Glass composites reinforced with silicon-doped carbon nanotubes

JX Lu and M Luo and BI Yakobson, CARBON, 128, 231-236 (2018).

DOI: 10.1016/j.carbon.2017.11.074

Glass composite reinforcement by addition of carbon nanotubes (CNTs) is limited due to generally poor load transfer between the matrix and "slippery" reinforcing element. Using computational methods, here we investigate how this load transfer challenge can be overcome by doping the CNT walls with silicon atoms, to create a novel high performance glass composite reinforced with such silicon-doped CNTs (Si-CNTs). It is shown, from first-principles density functional calculations, how silicon dopants in the CNTs should covalently bind with oxygen atoms from the SiO2-glass, resulting in strong interfacial bonding and effective load transfer between the CNTs and the matrix. Molecular dynamics (MD) simulations of this new Si-CNTs reinforced glass composite reveal both similar to 10 times increase of the interfacial traction and up to 60% increase of the Young's modulus. A modified shear-lag model is derived, for predicting the composite's Young's modulus, for finite- length CNTs in matrices, as a function of the interfacial strength, the CNT aspect ratio, and the silicon-dopant concentration. The model can also be extended to other similar short-fiber composites. (c) 2017 Elsevier Ltd. All rights reserved.

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