coated with (PPY/GO)n multilayer films was prepared bylayer-by-layer assembly technique and the relationship of electromagneticwave shielding efficiency (SE) and the numbers of coated layers wasinvestigated. The results show the amount of (PPY/GO)n multilayer filmswill increase with increasing the number of coated layers. Theelectromagnetic wave shielding efficiency of (PPY/GO)5multilayer films,which has a surface resistivity around23.8Ω/sq, embraces a higher value(around25.2dB) than the shielding efficiency of (PPY)5multilayer films(around15dB).Inaddition theabsorptivityof(PPY/GO)nmultilayerfilms is more than50%, indicating the absorption mechanismof electromagneticwave shielding of (PPY/GO)n multilayer films.Another three different parameters were considered when preparing the(PPY/GO)n multilayer films coated fabrics which are surfactant (SDBS),temperature of polymerization of pyrrole (0℃), and the pH value of FeCl3.The datas indicate the fabric coated with (PPY/GO)n multilayer films inwhich polypyrrole was synthesized under ice bath (0℃), shows highestshielding efficiency (maximumvalue around19dB) among of others.Alsothe fabrics prepared under different conditions show a absorptionmechanism.According to the data and results of this study, the (PPY/GO)nmultilayer films which embrace an elevated electromagnetic waveshielding efficiency provide a new prospective for the application andresearch of electromagnetic wave shielding materials.