A Plesiohedral Cellular Network of Graphene Bubbles for Ultralight, Strong, and Superelastic Materials

Abstract

Advanced materials with low density and high strength impose transformative impacts in the construction, aerospace, and automobile industries. These materials can be realized by assembling well-designed modular building units (BUs) into interconnected structures. This study uses a hierarchical design strategy to demonstrate a new class of carbon-based, ultralight, strong, and even superelastic closed-cellular network structures. Here, the BUs are prepared by a multiscale design approach starting from the controlled synthesis of functionalized graphene oxide nanosheets at the molecular- and nanoscale, leading to the microfluidic fabrication of spherical solid-shelled bubbles at the microscale. Then, bubbles are strategically assembled into centimeter-scale 3D structures. Subsequently, these structures are transformed into self-interconnected and structurally reinforced closed-cellular network structures with plesiohedral cellular units through post-treatment, resulting in the generation of 3D graphene lattices with rhombic dodecahedral honeycomb structure at the centimeter-scale. The 3D graphene suprastructure concurrently exhibits the Young's modulus above 300 kPa while retaining a light density of 7.7 mg cm and sustaining the elasticity against up to 87% of the compressive strain benefiting from efficient stress dissipation through the complete space-filling closed-cellular network. The method of fabricating the 3D graphene closed-cellular structure opens a new pathway for designing lightweight, strong, and superelastic materials.

Structurally Controlled Cellular Architectures for High‐Performance Ultra‐Lightweight Materials

“…Ashby plots (i.e., Young's modulus vs density and relative Youngs' modulus vs relative density) for different open‐stochastic, open‐periodic, closed‐stochastic, and closed‐periodic cellular materials. [10,12,18,23,34b,d–f,35c,36b,40,41b,42b,c,43c,45a,49,50c,54a,59,60b,c,67c,68a–c,71,72] The symbol colors correspond to the constituent materials (i.e., metallic‐, ceramic‐, carbon‐, and polymeric‐based). Open, open + cross, and closed symbols are assigned to open‐stochastic, open‐periodic (lattices), and closed‐cellular structures, respectively.…”

“…To hurdle this challenge, we recently reported a new class of graphene‐based closed‐cellular structures with uniform and plesiohedra‐shaped shells, as shown in Figure a . The use of handshaken emulsified GO solutions leads to the generation of nonuniform porous cellular networks.…”

“…i) Photographs showing the superelasticity of the 3D RDH structure. a–i) Reproduced with permission . Copyright 2018, Wiley‐VCH.…”

Graphene‐Based Ultralight Compartmentalized Isotropic Foams with an Extremely Low Thermal Conductivity of 5.75 mW m−1 K−1

“…In particular, the importance of thermal insulating materials has emerged not only for temperature-sensitive micro-devices, such as including microelectromechanical systems, [1] thermoelectric devices, [2] and infrared detecting sensors, [3] but also for small to accommodate gas convection. [13] Additionally, radiative heat transfer is known to marginally affect the overall thermal conductivity (<2 mW m −1 K −1 ), particularly for ultralight (<10 mg cm −3 ) structured insulating materials with thicknesses less than the centimeter scale. [11,14,15] Therefore, to realize highperformance thermally insulating materials in a pre-defined way, it is necessary to minimize the solid-state conduction that occurs along the interconnected paths in a porous structure as well as the gas conduction through internal pores in porously structured foams.…”

Controlled open-cell two-dimensional liquid foam generation for micro- and nanoscale patterning of materials

“…This physical characteristic allows the liquid parts of material inks to be shaped freely with physicochemical forces, benefiting evaporative bottom-up assembly of target materials in inks into desired patterns; typically, this process is called liquid-mediated patterning (LP). Historically, early strategic tools for the liquid shaping, such as oriental brushes and printing presses have significantly affected civilization 2,3 , and recent advancements in microfluidic and nanofluidic for spatiotemporal manipulation of microscale and nanoscale fluids 4 have substantially enriched studies on functional materials 5–8 . In particular, natural liquid foam systems observed in soap, beer, and even embryogenesis 9 can be advantageous compared to reported microfluidic and nanofluidic LP (MNLP) techniques in comprehensive perspectives of cost, dimensions, controllability, and scalability.…”