Fluid dynamic lateral slicing of high tensile strength carbon nanotubes

ABSTRACT Lateral slicing of micron length carbon nanotubes (CNTs) is effective on laser irradiation of the materials suspended within dynamic liquid thin films in a microfluidic vortex

fluidic device (VFD). The method produces sliced CNTs with minimal defects in the absence of any chemical stabilizers, having broad length distributions centred at _ca_ 190, 160 nm and 171 

nm for single, double and multi walled CNTs respectively, as established using atomic force microscopy and supported by small angle neutron scattering solution data. Molecular dynamics

simulations on a bent single walled carbon nanotube (SWCNT) with a radius of curvature of order 10 nm results in tearing across the tube upon heating, highlighting the role of shear forces

which bend the tube forming strained bonds which are ruptured by the laser irradiation. CNT slicing occurs with the VFD operating in both the confined mode for a finite volume of liquid and

continuous flow for scalability purposes. SIMILAR CONTENT BEING VIEWED BY OTHERS FABRICATION OF ANGSTROM-SCALE TWO-DIMENSIONAL CHANNELS FOR MASS TRANSPORT Article 27 November 2023 THE

HIGH-THROUGHPUT ATOMIZATION OF POLYMER SOLUTIONS FOR FIBER SYNTHESIS IN A SINGLE STEP AIDED WITH CORONA IONIZERS Article Open access 03 August 2023 INVESTIGATING THE ATOMIC BEHAVIOR OF

CARBON NANOTUBES AS NANOPUMPS Article Open access 23 October 2023 INTRODUCTION The processing of cylindrical carbon nanotubes (CNTs) for exploiting their exceptional thermal, mechanical, and

electrical properties1 poses a number of challenges. This includes overcoming a high degree of bundling and aggregation arising from their high aspect ratio and strong inter-tube van der

Waals interactions. The CNTs are microns to millimetres in length, and may have single or multiple layers, described as single walled (SWCNTs), double walled (DWCNTs) or multi walled

(MWCNTs). They have low density, and high stiffness and axial strength2 with an exceptionally high Young’s modulus, 1.0 to 1.28 TPa3,4,5. CNTs are produced using a number of techniques,

including arc-discharge, laser ablation and chemical vapour deposition (CVD)6,7,8, typically affording arrays of nanotubes in various lengths. However, the availability of shorter lengths

without compromising quality is important for many applications, for example, in incorporating them into lipid bilayers for molecular sensing2, and for enhancing the efficiency of electronic

devices3,4,9, for solar cell applications10 and for chirality separation11,12,13. There has thus been considerable work directed at shortening CNTs towards sub-micron lengths, but this has

proved challenging, currently requiring the use of high-energy sonication, lengthy processing times and the use of toxic chemicals14,15,16,17,18,19,20,21,22,23,24. Moreover, such conditions

can chemically alter the surface of the CNTs with consequential change in their properties, thereby limiting their applications. Controlling the shortening of CNTs requires the use of a

suitable processing medium in overcoming their tendency to aggregate, with some common solvents such as N-methyl-2-pyrollidone (NMP) and N,N-dimethylformamide (DMF) being effective

dispersants for such purpose. The colloidal stability of individual CNTs usually requires polymer wrapping agents25 and surfactants26, and covalent end and/or sidewall

functionalization27,28. We have established a new means to achieve shortening of CNTs that avoids many of these problems. Despite their high tensile strength, CNTs can be laterally sliced in

solution by applying intense shear within dynamic thin films in a vortex fluidic device (VFD) while irradiating at 1064 nm using a pulsed Q-switch Nd:YAG laser (Fig. 1a). The VFD

microfluidic platform generates controllable mechanoenergy within the liquid medium, as thin films around the internal walls of a rapidly rotating tube, which for practical purposes was a 20

 mm diameter (ID 16.000 ± 0.013 mm) borosilicate nuclear magnetic resonance (NMR) glass tube. In general, the optimal performance of the VFD occurs at high rotational speeds (2000 rpm to

9000 rpm) and inclination angles, θ > 0°, with a 45° tilt angle corresponding to the maximum cross vector of centrifugal force and gravity, being the optimum setting for a diverse number

of applications of the device29,30,31,32,33,34,35. RESULTS AND DISCUSSION Both the confined and continuous modes of operation of the VFD are effective in slicing of the CNTs. In the confined

mode a finite volume of liquid is wholly contained within the tube during processing while ensuring that a vortex is maintained to the bottom of the tube for moderate rotational speeds, and

without any liquid exiting at the top of the tube. This minimises the formation of different shear regimes. In this mode, Stewartson/Ekman layers prevail in the resulting dynamic thin

films, which arise from the liquid accelerating up the tube, with gravitational force acting against them30. In the continuous flow mode of operation of the VFD, jet feeds deliver one or

more solutions (normally) to the bottom of the tube where there is intense micromixing, with instability of the liquid boundary layer in the hemispherical sphere at the bottom of the tube.

The viscous drag as the liquid whirls up the tube creates shear, in addition to that from the Stewartson/Ekman layers. These unique fluidic properties of the VFD have led to a number of

applications including control of chemical reactivity and selectivity in organic synthesis29,30, exfoliating graphene and boron nitride31, protein folding32, fabricating toroidal arrays of

SWCNTs33, forming mesoporous silica at room temperature with control of pore size and wall thickness34, and probing the structure of self organised processes35,36. The volume of liquid for

confined mode studies was set at 1 mL with the speed and tilt angle varied to establish the lowest time for two liquids to homogenously mix. This was important to optimise exposure of the

CNTs in the solution to the 8 mm diameter laser beam used in the ‘slicing’ experiments, as well as providing the maximum shear for debundling of the tubes. The minimum time taken for a

homogenous mixture of water and NMP (1:1 ratio) to uniformly mix (visually estimated for solutions containing a dye, in the range 2000 to 9000 rpm, was for a rotational speed of 7500 rpm

(Fig.1) for θ 45°. The choice of a 1:1 ratio of water and NMP was based on overcoming the low mixing time for NMP, in which the CNTs are readily dispersed, versus the fast mixing times in

water, in which there is little dispersion of CNTs. These VFD parameters (θ 45o, 7500 rpm rotational speed) also correspond to the optimal processing parameters (_vide infra_). Energy

absorption from the pulsed laser source was essential to laterally slice the CNTs. The laser produces 1064 nm pulses of 5 ns duration and operates at a repetition rate of 10 Hz. In the

confined mode, the optimised irradiation conditions were found to be a laser power of 260 mJ/pulse for, 30 minutes of processing. This was established by determining CNT length distributions

using AFM on isolated samples (Supplementary Fig. S5). At high laser powers, ≥400 mJ, only small amounts of sliced nanotubes were evident, along with bundled and aggregated long nanotubes.

Here the extra heat provided by the laser pulse disturbs the fluid flow, with a clear band which is presumably largely devoid of CNTs at the point of laser irradiation. Decreasing the laser

power to <200 mJ for 30 minutes was ineffective in slicing the CNTs and no clear band was observed at the irradiation site. (Supplementary Fig. S5). The optimal VFD processing parameters

(inclination angle θ and rotational speed) were determined following a number of control experiments. For rotational speeds below 6000 rpm, the as-received aggregated bundles of CNTs

(SWCNTs, DWCNTs and MWCNTs) remained unaffected in both the presence and absence of laser irradiation. At 6000 rpm and 45° tilt, a significant amount of debundling of the nanotubes occurred

(as shown through AFM observations), but laser irradiation led to non-uniformity of the sliced CNTs, and the persistence of longer tubes. Uniform slicing of the CNTs occurred between 7500 

rpm and 8000 rpm when irradiated by the pulsed laser. A tilt angle of 45° angle was found to be optimal, with minimal lateral slicing at other angles between 0 and 90°. For these optimised

VFD processing parameters (θ 45°, rotational speed 7500 rpm), in the absence of the laser pulses there was no evidence for slicing, with the length of the CNTs unchanged, although there was

significant debundling (Supplementary Fig. S1). In decoupling the effect of the VFD and the laser irradiation, a pulsed laser beam of the same optimised power was directed towards the CNTs

in a 1:1 mixture of water and NMP in a glass cuvette rather than in a VFD. This resulted in fragmentation of the CNTs nanotubes into (i) large and irregular shapes for the SWCNTs, (ii) large

bundles and aggregates for the DWCNTs, and (iii) irregular slicing of MWCNTs with bundles and aggregates present (Supplementary Fig. S2). In addition, there was no evidence of slicing the

CNTs with the laser wavelength set to 532 nm (Supplementary Fig. S3). Thus, the optimised parameters for laterally slicing the different CNTs to lengths below _ca_ 450 nm are established as

a 45° tilt angle of the VFD tube rotating at 7500 rpm under confined mode for 30 minutes, with the 10 Hz pulsed laser operating at a wavelength of 1064 nm and 260 mJ per 5 ns pulse. These

conditions were found to be independent of the concentration of CNTs in the solution up to a maximum concentration of 0.1 mg/mL, above which presumably the dynamics in the thin film are

affected by the CNTs. A time dependant study taking samples at 10 minute intervals during 1064 nm laser irradiation at 260 mJ/pulse, and the VFD operating in the confined mode, was also

undertaken for the three types of CNTs. Over time, more slicing and debundling was observed, with SWCNTs resulting in a narrower length distribution, but not so for DWCNTs and MWCNTs (Fig.

2), although here slightly higher yields of sliced CNTs were evident. Experiments under confined mode established the potential for laser irradiation of CNTs in a VFD to produce unbundled,

short CNTs, but for generating practical quantities of the materials, continuous flow processing is desirable. Here a jet feed of CNTs dispersed in a 1:1 mixture of water and NMP was

directed into the bottom of the rapidly rotating 20 mm tube at a low flow rate of 0.45 mL/min, using the same concentration of CNTs as for the confined mode. The low flow rate was necessary

for sufficient exposure time of the CNTs to the 8 mm diameter laser beam, while ensuring droplets of the suspension of the CNTs were striking the hemispherical bottom of the tube rather than

a continuous stream of the liquid. Such droplets result in instability of the resulting thin film, which imparts additional shear compared to the confined mode of operation of the VFD

_(24)_. Under continuous flow there is a dramatic increase in yield of the sliced CNTs, typically 95%, with a length distribution of 100–400 nm, for SWCNTs, DWCNTs and MWCNTs (Fig. 3(b)).

Also noteworthy is that all the samples are devoid of long bundled nanotubes, unlike the outcome for confined mode of operation of the VFD. RAMAN ANALYSIS Raman spectroscopy (Fig. 3(a))

established that any damage to the walls of the CNT products is minimal for confined mode and continuous flow operation of the VFD, irrespective of the number of shells of cylindrical

graphene. Distinct peaks for CNTs include the radial breathing mode region (RBM), the tangential mode G band, its second harmonic G′ band and the disorder-induced D-band. The average ratio

of intensities of the G and D bands (_I__D__/I__G_) of the sliced SWCNT, DWCNT and MWCNT was ~0.2, ~0.3 and 1.2, respectively, which are similar to that of the starting pristine nanotubes

which were ~0.2, ~0.2 and ~1.3, respectively, confirming that tube damage was minimal. SMALL ANGLE NEUTRON SCATTERING ANALYSIS The average size of the sliced CNTs in solution was analysed

using small angle neutron scattering (SANS). The radius of SWCNTs treated with the laser alone and laser and VFD (confined mode, 10, 30 and 60 min) was 0.7 ± 0.2 nm, which is consistent with

AFM results (0.7 to 1.4 nm). For shorter treatment times the nanotubes were longer, and in the absence of VFD processing there is either complete disruption of SWCNTs or no slicing, with

the results consistent with the AFM data (supplementary data). Overall, SWCNTs irradiated and subject to shear are broken down to smaller length scales (Fig. S9–S12), as is the case for the

DWCNTs (Fig. S13) and MWCNTs (Fig. S14), to 160 nm and 171 nm respectively (Table S1), which is again consistent with AFM data. THEORETICAL CALCULATIONS CNTs subjected to the shear forces

created in the VFD result in local bending, as established by the observation that toroidal arrays of SWCNTs are produced in a mixture of toluene and water in the VFD in the absence of laser

irradiation33. Bending is not surprising given the very high aspect ratio for SWCNTs, and when combined with heating from the laser it is likely to result in rupture of multiple bonds. To

explore this further in understanding the mechanism of slicing, molecular dynamics simulations were carried out for SWCNTs, with hairpin-shaped tubes created to mimic the bending occurring

in the VFD. Figure 4a shows a (10, 0) nanotube with a bending radius R of 2.5 nm and an arm-length L of 10 nm. When relaxed near room temperature (Fig. 4b and Movie S1), the hairpin unfolds

and no defects are created. However, when the system is raised to a high temperature (Fig. 4c,d and Movie S2) a large tear occurs in the bent region and other defects appear nearby. The

damage is produced by the extra energy provided by the elevated temperature resulting in breaking of bonds that are already strained. The number of defects induced has been explored for

different bending radii as a function of temperature. Figure 4e shows data for the same (10, 0) chirality with four bending radii, R = 3, 6, 8 and 10 nm. Ten simulations were performed at

each temperature and radius to gather statistics. Defects are counted as atoms with a potential energy 10% higher than the cohesive energy of graphene or with a coordination number other

than three. Below a critical temperature few defects are created, and in many instances no damage is created at all. As the radius increases, the critical temperature above which many

defects are created becomes higher, as the bonds are less strained and require additional thermal activation to damage the nanotube. At large radii few defects are observed (Fig. 4f), even

at high temperatures. These observations explain the experimental result that slicing occurs in the VFD with the laser irradiation but not with laser irradiation alone. Without the shear

forces provided by the VFD, there is no localized bending or strained bonds for the laser to rupture. The simulations also suggest that the diameter D of the nanotube plays a role.

Experimentally, this varies between 1 and 2 nm for the SWNTs. Figure 4g shows defect-vs-diameter data for three different bending radii. Chiralities of (10, 0), (15, 0), (20, 0) and (25, 0)

were chosen with diameters spanning 0.78 to 2.0 nm. All three tubes were heated at 1000 K while bent in a hairpin-shape with radii of 8, 12 and 16 nm. For all three bending radii shown, the

number of defects increases for nanotubes with larger diameter. Larger diameter tubes require less bending (i.e. larger bending radii) to be damaged. For example, while a (10, 0) nanotube

heated at 1000 K needs to be bent to a radius less than 8 nm in order to show any defects, a (15, 0) nanotube shows damage at 8 nm but recovers for larger radii. This occurs due to the

smaller inner bending radii (R-D/2) which arises for larger diameter tubes, while bonds at the outer bending radii are correspondingly stretched, with an outer radius of R + D/2. Therefore,

tubes of larger diameter are more easily sliced. We expect that these simulations of SWCNTs are also applicable to DWCNTs and MWCNTs. Outer tubes will be damaged first, as they have a larger

diameter. Once the outer tube of the MWCNT is breached then the mechanical force either side would provide a point for spontaneously slicing through the inner tubes. In summary, we have

established the ability to laterally slice carbon nanotubes within dynamic thin films, irrespective of the number of concentric layers in the material. This is without precedent, and further

highlights the unique capabilities of the recently developed vortex fluidic device. Importantly, the method minimises the generation of defects on the CNTs, producing pristine material

devoid of chemical stabilisers, and we have demonstrated that there is potential for scalability of the process under continuous flow mode of operation of the VFD. Controlling the lengths of

the shorter nanotubes is more significant for SWCNTs, under confined mode, affording a narrow size distribution at a length scale suitable for drug delivery applications. In general, the

availability of short single, double or multi-walled CNTs is poised for the advancement of their applications where specific length scale is paramount. METHODS PREPARATION OF AQUEOUS

SUSPENSIONS OF SLICED CNTS SWCNTs were purchased from Thomas Swan & Co (UK), as chemical vapour deposition prepared material with an as-received purity >90%, DWCNTs were purchased

from Carbon Allotropes with an as received purity >99% and the MWCNTs were purchased from Sigma Aldrich with an as received purity >98%. Sample preparation included the addition of the

CNTs (1 mg) into a sample vial containing a mixture of NMP and water (6 mL) at a 1:1 ratio. The solution mixture was then ultrasonicated for 10 minutes, affording a black stable dispersion.

Under the confined mode operation, the solution mixture (1 mL) was then placed in the 20 mm borosilicate NMR glass tube (ID 16.000 ± 0.013 mm) and placed in the vortex fluidic device (VFD),

under the optimized rotating speed of 7500 rpm, at a tilt angle of 45 degrees. Simultaneously, a nanosecond pulsed laser processing system with an energy of approximately 260 mJ was applied

to the rapidly rotating system for a period of time (10 minutes, 30 minutes and 1 hour), depending on the resulting length distribution. Under continuous flow mode, jet feeds with a flow

rate at 0.45 mL/min (optimised) deliver the CNT suspension (mixture CNTs in NMP/water at a 1:1 ratio-similar concentration, as for the confined mode) into the rapidly rotating tube.

Centrifugation (g 3.22) of the resulting solution for the confined mode of operation was required to remove any large agglomerates, unsliced bundled CNTs and impurities in the sample. The

centrifugation step was not necessary for the continuous flow mode of operation with _ca_ 95% of the material isolated as sliced CNTs. COMPUTATIONAL DETAILS Starting coordinates were

obtained by geometrically mapping the coordinates of a straight carbon nanotube onto a semicircle of a given radius linked with two straight sections to give a U-shape. Molecular Dynamics

(MD) simulations were performed using the Environmental-Dependent Interaction Potential (EDIP) for carbon37. Prior to the MD step, the structures were relaxed using steepest descent

optimization to remove any forces associated with the mapping. All MD simulations were performed in the NVE (constant particle-volume-energy) ensemble with an integration timestep of 0.35 

fs. The simulations were initialized with velocities drawn from a Maxwell-Boltzmann distribution at a prescribed temperature and the entire system was allowed to evolve for 35 ps. Due to

equipartition, the system temperature during the simulation was very close to half the initial value. Note that all temperatures reported here are system averages, and not the starting

value. Steepest descent optimization was again applied to the final structures to remove any displacements due to thermal vibrations. The resultant structure was then analysed for defects.

Atoms were defined as defects if their coordination number (defined by Equation 9 in Ref. 37) differed by more than 0.1 from the perfect value of 3 or if potential energy was more than 10%

less than the perfect value of −7.361 eV for graphite. INSTRUMENTATION TEM characterizations were carried out using the Phillips CM 200 operating at 200 kV, in the Adelaide Microscopy at the

University of Adelaide. SEM analysis was carried out on the FEI Quanta 450 in Adelaide Microscopy. AFM, Raman characterizations and UV-Vis analysis were performed at Flinders University.

SANS characterizations were carried on QUOKKA at the Bragg Institute, ANSTO. ADDITIONAL INFORMATION HOW TO CITE THIS ARTICLE: Vimalanathan, K. _et al._ Fluid dynamic lateral slicing of high

tensile strength carbon nanotubes. _Sci. Rep._ 6, 22865; doi: 10.1038/srep22865 (2016). REFERENCES * Wong, E. W., Sheehan, P. E. & Lieber, C. M. Nanobeam Mechanics: Elasticity, Strength

and Toughness of Nanorods and Nanotubes. _Science._ 277, 1971–1975 (1997). Article  CAS  Google Scholar  * Liu, L., Yang, C., Zhao, K., Li, J. & Wu, H. C. Ultrashort single walled carbon

nanotubes in a lipid bilayer as a nanopore sensor. _Nature Commun._ 4, 2989 10.1038/ncomms3989 (2013). Article  ADS  CAS  Google Scholar  * Treacy, M. M. J., Ebbesen, T. W. & Gibson, J.

M. Exceptionally high Young’s modulus observed for individual carbon nanotubes. _Nature._ 381, 678–680 (1996). Article  ADS  CAS  Google Scholar  * Krishnan, A., Dujardin, E., Ebbesen, T.

W., Yianilos, P. N. & Treacy, M. M. J. Young’s modulus of single walled nanotubes. _Phys. Rev. B._ 58, 14013–14019 (1998). Article  ADS  CAS  Google Scholar  * Kashyap, K. T. &

Patil, R. G. On Young’s modulus of multiwalled carbon nanotubes. _Bull. Mater. Sci._ 31, 185–187 (2008). Article  CAS  Google Scholar  * Ebbesen, T. W. & Ajayan, P. M. Large scale

synthesis of carbon nanotubes. _Nature._ 358, 220–222 (1992). Article  ADS  CAS  Google Scholar  * Guo, T., Nikolaev, P., Thess, A., Colbert, D. T. & Smalley, R. E. Catalytic growth of

single walled nanotubes by laser vaporisation. _Chem. Phys. Lett._ 243, 49–54 (1995). Article  ADS  CAS  Google Scholar  * Endo, M. et al. The production and structure of pyrolytic carbon

nanotubes. _J. Phys. Chem. Solids._ 54, 1841–1848 (1997). Article  ADS  Google Scholar  * Javey, A. et al. High Field Quasiballistic Transport in Short Carbon Nanotubes. _Phys. Rev. Lett._

92, 16804 1–4 (2004). Article  Google Scholar  * Kalita, G. et al. Cutting carbon nanotubes for solar cell applications. _Appl. Phys. Lett._ 92, 12358 10.1063/1.290349 (2008). Article 

Google Scholar  * Farkas, E., Anderson, M. E., Chen, Z. & Rinzler, A. G. Length sorting cut single walled carbon nanotubes by high performance liquid chromatography. _Chem. Phys. Lett._

363, 111–116 (2002). Article  ADS  CAS  Google Scholar  * Sanchez-Valencia, J. R. et al. Controlled synthesis of single chirality carbon nanotubes. _Nature_, 512, 61–64 (2014). Article  ADS

  CAS  PubMed  Google Scholar  * Casey, J. P., Bachilo, S. M., Moran, C. H. & Weisman, R. B. Chirality-resolved length analysis of single walled carbon nanotube samples through shear

aligned photoluminescence anisotropy. _ACS Nano_, 2, 1738–1746 (2008). Article  CAS  PubMed  Google Scholar  * Minati, L. et al. Investigation on the Electronic and Optical Properties of

Short Oxidised Multiwalled Carbon Nanotubes. _J.Phys. Chem. C._ 114, 11068–11073 (2010). Article  CAS  Google Scholar  * Tran, M. Q., Tridech, C., Alfrey, A., Bismarck, A. & Shaffer, M.

S. P. Thermal oxidative cutting of multiwalled carbon nanotubes. _Carbon._ 45, 2341–2350 (2007). Article  CAS  Google Scholar  * Wang, C., Guo, S., Pan, X., Chen, W. & Bao, X. Tailored

cutting of carbon nanotubes and controlled dispersion of metal nanoparticles inside their channels. _J. Mater. Chem._ 18, 5782–5786 (2008). Article  CAS  Google Scholar  * Yudasaka, M.,

Zhang, M., Jabs, C. & Iijima, S. Effect of an organic polymer in purification and cutting of single walled carbon nanotubes. _App. Phys. A._ 71, 449–451 (2000). Article  ADS  CAS  Google

Scholar  * Zhang, J. et al. Effect of chemical oxidation on the structure of single walled carbon nanotubes. _J. Phys. Chem. B._ 107, 3712–3718 (2003). Article  CAS  Google Scholar  * Liu,

J. et al. Fullerene pipes. _Science._ 280, 1253–1256 (1998). Article  ADS  CAS  PubMed  Google Scholar  * Gu, Z., Hauge, R. H., Smalley, R. E. & Margrave, J. L. Cutting single walled

carbon nanotubes through fluorination. _Nano Letters._ 2, 1009–1013 (2002). Article  ADS  CAS  Google Scholar  * Pierard, N. et al. Ball milling effect on the structure of single walled

carbon nanotubes. _Carbon._ 42, 1691–1697 (2004). Article  CAS  Google Scholar  * Chen, Z. et al. Soluble ultra-short single walled carbon nanotubes. _J. Am. Chem. Soc._ 128, 10568–10571

(2006). Article  CAS  PubMed  Google Scholar  * Yi, X. J., Nadeem, A. M., Dong, B. H., Ying, L. H. & Tai, Y. W. Concentration and temperature controlled oxidation and cutting of single

walled carbon nanotubes by ammonium persulfate. _Sci Chi._ 53, 2026–2032 (2010). Article  Google Scholar  * Zhao, J., Liu, P., Yang, Z., Zhou, P. & Zhang, Y. One-step cutting of

multiwalled carbon nanotubes using nanoscissors. _Nano-Micro Lett._ 2, 86–90 (2011). Article  Google Scholar  * Manivannan, S. et al. Dispersion of single walled carbon nanotubes in aqueous

and organic solvents through polymer wrapping functionalisation. _J. Mater. Sci._ 20, 223–229 (2009). CAS  Google Scholar  * Tkalya, E. E., Ghislandi, M., With, G. D. & Koning, C. E. The

use of surfactants for dispersing carbon nanotubes and graphene to make conductive nanocomposites. _Curr. Opin. Coll. Inter._ 17, 225–232 (2012). Article  CAS  Google Scholar  * Mickelson,

E. T. et al. Solvation of flourinated single walled carbon nanotubes in alcohol solvents. _J. Phys. Chem. B._ 103, 4318–4322 (1999). Article  CAS  Google Scholar  * Boul, P. J. et al.

Reversible sidewall functionalisation of bucky tubes. _Chem. Phys. Lett._ 310, 367–372 (1999). Article  ADS  CAS  Google Scholar  * Britton, J., Chalker, J. M. & Raston, C. L. Rapid

vortex fluidics: Continuous flow synthesis of amides and local anaesthetic lidocaine. _Chem. Eur. J._ 21, 10660–106665 (2015). Article  CAS  PubMed  Google Scholar  * Britton, J., Dalziel,

S. B. & Raston, C. L. Continuous flow Fischer esterifications harnessing vibrational-coupled thin films fluidics. _RSC Adv._ 5, 1655–1660 (2015). Article  CAS  Google Scholar  * Chen,

X., Dobson, J. F. & Raston, C. L. Vortex fluidic exfoliation of graphite and boron nitride. _Chem. Commun._ 48, 3703–3705 (2012). Article  CAS  Google Scholar  * Yuan, T. Z. et al.

Shear-stress-mediated refolding of proteins from aggregates and inclusion bodies. _ChemBioChem._ 16, 393–396 (2015). Article  CAS  PubMed  PubMed Central  Google Scholar  * Vimalanathan, K.,

Chen, X. & Raston, C. L. Shear induced fabrication of intertwined single walled carbon nanotube rings. _Chem Commun._ 50, 11295–11298 (2014). Article  CAS  Google Scholar  * Tong, C.

L., Boulos, R. A., Yu, C., Iyer, K. S. & Raston, C. L. Continuous flow tuning of ordered mesoporous silica under ambient conditions. _RSC Adv._ 3, 18767–18770 (2013). Article  CAS 

Google Scholar  * Mo, J. et al. Shear induced carboplatin binding within the cavity of a phospholipid mimic for increased anticancer efficacy. _Sci. Rep._ 5, 10414 10.1038/srep10414 (2015).

Article  ADS  PubMed  PubMed Central  Google Scholar  * Iyer, K. S. & Raston, C. L. Fabrication of laterally ‘sliced’ metal plated carbon nanotubes under aqueous continuous flow

conditions. _J. Mater. Chem._ 17, 4872–4875 (2007). Article  CAS  Google Scholar  * Marks, N. A. Generalizing the environment-dependent interaction potential for carbon. _Phys. Rev. B._ 63,

035401 10.1103/PhysRevB.63.035401 (2000). Article  ADS  CAS  Google Scholar  Download references ACKNOWLEDGEMENTS The authors thank Dr. Paul Eggers for his technical assistance, and

Associate Professor Amanda Ellis for discussions on the optical absorbance characterisations. The authors also thank Australian Research Council and The Government of South Australia for

support of the work. AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Flinders Centre for NanoScale Science & Technology, School of Chemical & Physical Sciences, Flinders University,

Adelaide, 5001, SA, Australia Kasturi Vimalanathan, Jason R. Gascooke, Warren D. Lawrance & Colin L. Raston * Department of Physics and Astronomy, Nanochemistry Research Institute,

School of Science, Curtin University, Bentley Campus, Perth, 6102, WA, Australia Irene Suarez-Martinez & Nigel A. Marks * Department of Chemistry, University of Missouri, 601 South

College Avenue, Columbia, 65211, Missouri, United States Harshita Kumari & Jerry L. Atwood * James L. Winkle College of Pharmacy, University of Cincinnati, 3225 Eden Avenue, Cincinnati,

42567, Ohio, United States Harshita Kumari * Bragg Institute, Australian Nuclear Science and Technology Organisation, New Illawarra Road, 2234, Lucas Heights, NSW Christopher J. Garvey

Authors * Kasturi Vimalanathan View author publications You can also search for this author inPubMed Google Scholar * Jason R. Gascooke View author publications You can also search for this

author inPubMed Google Scholar * Irene Suarez-Martinez View author publications You can also search for this author inPubMed Google Scholar * Nigel A. Marks View author publications You can

also search for this author inPubMed Google Scholar * Harshita Kumari View author publications You can also search for this author inPubMed Google Scholar * Christopher J. Garvey View author

publications You can also search for this author inPubMed Google Scholar * Jerry L. Atwood View author publications You can also search for this author inPubMed Google Scholar * Warren D.

Lawrance View author publications You can also search for this author inPubMed Google Scholar * Colin L. Raston View author publications You can also search for this author inPubMed Google

Scholar CONTRIBUTIONS K.V., J.R.G., W.D.L., N.M., I.S.M., H.K., J.L.A. and C.L.R. designed the experiments and wrote the paper, K.V. and J.R.G. performed the slicing experiments. K.V.

carried out AFM, Raman and UV Vis analysis and analysed the data. N.M. and I.S.M. carried out the computational studies and the data analysis. H.K. and C.G. carried out SANS experiments and

H.K. and J.L.A. carried out the data analysis based on the SANS results. CORRESPONDING AUTHOR Correspondence to Colin L. Raston. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare

no competing financial interests. SUPPLEMENTARY INFORMATION SUPPLEMENTARY INFORMATION (PDF 8254 KB) SUPPLEMENTARY MOVIE S1 (MOV 13856 KB) SUPPLEMENTARY MOVIE S2 (MOV 15356 KB) RIGHTS AND

PERMISSIONS This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s

Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the

license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE

Vimalanathan, K., Gascooke, J., Suarez-Martinez, I. _et al._ Fluid dynamic lateral slicing of high tensile strength carbon nanotubes. _Sci Rep_ 6, 22865 (2016).

https://doi.org/10.1038/srep22865 Download citation * Received: 15 October 2015 * Accepted: 22 February 2016 * Published: 11 March 2016 * DOI: https://doi.org/10.1038/srep22865 SHARE THIS

ARTICLE Anyone you share the following link with will be able to read this content: Get shareable link Sorry, a shareable link is not currently available for this article. Copy to clipboard

Provided by the Springer Nature SharedIt content-sharing initiative