Unzipping Carbon Nanotubes at High Impact

Abstract

The way nanostructures behave and mechanically respond to high impact collision is a topic of intrigue. For anisotropic nanostructures, such as carbon nanotubes, this response will be complicated based on the impact geometry. Here we report the result of hypervelocity impact of nanotubes against solid targets and show that impact produces a large number of defects in the nanotubes, as well as rapid atom evaporation, leading to their unzipping along the nanotube axis. Fully atomistic reactive molecular dynamics simulations are used to gain further insights of the pathways and deformation and fracture mechanisms of nanotubes under high energy mechanical impact. Carbon nanotubes have been unzipped into graphene nanoribbons before using chemical treatments but here the instability of nanotubes against defect formation, fracture, and unzipping is revealed purely through mechanical impact.

Fracture of graphene: a review

“…26b). This is consistent with the finding that high impact can unzip carbon nanotubes (Ozden et al 2014). Chew et al (2011) found that the com- Fig.…”

Recent developments in 2D layered inorganic nanomaterials for sensing

“…Jiao et al and Kosynkin et al successfully employed this technique for the first time to prepare graphene nanosheets from MWCNTs 37,38 . Since then, many reports have appeared on the preparation of graphene nanosheets from MWCNTs [39][40][41][42][43] . Besides chemical unzipping, plasma, microwave, electrochemical, microwave and laser assisted unzipping methods have all been used to prepare graphene nanosheets [44][45][46][47] .…”

Chemical-free graphene by unzipping carbon nanotubes using cryo-milling

“…In such kind of complex processes, the fracturing of C-C bonds along a particular direction needs high energy, which can be provided using high strain rate (10 8À10 /s) deformation [20][21][22][23]. In our previous work, we reported a combined experimental and theoretical study of CNTs under high velocity impact [24]. Such experiments give rise to one step chemical-free unzipping due to local concentration of stress at particular location of CNT [24].…”

“…In our previous work, we reported a combined experimental and theoretical study of CNTs under high velocity impact [24]. Such experiments give rise to one step chemical-free unzipping due to local concentration of stress at particular location of CNT [24]. Utilising this understanding, we used a cryo-milling machine designed by us (KC0, Tau Instrument, Bangalore, India) that can deform CNTs with a frequency of 50 Hz and displacement amplitude of 3 mm of the vibrating ball.…”

“…2b. The Raman intensity ratio of D and G bands (I D /I G ), which is related to the density of defects in carbon materials, [24] is used to evaluate the quality of the samples. The original I D /I G value for CNT sample is 0.6, which increases to 0.88 after the cryo-milling.…”