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Large-deformation and high-strength amorphous porous carbon nanospheres.

Yang W, Mao S, Yang J, Shang T, Song H, Mabon J, Swiech W, Vance JR, Yue Z, Dillon SJ, Xu H, Xu B - Sci Rep (2016)

Bottom Line: In contrast, amorphous carbon is known to be very brittle and can sustain little compressive deformation.In situ compression experiments on individual nanospheres show that the amorphous carbon nanospheres with an optimized structure can sustain beyond 50% compressive strain.Both experiments and finite element analyses reveal that the buckling deformation of the outer spherical shell dominates the improvement of strength while the collapse of inner nanoscale pores driven by twisting, rotation, buckling and bending of pore walls contributes to the large deformation.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA 22904, USA.

ABSTRACT
Carbon is one of the most important materials extensively used in industry and our daily life. Crystalline carbon materials such as carbon nanotubes and graphene possess ultrahigh strength and toughness. In contrast, amorphous carbon is known to be very brittle and can sustain little compressive deformation. Inspired by biological shells and honeycomb-like cellular structures in nature, we introduce a class of hybrid structural designs and demonstrate that amorphous porous carbon nanospheres with a thin outer shell can simultaneously achieve high strength and sustain large deformation. The amorphous carbon nanospheres were synthesized via a low-cost, scalable and structure-controllable ultrasonic spray pyrolysis approach using energetic carbon precursors. In situ compression experiments on individual nanospheres show that the amorphous carbon nanospheres with an optimized structure can sustain beyond 50% compressive strain. Both experiments and finite element analyses reveal that the buckling deformation of the outer spherical shell dominates the improvement of strength while the collapse of inner nanoscale pores driven by twisting, rotation, buckling and bending of pore walls contributes to the large deformation.

No MeSH data available.


Related in: MedlinePlus

Carbon nanospheres with different pore structures.(a–c) TEM images and (d–f) SEM images of carbon spheres studied in this work, and their corresponding schematic illustrations (g–i).
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f1: Carbon nanospheres with different pore structures.(a–c) TEM images and (d–f) SEM images of carbon spheres studied in this work, and their corresponding schematic illustrations (g–i).

Mentions: Figure 1 shows the TEM and SEM images of synthesized porous spheres with different interior pore sizes and their corresponding schematic illustrations. Carbon nanospheres containing macropores (100 ~ 200 nm) separated by thin carbon sheets can be obtained from pyrolyzing potassium propiolates while carbon nanospheres with mesopores (10 ~ 20 nm) can be obtained using lithium propiolates as precursors (Supplementary Figure S2). The thickness of outer shell in macroporous and mesoporous carbon nanospheres is 15 ~ 30 nm and 4 ~ 10 nm, respectively. Moreover, hollow carbon nanospheres were generated using a mixture of lithium, sodium, and potassium propiolates as precursors. The porous carbon spheres synthesized in this approach are amorphous even after heat treatment at 800 °C for 12 hours (Supplementary Figure S3). Raman analysis reveals that the carbon spheres prepared in the above described method consist of both sp2 and sp3 hybridized carbon bonds. And there is no dramatic variance of graphitic and aliphatic carbons between different carbon nanospheres as the ID/IG ratios of carbon nanospheres with different structures are very close even after heat treatment (Supplementary Figure S3). The density of carbon nanospheres with macroporous and mesoporous pores were 0.21 and 0.26 g/cm3 respectively. The density of hollow carbon nanospheres was measured to be 0.47 g/cm3. Therefore, the density of porous carbon nanospheres obtained in this approach is approximately one order of magnitude lower than that of solid amorphous carbon (2.0 ~ 2.4 g/cm3)2021.


Large-deformation and high-strength amorphous porous carbon nanospheres.

Yang W, Mao S, Yang J, Shang T, Song H, Mabon J, Swiech W, Vance JR, Yue Z, Dillon SJ, Xu H, Xu B - Sci Rep (2016)

Carbon nanospheres with different pore structures.(a–c) TEM images and (d–f) SEM images of carbon spheres studied in this work, and their corresponding schematic illustrations (g–i).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4829827&req=5

f1: Carbon nanospheres with different pore structures.(a–c) TEM images and (d–f) SEM images of carbon spheres studied in this work, and their corresponding schematic illustrations (g–i).
Mentions: Figure 1 shows the TEM and SEM images of synthesized porous spheres with different interior pore sizes and their corresponding schematic illustrations. Carbon nanospheres containing macropores (100 ~ 200 nm) separated by thin carbon sheets can be obtained from pyrolyzing potassium propiolates while carbon nanospheres with mesopores (10 ~ 20 nm) can be obtained using lithium propiolates as precursors (Supplementary Figure S2). The thickness of outer shell in macroporous and mesoporous carbon nanospheres is 15 ~ 30 nm and 4 ~ 10 nm, respectively. Moreover, hollow carbon nanospheres were generated using a mixture of lithium, sodium, and potassium propiolates as precursors. The porous carbon spheres synthesized in this approach are amorphous even after heat treatment at 800 °C for 12 hours (Supplementary Figure S3). Raman analysis reveals that the carbon spheres prepared in the above described method consist of both sp2 and sp3 hybridized carbon bonds. And there is no dramatic variance of graphitic and aliphatic carbons between different carbon nanospheres as the ID/IG ratios of carbon nanospheres with different structures are very close even after heat treatment (Supplementary Figure S3). The density of carbon nanospheres with macroporous and mesoporous pores were 0.21 and 0.26 g/cm3 respectively. The density of hollow carbon nanospheres was measured to be 0.47 g/cm3. Therefore, the density of porous carbon nanospheres obtained in this approach is approximately one order of magnitude lower than that of solid amorphous carbon (2.0 ~ 2.4 g/cm3)2021.

Bottom Line: In contrast, amorphous carbon is known to be very brittle and can sustain little compressive deformation.In situ compression experiments on individual nanospheres show that the amorphous carbon nanospheres with an optimized structure can sustain beyond 50% compressive strain.Both experiments and finite element analyses reveal that the buckling deformation of the outer spherical shell dominates the improvement of strength while the collapse of inner nanoscale pores driven by twisting, rotation, buckling and bending of pore walls contributes to the large deformation.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA 22904, USA.

ABSTRACT
Carbon is one of the most important materials extensively used in industry and our daily life. Crystalline carbon materials such as carbon nanotubes and graphene possess ultrahigh strength and toughness. In contrast, amorphous carbon is known to be very brittle and can sustain little compressive deformation. Inspired by biological shells and honeycomb-like cellular structures in nature, we introduce a class of hybrid structural designs and demonstrate that amorphous porous carbon nanospheres with a thin outer shell can simultaneously achieve high strength and sustain large deformation. The amorphous carbon nanospheres were synthesized via a low-cost, scalable and structure-controllable ultrasonic spray pyrolysis approach using energetic carbon precursors. In situ compression experiments on individual nanospheres show that the amorphous carbon nanospheres with an optimized structure can sustain beyond 50% compressive strain. Both experiments and finite element analyses reveal that the buckling deformation of the outer spherical shell dominates the improvement of strength while the collapse of inner nanoscale pores driven by twisting, rotation, buckling and bending of pore walls contributes to the large deformation.

No MeSH data available.


Related in: MedlinePlus