To diminish electromagnetic interference (EMI) for microwave radiations, effects of graphite (Gr) modified by a long alkyl chain ionic liquid (IL) 1-Butyl-3-methylimidazolium hydrogen sulphate ([BMIM][HSO4]) on poly(vinylidene fluoride) (PVDF), was investigated. The pre-localized Gr coated polymer powders were fabricated, using solvent blending method, with different concentrations of Gr over PVDF matrix to prepare a series of PVDF/Gr/IL composites. The surface morphology of the fabricated composite films was examined by scanning electron microscopy (SEM). The composites, with a thickness of ~0.15 mm, exhibit good EMI shielding properties, besides low cost production and flexibility. The enhanced properties are due to high ionic conductivity of the IL and formation of a connecting network by Gr facilitating electron conduction. Absorption is the key factor due to which the total shielding effectiveness in the frequency band of 12 to 18 GHz has been improved significantly.
2. Geetha, S., K. K. Satheesh Kumar, C. R. K. Rao, M. Vijayan, and D. C. Trivedi, "EMI shielding: Methods and materials — A review," Journal of Applied Polymer Science, Vol. 112, No. 4, 2073-2086, May 2009.
3. Morgan, D., Handbook of EMC Testing and Measurement, Vol. 8, Institution of Electrical Engineers (IEE), London, 1995.
4. Kheifets, L., A. A. Afifi, and R. Shimkhada, "Public health impact of extremely low frequency electromagnetic fields," Environ. Health Persp., Vol. 114, No. 10, 1532-1607, Oct. 2006.
5. Rathi, V., V. Panwar, G. Anoop, M. Chaturvedi, K. Sharma, and B. Prasad, "Flexible, thin composite film to enhance the electromagnetic compatibility of biomedical electronic devices," IEEE Transactions on Electromagnetic Compatibility, Vol. 61, No. 4, 1033-1041, Nov. 2018.
6. Song, W. L., X. T. Guan, L. Z. Fan, W. Q. Cao, C. Y. Wang, and M. S. Cao, "Tuning three-dimensional textures with graphene aerogels for ultra-light flexible graphene/texture composites of effective electromagnetic shielding," Carbon, Vol. 93, 151-160, Nov. 2015.
7. Kuang, T., L. Chang, F. Chen, Y. Sheng, D. Fu, and X. Peng, "Facile preparation of lightweight high-strength biodegradable polymer/multi-walled carbon nanotubes nanocomposite foams for electromagnetic interference shielding," Carbon, Vol. 105, 305-313, Aug. 2016.
8. Kocifaj, M., J. Klacka, F. Kundracik, and G. Videen, "Charge-induced electromagnetic resonances in nanoparticles," Annalen der Physik, Vol. 527, No. 11–12, 765-769, Dec. 2015.
9. Sampath, U., Y. Ching, C. Chuah, J. Sabariah, and P. C. Lin, "Fabrication of porous materials from natural/synthetic biopolymers and their composites," Materials, Vol. 9, No. 12, 991, Dec. 2016.
10. Gonzalez, M., M. Crespo, J. Baselga, and J. Pozuelo, "Carbon nanotube scaffolds with controlled porosity as electromagnetic absorbing materials in the gigahertz range," Nanoscale, Vol. 8, No. 20, 10724-10730, 2016.
11. Shen, B., Y. Li, W. Zhai, and W. Zheng, "Compressible graphene-coated polymer foams with ultralow density for adjustable electromagnetic interference (EMI) shielding," ACS Applied Materials and Interfaces, Vol. 8, No. 12, 8050-8057, Mar. 2016.
12. Gargama, H., A. K. Thakur, and S. K. Chaturvedi, "Polyvinylidene fluoride/nanocrystalline iron composite materials for EMI shielding and absorption applications," Journal of Alloys and Compounds, Vol. 654, 209-215, Jan. 2016.
13. Plaquevent, J. C., J. Levillain, F. Guillen, C. Malhiac, and A. C. Gaumon, "Ionic liquids: New targets and media for α-amino acid and peptide chemistry," Chemical Reviews, Vol. 108, No. 12, 5035-5060, Dec. 2008.
14. Lins, L. C., S. Livi, M. Marechal, J. Duchet-Rumeau, and J. F. Gerard, "Structural dependence of cations and anions to building the polar phase of PVDF," European Polymer Journal, Vol. 107, 236-248, Oct. 2018.
15. Panwar, V., B. Kang, J. O. Park, S. Park, and R. M. Mehra, "Study of dielectric properties of styreneacrylonitrile graphite sheets composites in low and high frequency region," European Polymer Journal, Vol. 45, No. 6, 1777-1784, Jun. 2009.
16. Nanni, F., P. Travaglia, and M. Valentini, "Effect of carbon nanofibres dispersion on the microwave absorbing properties of CNF/epoxy composites," Composites Science and Technology, Vol. 69, No. 3–4, 485-490, 2009.
17. Bera, R., S. Paria, S. K. Karan, A. K. Das, A. Maitra, and B. B. Khatua, "NaCl leached sustainable porous flexible Fe3O4 decorated RGO-polyaniline/PVDF composite for durable application against electromagnetic pollution," eXPRESS Polymer Letters, Vol. 11, No. 5, 419-433, May 2017.
18. Rathi, V., V. Panwar, and B. Prasad, "Characterization of PVDF-Gr composite films for electromagnetic interference shielding application," Progress In Electromagnetics Research Letters, Vol. 88, 105-112, 2020.