Properties of carbon nanotube–polymer composites aligned in a magnetic field

Camponeschi, Erin; Vance, Richard; Al-Haik, Marwan; Garmestani, Hamid; Tannenbaum, Rina

doi:10.1016/j.carbon.2007.05.024

Cited by 187 publications

(106 citation statements)

References 69 publications

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“…There exist several experimental works that display enhancement of mechanical properties of CNT-based composites by application of magnetic fields [5,6]. This fact is the chief motivation of this study.…”

Section: Introductionmentioning

confidence: 95%

Nonlocal Timoshenko Beam for Vibrations of Magnetically Affected Inclined Single-Walled Carbon Nanotubes as Nanofluidic Conveyors

Kiani

2017

Acta Phys. Pol. A

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This work displays both longitudinal and transverse vibrations of magnetically affected inclined single-walled carbon nanotubes for conveying fluid flow. By employing an equivalent continuum structure on the basis of the nonlocal Timoshenko beam model as well as plug-like model for the nanofluidic flow inside the pore, the nonlocal governing equations are obtained accounting for nonlocality, frictionless nature of the inside wall, the Knudsen number, and full longitudinal and transverse interactions of the fluid flow with the single-walled carbon nanotubes. By implementing Galerkin-based assumed mode method, the equations of motion are discretized appropriately and then solved for the unknown dynamical deformation fields. The roles of nanofluidic flow velocity, small-scale parameter, inclination angle of single-walled carbon nanotube, and magnetic field strength on maximum values of longitudinal and transverse displacements are explained and discussed. The results show that the maximum dynamic deflection of the inclined nanotube would lessen by increase of the magnetic field strength. This fact is also more apparent for higher levels of fluid flow velocity. Additionally, variation of the longitudinal magnetic field has a trivial influence on the variation of longitudinal displacement. The predicted results reveal that application of the longitudinal magnetic field could be used as an efficient methodology to reduce the lateral vibrations of single-walled carbon nanotubes as nanofluidic conveyors.

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Section: Introductionmentioning

confidence: 95%

Nonlocal Timoshenko Beam for Vibrations of Magnetically Affected Inclined Single-Walled Carbon Nanotubes as Nanofluidic Conveyors

Kiani

2017

Acta Phys. Pol. A

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“…However, due to the low magnetic susceptibility of CNTs, their alignment by the application of an external magnetic field requires a relatively high magnetic field (Camponeschi et al, 2007). This drawback could be eliminated by enhancing the magnetic susceptibility of carbon nanotubes via the tethering of magnetic nanoparticles onto their surface.…”

Section: Electronic Properties Of Carbon Nanotubes 34mentioning

confidence: 99%

“…More recently, Steinert and Dean (Steinert & Dean, 2009) obtained solution cast PET-carbon nanotube composite films by applying a magnetic field, resulting in increased conductivity with the increase of the applied magnetic field. Furthermore, in our previous study (Camponeschi et al, 2007), we prepared magnetically aligned carbon nanotube composite systems; thus, carbon nanotubes were aligned parallel to the direction of magnetic field, resulting in enhanced mechanical properties. However, due to the low magnetic susceptibility of carbon nanotubes, their alignment by the application of an external magnetic field requires a relatively high magnetic field.…”

Section: Alignment Strategies Of Carbon Nanotubes In Polymer Matricesmentioning

confidence: 99%

Magnetic Carbon Nanotubes: Synthesis, Characterization, and Anisotropic Electrical Properties

Kim¹,

Tannenbaum²

2011

Electronic Properties of Carbon Nanotubes

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Electronic Properties of Carbon Nanotubes 34The alignment of CNTs in a variety of matrices can be used to reinforce, intensify, and enhance some of the properties of the resulting systems, as well as introduce various degrees of anisotropy into the properties of the desired nanomaterials (Kimura et al., 2002;Garmestani et al., 2003). The alignment of CNTs in a suspension under a magnetic field requires that the energy produced by the torque acting on a magnetically-anisotropic segment exceeds the thermal energy of that particular segment, such that:, where B is the field strength, n is the number of carbon atoms in the segment, and  is the magnetic anisotropy (Fisher et al., 2003). However, due to the low magnetic susceptibility of CNTs, their alignment by the application of an external magnetic field requires a relatively high magnetic field (Camponeschi et al., 2007). This drawback could be eliminated by enhancing the magnetic susceptibility of carbon nanotubes via the tethering of magnetic nanoparticles onto their surface. In zero field, the magnetic moments of the maghemite nanoparticles randomly point in different directions, resulting in a vanishing net magnetization. However, if a sufficient homogeneous magnetic field is applied, the magnetic moments of the nanoparticles align in parallel, and the resulting dipolar interactions are sufficiently large to overcome thermal motion and to reorient the magnetic CNTs.In this chapter, we describe and report a convenient approach for the decoration of CNTs with near-monodisperse maghemite nanoparticles by employing a novel and simple modified sol-gel process (in-situ process) with a n i r o n s a l t a s p r e c u r s o r , f o l l o w e d b y calcination. The resulting hybrid nanomaterials are superparamagnetic at room temperature and are conducive to facile alignment under relatively low magnetic fields. Subsquently, the nanohybrid materials, i.e. the magnetized carbon nanotubes, were incorporated into a polymer matrix and aligned by the application of a magnetic field, forming polymer composites with an aligned filler phase. It is therefore expected that the composites formed in this manner would exhibit anisotropic mechanical and electrical properties that would depend on and correlate with the parallel and perpendicular direction to the magnetic field that has been applied and under which the alignment has taken place. Experimental details 2.1 Synthesis of maghemite-MWCNT nanohybrid materialsPure-MWCNTs were first dispersed in a solution mixture of concentrated H 2 SO 4 and HNO 3 with the volume ratio of 3:1. The suspension was ultra-sonicated for 3 hrs at room temperature. After that, the concentration of the suspension was diluted up to 50% and filtered with a PTFE membrane (0.45 μm pore size) with the aid of a vacuum pump. Carboxylated MWCNT (MWCNT-COOH) was washed with de-ionized water several times to reach neutral pH and dried under vacuum at 50 °C overnight. The synthesis of maghemite-MWCNT was performed by first adding 0.65 g Fe(NO 3 ) 3 ·9H 2 O to ...

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“…The composite was cured at 150°C for 4 h, followed by post curing at 180°C for 1 h. SEM images showed that the CNTs were mostly buried inside the epoxy matrix with aggregation of some of the CNTs. Camponeschi et al [Camponeschi et al, 2007] investigated the effect of orientation and alignment of MWCNTs embedded in different epoxy polymer matrices [Aeropoxy (AP) and Coldfix ] under an external magnetic field. The CNTs were dispersed in the resin through ultrasonication.…”

Section: Swcnt Graphene Sheetmentioning

confidence: 99%