Future trends in carbon nanotubes: Process towards a viable biomedical solution

Background: Recently, Nanomaterials based nano-composite materials play the role of various field. Especially, Carbon nanotube based materials are involved in the bio-medical applications.Since, their exclusive and exciting property, researchers worldwide have extensively involved in trans-modulating the carbon nanotubes into a viable medico-friendly system. Objective: These active researches paved the path towards targeted drug delivery, diagnostic techniques, and bio-analytical applications. Despite these exciting properties, which accomplish the probable for biomedical applications, they hold Biosafety issues. Methods: This broad-spectrum review has discussed different aspects of carbon nanotubes and carbon nanotube-based systems related to biomedical applications. Results: Adding to this, a short chronological description of these tiny yet powerful particles given, followed by a discussion regarding their types, properties, methods of synthesis, scale-up, purification techniques and characterization aspects of carbon nanotubes. Conclusion: In the later part, the functionalization of carbon nanotubes was reviewed in detail, which is important to make them biocompatible and stable in biological systems and render them a great property of loading various biomolecules diagnostic and therapeutic moieties. Lastly, an inclusive description of the potential biomedical applications has been given followed by insights into the future.

Synthesis of a Poly(3-dodecylthiophene) Bearing Aniline Groups for the Covalent Functionalization of Carbon Nanotubes

The functionalization of carbon nanotubes by polymers necessitates two steps, first their modification by oxidizing them or by covalently attaching small compounds to them, then the growth of the polymer chains from these anchors or their grafting onto them. In order to better control the process and the rate of functionalization, we develop polymers able to covalently react with the carbon nanotubes by their side chains in one step. We describe the synthesis of a copolymer of dodecylthiophene and its analogue bearing an aniline group at the end of the dodecyl side chain. This copolymer can functionalize single-walled carbon nanotubes (SWNTs) non-covalently and disperse more SWNTs than its hexyl analogues. UV-Vis and fluorescence spectroscopies show that in these non-covalent hybrids, the polymer forms p-stacked aggregates on the SWNTs. The non-covalent hybrids can be transformed into covalent ones by diazonium coupling. In these covalent hybrids the polymer is no longer p-stacked. According to Raman spectroscopy, the conformation of the poly(3-hexylthiophene) backbone is more ordered in the non-covalent hybrids than in the covalent ones.

Thermal and Structural Properties of High Density Polyethylene/Carbon Nanotube Nanocomposites: A Comparison Study

The effects of functionalization of carbon nanotubes on the properties of nanocomposite sheets prepared from high-density polyethylene (HDPE) and carbon nanotubes (CNTs) were investigated. Carbon nanotubes were first oxidized, followed by amine group functionalization. The Fourier transform-infrared (FTIR) spectroscopy results confirm the presence of oxygenated and amide groups at the surface of the CNTs after each treatment. The HDPE/CNT nanocomposites sheets were prepared using a melt compounding method. Six types of CNTs were used; pristine Single-walled Carbon nanotubes (SWCNT) and pristine Multi-walled Carbon nanotubes (MWCNT), oxidized (O-SWCNT and O-MWCNT) and amide (Amide-SWCNT and Amide-MWCNT). All prepared nanocomposite sheets were characterized using Thermal gravimetric analysis (TGA), Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electronic microscope (SEM). TGA results measured increased thermal stability of the polymer with the addition of CNTs, O-MWCNT showed the best enhancement. XRD measurements confirmed that the addition of CNTs did not change the crystal structure of the polymer, although the crystallinity was decreased. The maximum crystallinity decrease resulted from O-SWNTs addition to the polymer matrix. SEM imaging showed that oxidized and functionalized CNTs have more even dispersion in the polymer matrix compared with pristine CNTs.

Chemical Functionalization of Carbon Nanotubes with Polymers: A Brief Overview

Carbon nanotubes (CNTs), the one-dimensional allotropes of carbon, have attracted noteworthy research interest since their discovery in 1991 owing to their large aspect ratio, low mass density, and unique chemical, physical, and electronic properties that provide exciting possibilities for nanoscale applications. Nonetheless, two major issues should be considered when working with this sort of nanomaterial: their strong agglomerating tendency, since they are typically present as bundles or ropes of nanotubes, and the metallic impurities and carbonaceous fragments that go along with the CNTs. The successful utilization of CNTs in a wide variety of applications—in particular, in the field of polymer composites—depends on their uniform dispersion and the development of a strong chemical interaction with the polymeric matrix. To achieve these aims, chemical functionalization of their sidewalls and tips is required. In this article, a brief overview of the different approaches for CNT modification using polymers is provided, focusing on the covalent functionalization via “grafting to” or “grafting from” strategies. The characteristics and advantages of each approach are thoroughly discussed, including a few typical and recent examples. Moreover, applications of polymer-grafted CNTs as biosensors, membranes, energy storage substances, and EMI shielding are briefly described. Finally, future viewpoints in this vibrant research area are proposed.

Combined Functionalization of Carbon Nanotubes (CNT) Fibers with H2SO4/HNO3 and Ca(OH)2 for Addition in Cementitious Matrix

Acid treatment is commonly used to improve the dispersion of carbon nanotubes (CNT) in a cementitious matrix, but it causes undesired delay on cement hydration kinetics. This work reports a combined CNT functionalization method with H2SO4/HNO3 and Ca(OH)2 for addition in a cementitious matrix. Results showed that the Ca(OH)2 exposure neutralized the active sites generated by acid exposure, compensating the delay in hydration. As a result, CNT exposed to H2SO4/HNO3 for 9 h and further Ca(OH)2 treatment led to equivalent hydration kinetics than un-treated CNT did with improved stability.