Construction of a carbon fiber based layer-by-layer (LbL) assembly – a smart approach towards effective EMI shielding† Yudhajit Bhattacharjee, Viraj Bhingardive, Sourav Biswas and Suryasarathi Bose * Construction of ultrathin multilayer polymer nanocomposite films by precise layer-by-layer (LbL) architectural assembly with tailor-made properties has been achieved here to block incoming EM radiation. To accomplish this, Mn (manganese)–ferrite nanoparticles were synthesized and incorporated in a thermoplastic matrix (PVDF, poly- vinylidene fluoride) along with conductive MWNTs (PNTMn–Fe) by a facile solution blending process. These nanocomposite films were used as outer layers of the LbL assembly. In order to scavenge the transmitted radiation through PNTMn–Fe layers, PVDF films sand- wiched with a Ni (nickel)-deposited woven carbon fiber (CF) mat (PCF@NiP), designed using a facile electroless deposition technique. These layers were used as inner layers of the LbL assembly. The different layers were then stacked and hot pressed into a composite structure. This ultrathin (0.60 mm) multilayer architecture showed an extraordinary (52 dB at 18 GHz) shielding effectiveness and thereby promises a smart approach to accomplish a lightweight, high perfor- mance, EMI shielding material. Introduction Enormous use of electronic devices, communication systems and other instruments are creating problems for the device itself and nearby circuitry due to electromagnetic (EM) inter- ference among devices which degrade their performance. One of the effective ways to tackle with this problem is either shielding or arresting these EM waves. 1–5 Metals are effective in this context and widely applied to block the incoming EM radiation. However, due to their associated limitations, such as expense, heaviness and susceptibility to corrosion, light-weight polymeric composites with effective electromagnetic interfer- ence (EMI) shielding performance are becoming potential substitutes in this electronic world, which is rapidly switching to miniaturization. 6–11 Today, carbon derivatives like carbon ber (CF), carbon nanotubes (single walled, multi-walled), and graphene possessing high electrical conductivity, a high aspect ratio and better mechanical properties, are claimed to be deserving candidates for fabrication of high performance composites. 12–18 The interface between bre and the matrix plays a pivotal part in composite properties. 19–21 Due to their outstanding electrical conductivity and high aspect ratio, multi wall carbon nanotubes (MWNTs) are the ideal nanollers in composites which have been extensively used to give an understanding towards research on hybrid composites. 20,22–25 Recently, interest is mounting in the development of hybrid (or multi-scale or hierarchical) materials, in which nanoscale reinforcement is utilized in conjunction with traditional micro- scale carbon bers. 23,26 It is well known that carbon bers are extensively used in applications due to their high strength, high aspect ratio and better electrical conductivity. 27–29 Hence, in order take advantage of these properties woven carbon bers (CF) mats are utilized in the present work. EM radiation consists of two vector components (electrical and magnetic) which are perpendicular to each other, so to circumvent such consequences, materials that contain both electric and magnetic dipoles are required. So, designing new hybrid nanomaterials is the burgeoning research interest. In recent past, many researchers have tried to incorporate neat carbon bers, as well as electrodeposited carbon bers for shielding applications. 19,30,31 There are various methods available to deposit metal particles onto carbon bers viz. electrochemical deposi- tion, electro less deposition etc. 19,30,32 However, since electroless deposition is simple, efficient, and inexpensive and does not require external sources, 33–35 we adopted this technique in the present investigation. Furthermore, we have synthesized Mn– ferrite nanoparticles which show good magnetic properties – a key requisite for effective EM absorption. In this article we have designed and fabricated a layer by layer (LbL) assembly of so nanocomposites consisting of PVDF, electroless deposited carbon ber mat (PCF@NiP) and a thin lm of PNTMn–Fe. Here, we believe that the PCF@NiP along with intercalated thin lm of PNTMn–Fe, composite will work in tandem and play a vital role in attenuating EM radiation. Department of Materials Engineering, Indian Institute of Science, Bangalore – 560012, India. E-mail: sbose@materials.iisc.ernet.in † Electronic supplementary information (ESI) available. See DOI: 10.1039/c6ra24238c Cite this: RSC Adv. , 2016, 6, 112614 Received 29th September 2016 Accepted 17th November 2016 DOI: 10.1039/c6ra24238c www.rsc.org/advances 112614 | RSC Adv. , 2016, 6, 112614–112619 This journal is © The Royal Society of Chemistry 2016 RSC Advances COMMUNICATION Published on 18 November 2016. Downloaded by Indian Institute of Science on 28/11/2016 19:59:32. View Article Online View Journal | View Issue