Chemistry of Carbon Nanotubes
The article begins with providing an introduction to the different properties of Carbon nanotubes and how they could be used in the material science and medicinal chemistry fields. The articles continued on by saying that the discovery of carbon nanotubes has started further research in the nanotechnology field. Then the article went into more detail about describing the material, average length, and the arrangement of the carbon nanotubes. The different applications of carbon nanotubes are (as of the publication of this article): filters in polymer matrixes, molecular tanks, and biosensors. Some of the disadvantages they found while experimenting with carbon nanotubes are the lack of solubility, and the difficulty of manipulation in any solvent. However, some ways researchers have found on how to modify carbon nanotubes are by covalent attachment, and noncovalent adsorption.
Spinning continuous carbon nanotube yarns
An experiment was conducted to create a string of carbon nanotube yarn. The purpose of this was to create an efficient way to construct nanotube devices and structures. They found the longest yarn length they could construct was up to 30cm in length and 200um in width by drawing the yarn out from superaligned arrays of carbon nanotubes. They also created another experiment that involved placing one of the carbon nanotube yarns between light bulb filaments to measure the different properties when the light bulb was on. They found that after three hours, both the conductivity and the tensile strength increased. Some different applications of carbon nanotube yarns are bulletproof vests, and materials that block electromagnetic waves.
Water-Assisted Highly Efficient Synthesis of Impurity-Free Single-Walled Carbon Nanotubes
Experiment conducted to demonstrate the efficient chemical vapor deposition synthesis of single walled carbon nanotubes where the catalyst activity and lifetime are enhanced by water. The catalytic activity resulted in a large growth of very dense and vertically aligned nanotubes with the heights up to 2.5 mm. The carbon nanotubes could then be easily separated from the catalysts with carbon purity above 99.98%, and be patterned in highly organized intrinsic nanotube arrays. The purpose of the experiment was to address any of the critical problems that are currently in the synthesis of carbon nanotubes.
NANOSCALE HYDRODYNAMICS: Enhanced flow in carbon nanotubes
The purpose of this experiment was to create nanostructure that could mimic the selective transport and extraordinarily fast flow possible in biological cellular channels for a variety of different applications. From the results, they found the liquid flow through a membrane created out of carbon nanotubes is four to five times faster than what was previously predicted. The high flow rate resulted from an almost frictionless interface between the carbon nanotube walls. Other thoughts of creating the inside wall of the carbon nanotubes to be hydrophobic as to increase the velocity of the flow rate were also thought of. During the experiment, the only time researchers found a decrease in the flow rate of hydrogen-bonded fluids was after a few minutes because of the formation of “Bubbles” in the carbon nanotubes. They also noticed how the flip length affects the flow rate; as the slip length decreased, the solvents became more hydrophobic.
HYDROGEN STORAGE IN SINGLE-WALLED CARBON NANOTUBES AT ROOM TEMPERATURE
A hydrogen storage capacity of 4.2 wt. % was achieved reproducibly at room temperature under a modestly high pressure (about ten MPa) for a SWCNT sample of about 500mg that was soaked in hydrochloric acid and then heat-treated in vacuum. Moreover, 78% of the adsorbed hydrogen could be released under ambient pressure at room temperature. Other tests were conducted by changing the temperature, pressure and time to explore other options. The most successful test was on sample 2 was soaked in 37% HCL acid for 48 hours, rinsed with deionized water, and dried at 150 °C. The process of Semi-continuous hydrogen arc discharge technique was used for the synthesis of the SWCNT yielding at about 2g per hour through this process.
Opening carbon nanotubes with oxygen and implications for filling
Capped hollow carbon nanotubes can be modified into nanocomposite fibers by simultaneous opening of the caps (by heating in the presence of air and lead metal) and filling of the interior with an inorganic phase. The carbon nanotubes are oxidized in air for short period of time above 700 °C results in the etching away of the caps and the outer layers, starting from the cap region. The oxidation reaction follows an Arrhenius-type relation with an activation energy barrier of about 225kJ mol-1 in air. Heating of closed nanotubes with Pb3O4 in the air opens the carbon nanotubes at lower temperatures. However, open tubes are much more difficult to fill with inorganic materials than in one-step filling. But various other experiments might be possible in the inner nano-cavities of the open tubes such as studies of catalysis and of low-dimensional chemistry and physics.
Single-walled carbon nanohorns as drug carriers: adsorption of prednisolone and anti-inflammatory effects on arthritis
Prednisolone (PSL) was adsorbed on oxidized single-walled carbon nanohorns (oxSWNHs) in ethanol–water solvent. The quantity of adsorbed PSL on the oxSWNHs was 0.35–0.54 g/g depending on the sizes and numbers of holes on the oxSWNHs. PSL was adsorbed on both the outside and the inside of the oxSWNHs and released quickly in a couple of hours and slowly within about one day, respectively. The released quantity in culture medium depended on the concentration of the PSL–oxSWNH, advising that PSL adsorbed on oxSWNHs and PSL in the culture medium were in equilibrium. The injection of PSL–oxSWNHs into the tarsal joint of rats with arthritis slightly slowed the progression of the arthritis. The analysis of the ankle joint, the anti-inflammatory effect of PSL–oxSWNHs was also observed.
Reviewing the Environmental and Human Health Knowledge Base of Carbon Nanotubes
The widespread projected use of carbon nanotubes makes it important to understand the potential harmful effects. In the article, they observed a range of results from some of the toxicology studies. As of this article, it shows some key points such as exposure to carbon nanotubes, and human and environmental health effects. In organisms, the absorption, distribution, metabolism, and toxicity of carbon nanotubes depends on the natural physical and chemical characteristics of carbon nanotubes such as coating, length, and mass. Exposure situations would be useful when conducting toxicologic studies. Lastly, carbon nanotubes produce a toxic reaction when reaching the lungs in large quantity.
Toxicity issues in the application of carbon nanotubes to biological systems
The article explores the possible toxicologic implications of carbon nanotubes in Nano medicine. Even though one application works, that doesn’t mean the carbon nanotubes in biological systems because of inconsistent data on cytotoxicity and limited control over carbon nanotubes, both of which limit predictability. Also the lack of a toxicity database limits comparison between research results. To better understand the problems, researchers needed data from newer toxicity studies, with data suggesting post exposure regeneration, resistance, and mechanisms of injury in cells, by carbon nanotubes.
The behavioral and developmental physiology of nematocysts
Nematocysts are the nonliving secretions of specialized cells, which develop from stem cells. Nematocysts are what jellyfish use to capture prey and defend against predators. Of the different types of nematocysts, they fall into to four categories: those that pierce, ensnare, or adhere to prey, and those that adhere to the substrate. During development a collagenous cyst (which may contain toxins) forms a hollow thread, which becomes coiled as the nematocysts discharges. As the pattern is of the discharge is unknown, it appears to involve increases in capsule pressure upon release. Evidence exists that discharge begins as the jellyfish triggers an electrical signal caused from the transportation of stimuli received at the jellyfish’s tentacles. However, some researchers believe nematocyst independent effector hypothesis, excitatory and inhibitory neuronal input appears to regulate discharge.
