Advances in Graphene-Polymer Nanocomposite Foams for Electromagnetic Interference Shielding

Abstract

With the continuous advancement of wireless communication technology, the use of electromagnetic radiation has led to issues such as electromagnetic interference and pollution. To address the problem of electromagnetic radiation, there is a growing need for high-performance electromagnetic shielding materials. Graphene, a unique carbon nanomaterial with a two-dimensional structure and exceptional electrical and mechanical properties, offers advantages such as flexibility, light weight, good chemical stability, and high electromagnetic shielding efficiency. Consequently, it has emerged as an ideal filler in electromagnetic shielding composites, garnering significant attention. In order to meet the requirements of high efficiency and low weight for electromagnetic shielding materials, researchers have explored the use of graphene-polymer nanocomposite foams with a cellular structure. This mini-review provides an overview of the common methods used to prepare graphene-polymer nanocomposite foams and highlights the electromagnetic shielding effectiveness of some representative nanocomposite foams. Additionally, the future prospects for the development of graphene-polymer nanocomposite foams as electromagnetic shielding materials are discussed.

Keywords: electromagnetic interference shielding; foam; graphene; polymer composites.

Figure 1

Polymer nanocomposite foams with three different internal structures: (a) coating graphene onto polymeric foams; (b) graphene foam coated with a polymer layer; (c) graphene dispersed in the polymer foam skeleton. Reproduced with permission from [23]. Copyright 2019 Elsevier Ltd.

Figure 2

Fabrication process of polymer-based graphene foams. Reproduced with permission from [24]. Copyright 2013 John Wiley & Sons Inc.

Figure 3

Illustration for preparation of the reduced graphene oxide (RGO)-coated PU sponge. Reproduced with permission from [25]. Copyright 2018 Elsevier Ltd.

Figure 4

Synthesis of graphene foam (GF) coated with poly(methyl methacrylate) (PMMA). Reproduced with permission from [29]. Copyright 2011 Springer Nature.

Figure 5

SEM images of graphene foam/PDMS composites with different porosities: (a) 9.3%; (b) 28.9%; (c) 51.5%; (d) 73.2%; (e) 90.8%. Reproduced with permission from [32]. Copyright 2016 Elsevier Ltd.

Figure 6

Schematic illustration of the supercritical CO₂ foaming process [37].

Figure 7

Fabrication of graphene–PSt foam using compression molding and then the salt-leaching method. Reproduced with permission from [47]. Copyright 2012 Royal Society of Chemistry.

Figure 8

(a) EMI SE_total of graphene–PMMA nanocomposite foams with different volume contents of graphene from 8 to 12 GHz. (b) The values of SE_total, SE_A, and SE_R at 9 GHz with 0 vol%, 0.6 vol%, 0.8 vol%, and 1.8 vol% graphene. Reproduced with permission from [48]. Copyright 2011 American Chemical Society.

Figure 9

The EMI SE_total, SE_A, and SE_R of GPS045 (a) and GPS027 (b) in X-band. Reproduced with permission from [47]. Copyright 2012 Royal Society of Chemistry.

Figure 10

(a) The conductivity of composite foams versus weight percentage of loaded f-G. Inset: plot of log conductivity versus log (p − p_c)/p_c for the composite foams. (b) EMI SE for f-G/PVDF foam composites in X-band. Reproduced with permission from [42]. Copyright 2011 John Wiley & Sons Inc.

Figure 11

SEM images of graphene–PEI nanocomposite foams at different graphene loadings (left); The EMI SSE of graphene–PEI nanocomposite solids and foams at 9.6 GHz (right). Reproduced with permission from [45]. Copyright 2013 American Chemical Society.

Figure 12

Schematic operation for nonsolvent-induced phase separation (NIPS) by soaking the casting film of PAA/rGO in a coagulant bath (a) and the formation process of PAA/rGO composite foams (b). Reproduced with permission from [50]. Copyright 2015 Royal Society of Chemistry.

Figure 13

EMI shielding efficiency of different PU/rUL-GO composite foams at different frequencies. Reproduced with permission from [41]. Copyright 2016 Royal Society of Chemistry.

Figure 14

Overall fabrication process of PUG foams, including dip coating GO sheets onto the PU framework and then hydrothermally reducing them with hydrazine vapor. Reproduced with permission from [53]. Copyright 2016 American Chemical Society.

Figure 15

Schematic of the procedure for fabricating graphene–PDMS foam composites. The scale bars are 500 μm. Reproduced with permission from [31]. Copyright 2013 John Wiley & Sons Inc.

Figure 16

(a) EMI shielding effectiveness of graphene–PDMS foam composites with different electrical conductivities measured in the frequency range of 8–12 GHz (X-band). (b) Comparison of SEtotal, SEA, and SER of graphene–PDMS foam composites with different electrical conductivities at a frequency of 9 GHz. Reproduced with permission from [31]. Copyright 2013 John Wiley & Sons Inc.

Figure 17

Comparison of mean values of SE_T, SE_A, and SE_R over the whole frequency range of (a) GF/PDMS composites with different porosities and (b) GF/CNT/PDMS composites with different CNT contents. Reproduced with permission from [32]. Copyright 2016 Elsevier Ltd.

Figure 18

(a) Schematic procedure for the preparation of GF/PEDOT:PSS composites; EMI SEs of composites with different compositions: (b) SE_A and SE_R and (c) summary of SEs, SSEs, and SSEs normalized by area density as a function of mass ratio of PEDOT:PSS to GF. Reproduced with permission from [56]. Copyright 2017 American Chemical Society.