Chemistry Reference
In-Depth Information
Properties and characterization
Wang et al. [99] represented that morphology and mechanical properties of CS has
promoted by adding CNTs. Beside, Zheng et al. [134] proved that conducting direct
electron is very useful for adsorption of hemoglobin in CNT/CS composite film. These
studies have been demonstrated that this nano-biocomposite can used in many field
such as biosensing and biofuel cell approaches.
Tang et al. [135] evaluated water transport behavior of CS porous membranes
containing MWNTs. They characterized two nanotube composites with low molecular
weight CSP6K and high molecular weight CSP10K. Because of hollow nano-channel
of MWNTs located among the pore network of CS membrane, the water transport
results for CSP6K enhanced, when the MWNTs content is over a critical content. But,
for CSP10K series membranes, the water transport rate decreased with increase of
MWNTs content due to the strong compatibility effect of MWNTs.
In another attempts, the CNT/CS nanocomposites were prepared by utilizing
poly(styrene sulfonic acid)-modifi ed CNTs [136]. Thermal, mechanical, and electrical
properties of CNT/CS composite fi lm prepared by solution-casting showed potential
applications for membranes and sensor electrodes.
Novel approaches
In a new approach, MWNT functionalized with--COOH groups at the end or at the
sidewall defects of nanotubes by CNTs in nitric acid solvent. The functionalized CNTs
immobilized into CS films by Emilian Ghica et al. [137]. This film applied in ampero-
metric enzyme biosensors, resulted glucose detection, and high sensitivity.
In a novel method, Kandimalla and Ju [138] cross-linked CS with free--CHO
groups by glutaraldehyde and then MWNTs added to the mixture. The cross-linked
MWNT-CS composite immobilized acetylcholinesterase (AChE) for detecting of both
acetylthiocholine and organophosphorous insecticides. On the other hand, Du et al.
[139] created a new method for cross linking of CS with carboxylated CNT. This new
method was performed by adding glutaraldehyde to MWNT/CS solution. They immo-
bilized AChE on the composite for preparing an amperometric acetylthiocholine sen-
sor. The suitable reproducible fabrication, rapid response, high sensitivity, and stability
could provide an amperometric detection of carbaryl and treazophos [140] pesticide.
Abdel Salam et al. [141] showed the removal of heavy metals including copper, zinc,
cadmium, and nickel ions from aqueous solution in MWNT/CS nanocomposite fi lm.
Surface deposition crosslink
Liu et al. [142] decorated CNT with CS by surface deposition and cross linking pro-
cess. In this new method, CS macromolecules as polymer cationic surfactants were
adsorbed on the surface of the CNTs. CS is able to produce stable dispersion of the
CNT in acidic aqueous solution. The pH value of the system was increased by am-
monia solution to become non-dissolvable of CS in aqueous media. Consequently,
the soluble CS deposited on the surface of CNTs similar to CS coating. Finally, the
surface-deposited CS was cross-linked to the CNTs by glutaraldehyde. They found
potential applications in biosensing, gene, and drug delivering for this composite.
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