Radially Grown Graphene Nanoflakes for Tough and Strong Carbon Fiber Epoxy Composites

Anastasios Karakasidis, Abhijit Ganguly, John Kelly, Preetam Sharma, P Papakonstantinou

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4 Citations (Scopus)
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A long-standing challenge in structural material design is the simultaneous attainment of high strength and toughness, a conflicting requirement rarely met in engineering materials, with important technological applications in aerospace, defense, automobile, and marine industries. Motivated from examples in biological materials, to address this challenge, we demonstrate that strong and damage-tolerant carbon-fiber-reinforced polymers (CFRPs) can be realized via the direct growth of self-assembled radially aligned graphene nanoflakes (GNFs) on carbon fibers (CFs). Here, we report a first-of-its-kind study on the dependence of strength and toughness on the surface morphology of GNFs in CFRPs. The results indicated that fracture toughness was dependent on the density and waviness of the GNFs, whereas the tensile strength was also affected by the periodicity of the coated carbon fiber layers into the laminated structures. Notably, GNFs with reduced waviness and increased number of layers exhibited enhancement in interlaminar fracture toughness for modes I and II by 93.8% and 43.3%, respectively, whereas GNFs with increased waviness led to a marginal increase or preserved tensile strength. The highly interconnected and wavy nature of GNFs facilitated effective load transfer in both in-plane and out-of-plane directions. Moreover, the out-of-plane through-volume conductivity was remarkably enhanced by 527%. The results of this work demonstrated for the first time the unique potential of GNFs, as an excellent nanoreinforcement and electrically conducting interface, for achieving simultaneously strong, tough, and conducting multifunctional CFRP composites.
Original languageEnglish
Pages (from-to)9167-9180
Number of pages14
JournalACS Applied Nano Materials
Issue number9
Early online date26 Aug 2021
Publication statusPublished online - 26 Aug 2021

Bibliographical note

Funding Information:
The authors acknowledge the support from the Air Force Office of Scientific Research (AFOSR) under grant no. FA9550-17-1-0042 and the Department for the Economy (DfE) in Northern Ireland and Ulster University for providing a Ph.D. studentship to A.K.

Publisher Copyright:
© 2021 American Chemical Society


  • graphene nanoflakes
  • Carbon fiber reinforced polymer composites
  • multifunctional composites
  • multifunctional fibers
  • fracture toughness
  • electrical conductivity
  • fracture toughness (mode I)
  • fracture toughness (mode II)
  • tensile strength
  • multifunctional CFRP
  • General Materials Science
  • carbon-fiber-reinforced polymer composites
  • graphene
  • GNFs
  • mode-I and mode-II interlaminar fracture toughness


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