Effective EMI shielding behaviour of thin graphene/PMMA nanolaminates in the THz range

Abstract

The use of graphene in a form of discontinuous flakes in polymer composites limits the full exploitation of the unique properties of graphene, thus requiring high filler loadings for achieving- for example- satisfactory electrical and mechanical properties. Herein centimetre-scale CVD graphene/polymer nanolaminates have been produced by using an iterative ‘lift-off/float-on’ process and have been found to outperform, for the same graphene content, state-of-the-art flake-based graphene polymer composites in terms of mechanical reinforcement and electrical properties. Most importantly these thin laminate materials show a high electromagnetic interference (EMI) shielding effectiveness, reaching 60 dB for a small thickness of 33 μm, and an absolute EMI shielding effectiveness close to 3·105 dB cm2 g−1 which is amongst the highest values for synthetic, non-metallic materials produced to date.

Chemical Vapour Deposition Graphene–PMMA Nanolaminates for Flexible Gas Barrier

“…Recently, some authors have proposed a novel way to incorporate cm-size CVD graphene monolayers into a polymer matrix with a controlled, nanolaminate architecture. The obtained CVD graphene-poly (methyl methacrylate) (PMMA) nanolaminate membranes were found to present enhanced mechanical, electrical and EMI shielding properties, with record values compared to the state-of-the-art [20]. Herein, we demonstrate that the controlled incorporation of CVD graphene into the nanolaminate configuration not only offers improved gas barrier properties compared to the polymer matrix but outperforms traditional discontinuous GRM composites with the same graphene content.…”

“…Nanolaminate membranes were produced by iterative transfer of graphene-PMMA (Gr-PMMA) layers using the 'lift-off/float-on' process combined with the wet depositions described in [20]. Single-layer graphene was grown on copper foil (JX Nippon Mining & Metals, 35 µm thick, 99.95%) in a commercially available CVD reactor (AIXTRON Black Magic Pro, Herzogenrath, Germany).…”

“…After each deposition, the multi-layer was firstly dried at 40 • C under vacuum to remove the excess of water and then post-baked at 150 • C for a few minutes to improve adhesion between subsequent layers. The cycle was repeated until the desired number of Gr-PMMA layers was reached (20). At the end, the Cu substrate was etched away in APS solution to release the freestanding Gr-PMMA nanolaminate, then rinsed with water and finally dried at 40 • C under vacuum to remove the excess of water.…”

Highly Flexible Fabrics/Epoxy Composites with Hybrid Carbon Nanofillers for Absorption-Dominated Electromagnetic Interference Shielding

“…Additionally, many studies have focused on designing flexible films with mechanical durability for EMI-shielding [ 27 , 28 ]. Zeng et al .…”

“…Additionally, many studies have focused on designing flexible films with mechanical durability for EMI-shielding [27,28]. Zeng et al [23] fabricated multi-walled CNT (MWCNT)/water-based polyurethane (WPU) films via a freeze-drying process to obtain EMI-shielding characteristics.…”