Highly conductive and flexible polymer composites with improved mechanical and electromagnetic interference shielding performances

Abstract

New flexible and conductive materials (FCMs) comprising a quartz fiber cloth (QFC) reinforced multi-walled carbon nanotubes (MWCNTs)-carbon aerogel (QMCA) and poly(dimethylsiloxane) (PDMS) have been successfully prepared. The QMCA-PDMS composite with a very low loading of MWCNTs (∼1.6 wt%) demonstrates enhanced performance in tensile strength (129.6 MPa), modulus (3.41 GPa) and electromagnetic interference (EMI) shielding efficiency (SE) (∼16 dB in X-band (8.2-12.4 GHz) region). Compared to the QC (where MWCNTs were simply deposited on the QFCs without forming aerogel networks) based PDMS composite, a ∼120%, 330% and 178% increase of tensile strength, modulus, and EMI SE was obtained, respectively. Moreover, the EMI SE of the QMCA-PDMS composite can further reach 20 dB (a SE level needed for commercial applications) with only 2 wt% MWCNTs. Furthermore, the conductivity of the QMCA-PDMS laminate can reach 1.67 S cm(-1) even with very low MWCNTs (1.6 wt%), which still remains constant even after 5000 times bending and exhibits an increase of ∼170% than that of MWCNT-carbon aerogel (MCA)-PDMS at 20% strain. Such intriguing performances are mainly attributed to their unique networks in QMCA-PDMS composites. In addition, these features can also protect electronics against harm from external forces and EMI, giving the brand-new FCMs huge potential in next-generation devices, like E-skin, robot joints and so on.

Carbon nano-ink coated open cell polyurethane foam with micro-architectured multilayer skeleton for damping applications

“…These particular subset of foams exhibit increased strength [1][2][3], electrical conductivities [2,4,5], and damping [6][7][8][9] over their traditional counterparts. While the applications of polymer nanocomposite foams like flexible sensors [10] and electromagnetic shielding [2,11] have been widely reported, very few studies have however focused on the damping applications for noise and vibration control. In recent years experimental studies and numerical modelling have been carried out to describe the widely reported interfacial sliding mechanism in nanocomposites for damping treatments.…”

Electromagnetic interference shielding properties and mechanisms of chemically reduced graphene aerogels

“…In addition to high EMI shielding performance, light weight is an additional important technical requirement for potential applications especially in the areas of automobile and aerospace. Searching for the library of EMI shielding materials, conductive polymer composites foams [4,5], carbon foams [6] and conductive aerogels [7] emerged as potential EMI shielding materials due to their advantages in effective weight reduction, chemical stability and design flexibility. Electrical conductive fillers, such as carbon nanofibers (CNFs) [8,9], carbon nanotubes (CNTs) [10,11] and graphene sheets [12][13][14], were commonly used to form a conducting network with desirable electrical conductivity within the intrinsically insulating polymer foam matrix, a crucial requirement for effective EMI shielding properties.…”

High porosity scaffold composites of graphene and carbon nanotubes as microwave absorbing materials

“…Samples containing higher CNTs are more reflective as a consequence of a higher electrical conductivity. [43][44][45] Therefore, the sample that only contains graphene presents the highest P A which decreases as the CNT content is increased due to the higher amount of reflected power. The electromagnetic shielding mechanism was investigated through a shielding efficiency (SE) analysis (eqn (2), (3) and (4)).…”