Vertically Aligned Carbon Nanotube@Graphene Paper/Polydimethylsilane Composites for Electromagnetic Interference Shielding and Flexible Joule Heating

Abstract

High-performance electromagnetic interference (EMI) shielding and thermal management materials with ultraflexibility, high strength, outstanding stability under mechanical deformation, and low cost are urgently demanded for modern integrated electronic and telecommunication systems. However, the creation and application of such desirable materials is still a potent challenge. Herein, we develop such a high-performance multifunctional multilayer composite, known as vertically aligned carbon nanotube@graphene paper/polydimethylsilane (VACNT@GP/PDMS), which involves the in situ growth of VACNTs onto GPs, vertical stacking of VACNT@GP layers, and infiltration of PDMS. The EMI shielding and mechanical properties of multilayer composites can be dramatically increased by increasing the number of VACNT@GP layers. Benefiting from the conduction loss in highly conductive GPs and polarization of huge VACNT–PDMS–VACNT microcapacitor networks, the multilayer composite with four VACNT@GP layers exhibits a superior EMI SE of 106.7 dB over a broad bandwidth of 32 GHz, covering the entire X-, Ku-, K-, and Ka-bands, which far suppresses the values of most of the reported EMI shielding materials. Moreover, the multilayer composites show excellent thermal management performance such as a high Joule-heating temperature at low supplied voltages, rapid response time, and sufficient heating stability. In addition, remarkable flexibility, high tensile strength (up to 13.4 MPa), and super stability under mechanical deformation (nearly no EMI SE degradation after repeatedly bending 10,000 times) are also discovered. These excellent comprehensive properties, along with the ease of low-cost mass production, pave the way for the practical applications of multilayer VACNT@GP/PDMS composites in EMI shielding and thermal management.

Conducting Interface for Efficient Growth of Vertically Aligned Carbon Nanotubes: Towards Nano-Engineered Carbon Composite

“…A well-prepared GP always presents a low defect level and good crystalline structure with crystallite size in the range of µm-scale and stacking order of graphene flakes similar to that of HOPG. As therein presented [49], the structural properties of the used GP have been sufficient to support the deposition of a dense network of Fe catalyst nanoparticles and the simultaneous growth of VACNT. Figure 22 presents SEM images of 20 µm height VACNT grown on two sides of a single layer of GP.…”

“…Substrates of different nature and morphology are evidenced as suitable for the growth of VACNT due to easy-to-analyze or easy-to-industrialize properties. Various substrates have been used for the growth of VACNT, such as silicon wafers [9,24,31,34,35], quartz [36], aluminium foil [13,37,38], piezoelectric aluminium nitride film [39], stainless steel [40], titanium wire [41], magnesia and magnesium aluminate [42], as well as carbon fiber cloth [36,[43][44][45] or paper [46,47], graphite [5,48], graphene paper [49] or oxide [50], reticulated carbon foam [51], and many others [21,52]. Among all, commercial fibrous carbon 3D substrates (CF tow, cloth, felt, paper, or other woven or non-woven fabrics) are advantageous since they possess exceptionally high mechanical strength and well-defined anisotropic thermal and electrical properties [53].…”

“…In this subsection, the review summarizes different approaches reported for the use of un-/modified carbon substrate or the same with predeposited DBL (via CVD or PVD) for the growth of VACNT. Even though few studies have examined the growth of VACNT on a carbonaceous substrate without the use of interface [5,32,48,49], promoted growth of tunable VACNT on CF is today achievable through the use of suitable DBL [4,36,43,44,47,[95][96][97][98][99][100]. The cited and other references therein show that covering a CF substrate with an intermediate DBL can radically improve the growth of VACNT and prevent the possible degradation of the fiber structural properties.…”

“…The achieved strong and direct covalent bond of the CNT with the graphite substrate is defined to support the structural integrity during mechanical bending. Very recently, He et al ( 2022) [49] have presented high-performance advanced EMI shielding and thermal management multifunctional multilayer composite based on the VACNT-graphene paper (GP)/polydimethylsilane (PDMS). The authors detail the application performance of the cited composite due to its mechanical and conductivity properties and multi-layer structure (details given in Table 7).…”

“…Whereas little is given for the CVD growth process of VACNT onto spruce GP and the structural characteristics of the GP substrate or the achieved VACNT (summarized in Table 7). GP is generally synthesized from a graphene oxide film, derived via the Hummer method, and additional film Very recently, He et al (2022) [49] have presented high-performance advanced EMI shielding and thermal management multifunctional multilayer composite based on the VACNT-graphene paper (GP)/polydimethylsilane (PDMS). The authors detail the applica-tion performance of the cited composite due to its mechanical and conductivity properties and multi-layer structure (details given in Table 7).…”