Scalable van der Waals graphene films for electro‐optical regulation and thermal camouflage

Abstract

Graphene exhibits enormous advantages in mid‐infrared (MIR) regulation because of the active control, precise regulation, and large modulation depth. Such graphene films are prepared via chemical vapor deposition (CVD) or reduction, which cannot realize large‐scale production and limit the applications. Graphene films with van der Waals (vdW) structure enable excellent mechanical and electrical performance for flexible electrodes and electronics and might be a candidate for MIR regulation. However, current techniques for preparing vdW graphene films require binder or solution assistance, resulting in chemical residues and performance degradation. Here, a new strategy for preparing large‐area vdW graphene films by simple mechanical adhesion without any additives was proposed. By selecting the carriers and substrates with proper fracture energies, graphene nanosheets can be transferred from one polymer to another with a layer‐by‐layer structure. The obtained graphene films possess desired thickness and comparable electrical conductivity (92.8 ± 4.6 ohm sq–1) with those by chemical vapor deposition. They are of high compactness even for ions to intercalate reversibly, which exhibit excellent electrochemical activity and electro‐optical regulation capability, effectively suppressing 90% thermal radiation. This strategy can be extended to prepare high‐performance vdW graphene films on various polymer substrates and used for sustainable and smart electro‐optical applications.

Layer-by-Layer Self-Assembly Strategies of Atomically Thin Two-Dimensional Nanomaterials: Principles, Methods, and Functional Applications

“…Li et al proposed a new mechanical adhesion strategy of vdW graphene thin films (vdWGRf) and applied it to MIR regulation, which could effectively suppress 90% of the thermal radiation. 113 They utilized nitrile butadiene rubber (NBR) as a carrier to transfer few-layer graphene onto a porous PTFE substrate via LbL vdW assembly to construct the vdWGRf as the thermal regulating layer. Then they injected 1ethyl-3-methylimidazolium bis(trifluoromethyl sulfonyl) imide (EMIMTFSI) into the porous PTFE substrate as an electrolyte and used copper foil as the counter electrode to produce the electrochemical thermal regulator.…”

“…Compared with traditional CVD or chemical reduction methods, multilayer graphene fabricated by LbL vdW possesses a larger contact area and superior electrical and mechanical properties. Li et al proposed a new mechanical adhesion strategy of vdW graphene thin films (vdWGRf) and applied it to MIR regulation, which could effectively suppress 90% of the thermal radiation . They utilized nitrile butadiene rubber (NBR) as a carrier to transfer few-layer graphene onto a porous PTFE substrate via LbL vdW assembly to construct the vdWGRf as the thermal regulating layer.…”

“…(iii) Schematic diagram of the device structure with voltage on (right, low thermal radiation) and voltage off (left, high thermal radiation). (vi) Demonstration of thermal camouflage of the human body by vdWGRf at 0–4 V continuous voltage . Reproduced with permission from ref .…”

Electrochemical Fine-Tuning of the Chemoresponsiveness of Langmuir–Blodgett Graphene Oxide Films

“…The use of graphene and its derivatives as nanosupports for a variety of electrochemical biointerfaces has experienced a sustainable growth in the past few years. , This can be attributed to their many functional properties that can be exploited to facilitate electrical transduction between biomolecules and the electrode surface. The one-atom-thick planar sheet of carbon atoms densely packed in a honeycomb crystal lattice has remarkable electronic and electrochemical properties that are superior to those found in other nanostructured carbon materials. − …”

Robust superhydrophobic silicone/epoxy functional coating with excellent chemical stability and self-cleaning ability

“…Coating is an important means of addressing functional surface defects in materials. Coatings can not only enhance the resistance to external damage of materials but also give the substrate more diverse, personalized, and functional demands, such as decorative effects like color, texture, and patterns, 1,2 and special requirements like electromagnetic shielding, 3,4 high-temperature resistance, 5 antifreeze, 6 and waterproofing. 7,8 Superhydrophobic coatings have attracted much attention due to their potential applications in solar-power devices, 9 metal corrosion, 10 and communication equipment.…”