Carbon nanotubes (CNTs) hold the promise of delivering exceptional mechanical properties and multi-functional characteristics. Ever-increasing interest in applying CNTs in many different fields has led to continued efforts to develop dispersion and functionalization techniques. To employ CNTs as effective reinforcement in polymer nanocomposites, proper dispersion and appropriate interfacial adhesion between the CNTs and polymer matrix have to be guaranteed. This paper reviews the current understanding of CNTs and CNT/polymer nanocomposites with two particular topics: (i) the principles and techniques for CNT dispersion and functionalization and (ii) the effects of CNT dispersion and functionalization on the properties of CNT/polymer nanocomposites. The fabrication techniques and potential applications of CNT/polymer nanocomposites are also highlighted.

Dispersion and functionalization of carbon nanotubes for polymer-based nanocomposites: a review

Thermal conductivity of carbon nanotubes and their polymer nanocomposites: A review

Electrically conductive polyethylene terephthalate/graphene nanocomposites prepared by melt compounding

The controlled synthesis of materials by methods that permit their assembly into functional nanoscale structures lies at the crux of the emerging field of nanotechnology. Although only one of several materials families is of interest, carbon-based nanostructured materials continue to attract a disproportionate share of research effort, in part because of their wide-ranging properties. Additionally, developments of the past decade in the controlled synthesis of carbon nanotubes and nanofibers have opened additional possibilities for their use as functional elements in numerous applications. Vertically aligned carbon nanofibers (VACNFs) are a subclass of carbon nanostructured materials that can be produced with a high degree of control using catalytic plasma-enhanced chemical-vapor deposition (C-PECVD). Using C-PECVD the location, diameter, length, shape, chemical composition, and orientation can be controlled during VACNF synthesis. Here we review the CVD and PECVD systems, growth control mechanisms, catalyst preparation, resultant carbon nanostructures, and VACNF properties. This is followed by a review of many of the application areas for carbon nanotubes and nanofibers including electron field-emission sources, electrochemical probes, functionalized sensor elements, scanning probe microscopy tips, nanoelectromechanical systems (NEMS), hydrogen and charge storage, and catalyst support. We end by noting gaps in the understanding of VACNF growth mechanisms and the challenges remaining in the development of methods for an even more comprehensive control of the carbon nanofiber synthesis process.

Vertically Aligned Carbon Nanofibers and Related Structures: Controlled Synthesis and Directed Assembly

Electrically conductive polymeric materials have recently attracted considerable interest from academic and industrial researchers to explore their potential in biomedical applications such as in biosensors, drug delivery systems, biomedical implants and tissue engineering. Conventional conductive homopolymers such as polypyrrole and PEDOT show promising conductivity for these applications, however their mechanical properties, biocompatibility and processability are often poor. This has led to more recent attention being directed towards conductive polymeric composites comprised of biostable/biocompatible polymers with dispersed conductive fillers such as graphene, carbon nanotubes and metallic nanoparticles. The major objective of this paper is to provide an up to date review of the recent investigations conducted in the development of conductive polymer composites focussing on the methods of their preparation, underlying concepts of their conductivity and the ways to tailor their properties. Furthermore, recent progress made in conventional conducting polymers and their composites/blends for biomedical applications is also discussed.

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Electrically conductive polymers and composites for biomedical applications

Microstructure of carbon nanotubes/PET conductive composites fibers and their properties

The present invention relates to a way to manufacture carbon nanotubes (CNTs) continuously in a novel nano-agglomerate fluidized-bed and the reactor (NAFBR). It belongs to material and chimical engineering fields. The procedure includes loading transition metal compounds on a support, obtaining a supported catalyst of metal nanoparticles by deoxidization or heater decomposition, catalytic pyrolyzing carbon source gases and vapor depositing of carbon atoms in a NAFBR. CNTs 4∩100 nm in diameter and 0.5∩1000 µm in length have been synthesized on catalyst supports. As the result of a careful choice of the catalysts, as well as the agglomerate structures and size, CNT agglomerates ranged 1∩1000 µm have been smoothly fluidized under 0.005∩2 m/s superficial gas velocity. The bed density is ranged 20∩800 kg/m3 in the NAFBR. This unit is simple and easy to be operated in a high intensity, and it can be used to produce high-purity CNTs with graphitoid walls in high-yield.

Continuous mass production of carbon nanotubes in a nano-agglomerate fluidized-bed and the reactor

The evaluation of the gross defects of carbon nanotubes in a continuous CVD process

Effect of adding nickel to iron–alumina catalysts on the morphology of as-grown carbon nanotubes

Preparation of carbon nanotubes (CNTs) by catalytic chemical vapor deposition (CCVD) was conducted using a nano-agglomerate bed of quartz with 44 mm inner diameter and 1000 mm height in the temperature range 500–650°C. Ethylene and propylene were used as carbon source materials, and four kinds of catalysts containing oxides of Fe, Cu, and Ni, prepared by co-precipitation method, were used. Effect of catalyst composition on morphology of CNTs was studied by transmission electron microscopy (TEM). It shows that better quality CNTs can be achieved with Fe-catalysts, and carbon nano-fibers were produced at high carbon yield with Ni-catalysts.

Zhifei Li

Papers

Microstructure of carbon nanotubes/PET conductive composites fibers and their properties

Continuous mass production of carbon nanotubes in a nano-agglomerate fluidized-bed and the reactor

The evaluation of the gross defects of carbon nanotubes in a continuous CVD process

Effect of adding nickel to iron–alumina catalysts on the morphology of as-grown carbon nanotubes

Catalysts effect on morphology of carbon nanotubes prepared by catalytic chemical vapor deposition in a nano-agglomerate bed