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Understanding Mechanical Response of Elastomeric Graphene Networks.

Ni N, Barg S, Garcia-Tunon E, Macul Perez F, Miranda M, Lu C, Mattevi C, Saiz E - Sci Rep (2015)

Bottom Line: In this work, we constructed elastomeric graphene porous networks with well-defined structures by freeze casting and thermal reduction, and investigated systematically the effect of key microstructural features.A better restoration of the graphitic nature also has a considerable effect.These findings suggest that an improvement in the mechanical properties of porous graphene networks significantly depend on the engineering of the graphene flake that controls the property of the cell walls.

View Article: PubMed Central - PubMed

Affiliation: Centre for Advanced Structural Ceramics, Department of Materials, Imperial College London, London SW7 2AZ, UK.

ABSTRACT
Ultra-light porous networks based on nano-carbon materials (such as graphene or carbon nanotubes) have attracted increasing interest owing to their applications in wide fields from bioengineering to electrochemical devices. However, it is often difficult to translate the properties of nanomaterials to bulk three-dimensional networks with a control of their mechanical properties. In this work, we constructed elastomeric graphene porous networks with well-defined structures by freeze casting and thermal reduction, and investigated systematically the effect of key microstructural features. The porous networks made of large reduced graphene oxide flakes (>20 μm) are superelastic and exhibit high energy absorption, showing much enhanced mechanical properties than those with small flakes (<2 μm). A better restoration of the graphitic nature also has a considerable effect. In comparison, microstructural differences, such as the foam architecture or the cell size have smaller or negligible effect on the mechanical response. The recoverability and energy adsorption depend on density with the latter exhibiting a minimum due to the interplay between wall fracture and friction during deformation. These findings suggest that an improvement in the mechanical properties of porous graphene networks significantly depend on the engineering of the graphene flake that controls the property of the cell walls.

No MeSH data available.


Related in: MedlinePlus

(a) Compressive modulus and (b) yield stress (collapse stress) of the rGO-PNs. (c) and (d) Comparison of the compressive modulus and yield stress with other porous networks. As noted in the main text, the lamellar structure has a cell size of ∼15 μm and the size is approximately doubled by decreasing the cooling rate from 10 K min−1 to 1 K min−1 for the sample labelled as “Lamellar (cell size × 2)”.
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f6: (a) Compressive modulus and (b) yield stress (collapse stress) of the rGO-PNs. (c) and (d) Comparison of the compressive modulus and yield stress with other porous networks. As noted in the main text, the lamellar structure has a cell size of ∼15 μm and the size is approximately doubled by decreasing the cooling rate from 10 K min−1 to 1 K min−1 for the sample labelled as “Lamellar (cell size × 2)”.

Mentions: The compressive modulus and elastic collapse stress (yield stress) of the networks were estimated from the stress-strain curves as shown in Fig. 4a. The behaviour of both properties as a function of sample density and microstructural parameters studied (lamellar vs. foam-like, and increase in pore size in the lamellar network) are shown in Fig. 6a,b. As expected, both increase with increasing sample density; on the other hand, difference in the mechanical properties was small as a result of the variations in architecture (lamellar vs cellular) and pore size, although it appears that the modulus of sample with bigger pores is slightly higher.


Understanding Mechanical Response of Elastomeric Graphene Networks.

Ni N, Barg S, Garcia-Tunon E, Macul Perez F, Miranda M, Lu C, Mattevi C, Saiz E - Sci Rep (2015)

(a) Compressive modulus and (b) yield stress (collapse stress) of the rGO-PNs. (c) and (d) Comparison of the compressive modulus and yield stress with other porous networks. As noted in the main text, the lamellar structure has a cell size of ∼15 μm and the size is approximately doubled by decreasing the cooling rate from 10 K min−1 to 1 K min−1 for the sample labelled as “Lamellar (cell size × 2)”.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4562249&req=5

f6: (a) Compressive modulus and (b) yield stress (collapse stress) of the rGO-PNs. (c) and (d) Comparison of the compressive modulus and yield stress with other porous networks. As noted in the main text, the lamellar structure has a cell size of ∼15 μm and the size is approximately doubled by decreasing the cooling rate from 10 K min−1 to 1 K min−1 for the sample labelled as “Lamellar (cell size × 2)”.
Mentions: The compressive modulus and elastic collapse stress (yield stress) of the networks were estimated from the stress-strain curves as shown in Fig. 4a. The behaviour of both properties as a function of sample density and microstructural parameters studied (lamellar vs. foam-like, and increase in pore size in the lamellar network) are shown in Fig. 6a,b. As expected, both increase with increasing sample density; on the other hand, difference in the mechanical properties was small as a result of the variations in architecture (lamellar vs cellular) and pore size, although it appears that the modulus of sample with bigger pores is slightly higher.

Bottom Line: In this work, we constructed elastomeric graphene porous networks with well-defined structures by freeze casting and thermal reduction, and investigated systematically the effect of key microstructural features.A better restoration of the graphitic nature also has a considerable effect.These findings suggest that an improvement in the mechanical properties of porous graphene networks significantly depend on the engineering of the graphene flake that controls the property of the cell walls.

View Article: PubMed Central - PubMed

Affiliation: Centre for Advanced Structural Ceramics, Department of Materials, Imperial College London, London SW7 2AZ, UK.

ABSTRACT
Ultra-light porous networks based on nano-carbon materials (such as graphene or carbon nanotubes) have attracted increasing interest owing to their applications in wide fields from bioengineering to electrochemical devices. However, it is often difficult to translate the properties of nanomaterials to bulk three-dimensional networks with a control of their mechanical properties. In this work, we constructed elastomeric graphene porous networks with well-defined structures by freeze casting and thermal reduction, and investigated systematically the effect of key microstructural features. The porous networks made of large reduced graphene oxide flakes (>20 μm) are superelastic and exhibit high energy absorption, showing much enhanced mechanical properties than those with small flakes (<2 μm). A better restoration of the graphitic nature also has a considerable effect. In comparison, microstructural differences, such as the foam architecture or the cell size have smaller or negligible effect on the mechanical response. The recoverability and energy adsorption depend on density with the latter exhibiting a minimum due to the interplay between wall fracture and friction during deformation. These findings suggest that an improvement in the mechanical properties of porous graphene networks significantly depend on the engineering of the graphene flake that controls the property of the cell walls.

No MeSH data available.


Related in: MedlinePlus