Wet-Chemical Assembly of 2D Nanomaterials into Lightweight, Microtube-Shaped, and Macroscopic 3D Networks

Abstract

Despite tremendous efforts toward fabrication of three-dimensional macrostructures of two-dimensional (2D) materials, the existing approaches still lack sufficient control over microscopic (morphology, porosity, pore size) and macroscopic (shape, size) properties of the resulting structures. In this work, a facile fabrication method for the wet-chemical assembly of carbon 2D nanomaterials into macroscopic networks of interconnected, hollow microtubes is introduced. As demonstrated for electrochemically exfoliated graphene, graphene oxide, and reduced graphene oxide, the approach allows for the preparation of highly porous (> 99.9%) and lightweight (<2 mg cm −3 ) aeromaterials with tailored porosity and pore size as well as tailorable shape and size. The unique tubelike morphology with high aspect ratio enables ultralow-percolation-threshold graphene composites (0.03 S m −1 , 0.05 vol%) which even outperform most of the carbon nanotube-based composites, as well as highly conductive aeronetworks (8 S m −1 , 4 mg cm −3 ). On top of that, long-term compression cycling of the aeronetworks demonstrates remarkable mechanical stability over 10 000 cycles, even though no chemical cross-linking is employed. The developed strategy could pave the way for fabrication of various macrostructures of 2D nanomaterials with defined shape, size, as well as micro-and nanostructure, crucial for numerous applications such as batteries, supercapacitors, and filters.

Graphene-Based Scaffolds for Regenerative Medicine

“…Such a scaffold was able to direct neuronal growth and align neurons along a defined path to form a network [70]. Another method to fabricate porous structures has been employed by Rasch et al [49]. Starting from tetrapod-shaped ZnO, pressed and annealed in a mold, they were able to synthesize templates with high porosity (50 to 98%).…”

“…Resulting scaffolds show improved mechanical performances and cellular responses. In order to retain porosity, it is crucial to avoid pore saturation through fine Another method to fabricate porous structures has been employed by Rasch et al [49]. Starting from tetrapod-shaped ZnO, pressed and annealed in a mold, they were able to synthesize templates with high porosity (50 to 98%).…”

“…Another method to fabricate porous structures has been employed by Rasch et al [ 49 ]. Starting from tetrapod-shaped ZnO, pressed and annealed in a mold, they were able to synthesize templates with high porosity (50 to 98%).…”

“… Examples of two-dimensional and three-dimensional scaffolds. ( a ) CVD graphene on Si/SiO 2 chip and AFM images of graphene transferred on different polymeric substrates [ 45 ]; ( b ) graphene transferred on nanopatterned substrate and AFM image [ 46 ]; ( c ) PLLA-RGO film obtained as reported in [ 47 ]; ( d ) graphite oxide paper [ 48 ]; ( e ) GO foams and SEM images [ 49 ]; ( f ) PLLA-RGO electrospun fibers obtained as reported in [ 50 ]; ( g ) peptide–GO hybrid hydrogels and TEM images [ 51 ]. …”

Ultra-Sensitive Piezo-Resistive Sensors Constructed with Reduced Graphene Oxide/Polyolefin Elastomer (RGO/POE) Nanofiber Aerogels

“…Nanofiber aerogels, which were obtained by removing the solvent component from the nanofiber suspension in a supercritical state, possess the highest porosity (>80%) among the fiber assemblies. The randomly distributed POE nanofibers with a high length-diameter ratio would lead to hierarchical self-entanglement and would help form a three-dimensional nanofiber-based network [23,24]. Moreover, the ultra-high specific surface area (>500 m 2 /g) of the nanofiber aerogel provides the structural basis for the interconnection of conductive components under compression.…”