scholarly journals Role of Solvent Polarity on Dispersion Quality and Stability of Functionalized Carbon Nanotubes

2022 ◽  
Vol 6 (1) ◽  
pp. 26
Author(s):  
Dhivakar Rajendran ◽  
Rajarajan Ramalingame ◽  
Anurag Adiraju ◽  
Hanen Nouri ◽  
Olfa Kanoun
Keyword(s):  
Carbon Nanotubes ◽  
Visual Analysis ◽  
Electrochemical Impedance ◽  
Solvent Polarity ◽  
Cooh Group ◽  
Full Potential ◽  
Multiwalled Carbon ◽  
Vis Spectroscopy ◽  
Functionalized Multiwalled Carbon Nanotubes

Dispersion of carbon nanotubes (CNT) in solvents and/or polymers is essential to reach the full potential of the CNTs in nanocomposite materials. Dispersion of CNTs is especially challenging due to the van-der-Waals attraction forces between the CNTs, which let them tend to re-bundle and/or re-aggregate. This paper presents a brief analysis of the quality and stability of functionalized multiwalled carbon nanotubes (fMWCNT) dispersion on polar solvents. A comparative study of functionalized CNT dispersion in water, methyl, and alcohol-based organic solvents has been carried out and the dispersion has been characterized by UV-VIS spectroscopy, electrochemical characterization such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Visual analysis of the dispersion has been investigated for up to 14 days to assess the dispersion’s stability. Based on the material characterization, it was observed that the degree of affinity fMWCNT with -COOH group highly depends on the polarity of the solvent, where the higher the polarity, the better the interaction of fMWCNT with solvents.

UNUSUAL ELECTROCHEMICAL RESPONSE OF ELECTROCHEMICAL ETCHING ON MULTIWALLED CARBON NANOTUBES

NANO ◽  
2008 ◽  
Vol 03 (06) ◽  
pp. 461-467 ◽  
Author(s):  
JIAN-SHAN YE ◽  
GUANGQUAN MO ◽  
WEI DE ZHANG ◽  
XIAO LIU ◽  
FWU-SHAN SHEU
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Electrochemical Impedance ◽  
Electrochemical Etching ◽  
Current Response ◽  
Multiwalled Carbon ◽  
Transmission Electron ◽  
Oxidation Of Glucose ◽  
Total Disappearance ◽  
Electrocatalytic Effects

Multiwalled carbon nanotubes (MWNTs) can be etched at potentials more positive than 1.7 V versus Ag / AgCl (3 M KCl ) in 0.2 M HNO 3. The electrochemically etched MWNTs show an increase in electrochemical impedance and sluggish electron transfer kinetics, and lose the electrocatalytic effects toward the oxidation of glucose, H 2 O 2, uric acid (UA) and L-ascorbic acid (L-AA). Transmission electron microscope (TEM) images reveal that the nanotube tips are cut off by electrochemical oxidation. This may lead to the degradation of electrocatalytic ability in the MWNTs. Furthermore, the current response after different electrochemically etched cycles shows that the electrocatalytic ability of the MWNTs toward different molecules can be tuned by etched cycles. For example, five etched cycles leads to the total disappearance of the oxidative response to L-AA, with the remaining over 50% of the UA current response in the L-AA and UA mixture. Thus, electrochemical etching is a simple yet novel way to tune the electrocatalytic reactivity and improve the selectivity of the MWNTs.

scholarly journals Sorption and Desorption Analysis of Nitrobenzene on Differently Functionalized Multiwalled Carbon Nanotubes and Implications on the Stability

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1426
Author(s):  
Zhanhua Ji ◽  
Dengyu Li
Keyword(s):  
Carbon Nanotubes ◽  
Underlying Mechanism ◽  
Multiwalled Carbon ◽  
Environmental Behaviors ◽  
Initial Concentration ◽  
Sorption Hysteresis ◽  
Key Factor ◽  
Functionalized Multiwalled Carbon Nanotubes ◽  
The Stability ◽  
Adsorption Desorption

The stability of carbon nanotubes (CNTs) suspension is a key factor in determining their transport, fate, and toxicity in an aquatic environment, which is significantly influenced by CNTs’ nature and water chemistry. Macromolecular dissolved organic matter (DOM) is reported to influence the stability of CNTs aggregation. However, little is known on small polar dissolved organic compound’s effects on CNTs aggregation. Nitrobenzene was selected to investigate its interaction with three different functionalized multiwalled CNTs (MWCNTs). Both the stability of CNTs aggregation and sorption hysteresis were affected by the initial concentration of nitrobenzene and the surface functionalization coverage of MWCNTs. At the initial concentration below 580 mg/L, the thermodynamic index of irreversibility (TII) and turbidity of CNTs suspension had the same tendency, indicating that the underlying mechanism is closely related. A conceptual adsorption–desorption model was proposed to further explain the relationship between the sorption hysteresis and stability of MWCNTs suspension under different initial concentrations of nitrobenzene. This provided data support to further clarify the environmental behaviors and risks of CNTs.

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