Carbon nanotubes: Amino functionalization and its application in the fabrication of Al-matrix composites

Critical challenges and advances in the carbon nanotube-metal interface for next-generation electronics

Next-generation electronics can no longer solely rely on conventional materials; miniaturization of portable electronics is pushing Si-based semiconductors and metallic conductors to their operational limits, flexible displays will make common conductive metal oxide materials obsolete, and weight reduction requirement in the aerospace industry demands scientists to seek reliable low-density conductors. Excellent electrical and mechanical properties, coupled with low density, make carbon nanotubes (CNTs) attractive candidates for future electronics. However, translating these remarkable properties into commercial macroscale applications has been disappointing. To fully realize their great potential, CNTs need to be seamlessly incorporated into metallic structures or have to synergistically work alongside them which is still challenging. Here, we review the major challenges in CNT-metal systems that impede their application in electronic devices and highlight significant breakthroughs. A few key applications that can capitalize on CNT-metal structures are also discussed. We specifically focus on the interfacial interaction and materials science aspects of CNT-metal structures.

Influence of biosafe amino acid-functionalized multiwalled carbon nanotubes on the morphology and thermal properties of the poly(amide–imide) nanocomposites containing N,N′-(pyromellitoyl)-bis-S-valine segments

In this study, S-valine-functionalized multiwalled carbon nanotubes (f-MWCNTs)/poly(amide–imide) (PAI) bionanocomposites (BNC)s were prepared by a simple ultrasonication-assisted solution blending process. First, carboxylated MWCNTs were functionalized with S-valine to achieve a fine dispersion of f-MWCNT bundles in the PAI matrix due to hydrogen bonding and π–π stacking interaction between f-MWCNTs and polymer functional groups and aromatic moieties. The existence of S-valine as a biodegradable segment in both f-MWCNTs and optically active PAI provided potentially biodegradable nanocomposites and caused compatibility between f-MWCNTs and the polymer matrix. The obtained BNCs were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The TEM and FESEM images confirmed good dispersion of f-MWCNTs in the polymer matrix. The results of TGA and XRD analysis suggested that a good thermal stability and dispersion occurred especially with low filler amounts (5 wt%) of f-MWCNTs.

Mechanochemistry of fullerenes and related materials

The low or lack of solubility of fullerenes, carbon nanotubes and graphene/graphite in organic solvents and water severely hampers the study of their chemical functionalizations and practical applications. Covalent and noncovalent functionalizations of fullerenes and related materials via mechanochemistry seem appealing to tackle these problems. In this review article, we provide a comprehensive coverage on the mechanochemical reactions of fullerenes, carbon nanotubes and graphite, including dimerizations and trimerizations, nucleophilic additions, 1,3-dipolar cycloadditions, Diels-Alder reactions, [2 + 1] cycloadditions of carbenes and nitrenes, radical additions, oxidations, etc. It is intriguing to find that some reactions of fullerenes can only proceed under solvent-free conditions or undergo different reaction pathways from those of the liquid-phase counterparts to generate completely different products. We also present the application of the mechanical milling technique to complex formation, nanocomposite formation and enhanced hydrogen storage of carbon-related materials.