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.

The synthesis of large, defect-free two-dimensional materials (2DMs) such as graphene is a major challenge toward industrial applications. Chemical vapor deposition (CVD) on liquid metal catalysts (LMCats) is a recently developed process for the fast synthesis of high-quality single crystals of 2DMs. However, up to now, the lack of in situ techniques enabling direct feedback on the growth has limited our understanding of the process dynamics and primarily led to empirical growth recipes. Thus, an in situ multiscale monitoring of the 2DMs structure, coupled with a real-time control of the growth parameters, is necessary for efficient synthesis. Here we report real-time monitoring of graphene growth on liquid copper (at 1370 K under atmospheric pressure CVD conditions) via four complementary in situ methods: synchrotron X-ray diffraction and reflectivity, Raman spectroscopy, and radiation-mode optical microscopy. This has allowed us to control graphene growth parameters such as shape, dispersion, and the hexagonal supra-organization with very high accuracy. Furthermore, the switch from continuous polycrystalline film to the growth of millimeter-sized defect-free single crystals could also be accomplished. The presented results have far-reaching consequences for studying and tailoring 2D material formation processes on LMCats under CVD growth conditions. Finally, the experimental observations are supported by multiscale modeling that has thrown light into the underlying mechanisms of graphene growth.

In this review we highlight the recent progress in 2DM growth on LMCat, which in combination with in situ characterization presents a viable and large-scale sustainable direction that has the prospect of achieving defect-free 2D materials.

Graphene is susceptible to morphological instabilities such as wrinkles and folds, which result from the imposition of thermo-mechanical stresses upon cooling from high temperatures and/ or under biaxial loading. A particular pattern encountered in CVD graphene is that of mosaic formation. Although it is understood that this pattern results from the severe biaxial compression upon cooling from high temperatures, it has not been possible to create such a complex pattern at room temperature by mechanical loading. Herein, we have managed by means of lateral wrinkling induced by tension and Euler buckling resulting from uniaxial compression upon unloading, to create such patterns in exfoliated graphene. We also show that these patterns can be used as channels for trapping or administering fluids at interstitial space between graphene and its support. This opens a whole dearth of new applications in the area of nano-fluidics but also in photo-electronics and sensor technologies.