Load transfer between cross-linked walls of a carbon nanotube

Abstract

Cross links between inner and outer walls of multiwalled carbon nanotubes are believed to increase nanotube modulus and therefore nanotube effectiveness for reinforcing composites. In order to investigate changes in the Young's modulus of individual double-walled nanotubes ͑DWNTs͒ as a function of cross-link density and type, molecular-dynamics simulations are employed to evaluate strain coupling and corresponding load transfer from outer to inner walls. Results show that interwall sp 3 bonds and interstitial carbon atoms can increase load transfer between DWNT walls and that interwall sp 3 bonds are most effective. However, the maximum size of the modulus increase is limited to about 25% for the investigated small-diameter, short DWNTs because the defects decrease the stiffnesses of the nanotube walls.

Bending behavior of double-walled carbon nanotubes with sp3 interwall bonds

“…The sp 3 interwall bonds in the DWCNTs are generated by incrementally moving two close atoms (one in the inner tube and the other one in the outer tube) to the sp 3 bond distance which is about 1.54 Å . 7,14,15 For this study, we focus mainly on the DWCNTs with uniformly distributed sp 3 bonds along the length 16,17 unless otherwise stated. The sp 3 bonds are regularly generated in the DWCNTs and all the sp 3 bonds are uniformly distributed along the length of the CNTs as shown in Fig.…”

“…This may be the main reason why researchers in the literature adopted randomly distributed sp 3 bonds to investigate their effects on the axially loaded MWCNTs. 7,8,14,15,29,30 IV. CONCLUSIONS…”

“…This REBO potential has been widely employed to study the mechanical properties of CNTs. 7,[14][15][16][17][20][21][22] The initial equilibrium configurations of DWCNTs with or without sp 3 bonds are accomplished by the conjugate gradient minimization method. The fifth-order Gear's predictorcorrector integration scheme is adopted with a time step of 1 fs for the integration of equations of motion.…”

“…In sum, it is confirmed from theoretical studies that the load transfer capacity of MWCNTs can be enhanced significantly by the sp 3 interwall coupling, which ultimately make the MWCNTs better reinforcing fibers for composites than SWCNTs. Very recently, Fonseca et al 15 carried out detailed investigation on the load transfer between the linked inner and outer walls in DWCNTs under axial tension. The presence of cross links can increase load transfer between the inner and outer walls of DWCNT.…”

Reparameterization of the REBO-CHO potential for graphene oxide molecular dynamics simulations

“…They are largely used to study the physical and chemical properties of carbon structures [13][14][15][16][17][18][19] . Recent examples of successful studies performed with REBO and AIREBO are the stiffness of graphene with grain boundaries 20 , carbon nanobelts 21 , load transfer behavior in multiwalled carbon nanotubes (MWNTs) with defects connecting their walls [22][23][24] , thermal conductivity of C 13 graphene 25 , and the mechanical properties of graphane 26 .…”