Photonic crystals in biology

C
C
Poster Session, Tuesday, June 15
Theme A1 - B702
Synthesis of Multiwalled Carbon Nanotube/Polyphosphazene Nanocomposites
Elif Okutan 1* , Gülah Ozan 1 , Ferda Hacveliolu 1 , Saadet Kayiran Beyaz 2 , Serkan Yeilot 1 , Adem Klç 1
1 Kocaeli University, Faculty of Science and Arts, Department of Chemistry, 41380 Izmit- TURKEY.
2 Gebze Institute of Technology, Department of Chemistry, 41400 Gebze Kocaeli-TURKEY
Abstract— For improving the solubility of carbon nanotubes (CNTs) through chemical grafting both academic and commercial
organs have focused on. For this purpose remarkable effort has been devoted to the attachment of polymers to the nanotube surface, as
macromolecules can be much more effective in modifiying nanotube solubility properties than small molecules. This report demonstrates
simple and highly effective non-covalent method for the preparation of soluble MWCNT/poly-(4-pyridineoxy)(phenoxy)-
polyphosphazene nanocomposites.
Since their discovery the area of research focused on the
properties and the applications of CNTs [1]. However for the
wide applications of CNTs in industry the major problem is
still their poor wettability and dispersibility because of their
dewetting surface which waters down their great potential [2].
Coat them with a polymer through covalent or noncovalent
surface modification is a general strategy to overcome this
difficulty [3]. Interestingly CNT/polymer composites could be
tougher and more stratch-resistant than any other materials [4].
Polyphosphazenes (PDCP) have a flexible backbone of
alternating phosphorus and nitrogen atoms [5]. These
molecules can have wide range of physicochemical properties
and also their hydrophobic and hydrophilic balance can be
controlled by variation of side groups.
Our research area concerns the synthesis of carbon
nanotubes by CVD (chemical vapour deposition) method and
their organic or inorganic functionalization. Synthesis of
polyphosphazene derivatives and the synthesis of
nanotube/polyphosphazene (MWCNT/PZS) nanocomposites
in order to enhance dispersibility of the molecules in solvents
present also the goal of our researches.
In this study carbon nanotubes were synthesized by CVD
method and carboxylic acid functionalized MWCNTs (f-
MWCNTs) have been obtained by treatment of concentrated
H 2 SO 4 /HNO 3 (v:v, 3:1). PDCP has been synthesized via ring
opening polymerization of hexachlorocyclotriphosphazene.
Pyridineoxy and phenoxy substituted polyphosphazene (PZS)
has been obtained by the reaction of sodium salts of 4-
hydroxypyridinoxy and phenoxy with PDCP. A simple
pathway has been applied for the non-covalent side-wall
modification of f-MWCNTs using PZSs (Figure 1). The
MWCNT/PZS nanocomposite was characterized by FTIR,
Raman, SEM, HRTEM, 31 P NMR, 1 H NMR and TGA
methods.
Cl
P Cl
250
N N
o C
Cl Cl
P P
Cl N
Cl
O
P N
O n
Cl
P N
Cl
f-MWCNT, TEA
ultrasonication
n
OH
NaH, THF
N Cl
H
Figure 1. Schematic formation mechanism of the f MWCNT/PZS
,
OH
N
O
P N
O
N
n
HO
O
HO
O C
:
OH
OH
O C
O
P N
O
N
H
OH
O
C O C O
: f - MWCNT
OH
Cl
n
The core shell structures of f-MWCNT/PZS nanocomposites
were visible by HRTEM. As shown in Figure 2(A,B), the PZS
shell and the f-MWCNT graphite sheet structures are clearly
observed. The MWCNT diameter is measured as xxxxnm, and
the internal diameter is about xxx nm. Typical PZSs were
covered the MWCNT surface uniformly with shell thickness
in the range of 3.3-4.7 nm and the lengths of several
micrometers.
Figure2. Typical HR-TEM images of f-MWCNT/PZS nanocomposite at a
scale of 50 nm (A), and 5 nm (B)
Other characterization methods have demonstrated that the
MWCNTs are well functionalized without deterioration of
structure. The structure of the composite material is clarified
by the NMR measurements.
In conclusion, we have succeeded in evenly coating lineer
type polyphosphazene derivative onto the f-MWCNT surface.
This strategy is expected to beat a path to functionalizing
CNTs and prepearing new MWCNT-PZS nanocomposites.
The polyphosphazene having aromatic moieties and
quaternary nitrogen atoms in pyridine ring made f-MWNTs
soluble in solvents. Synthetic advantages of PZSs make them a
promising candidate for an advanced dispersing agent of
carbon nanotubes.
This work was partially supported by TUBITAK under
Grant No. 106T502 109T619.
*Corresponding Author: eokutan@gyte.edu.tr
A
[1] Iijima, S. , Nature 354, 56–58 (1991).
[2] Gao, C., He, H., Zhou, L., Zheng, X., Zhang, Y., Chem Mater. 21, 360-370
(2009)
[3] D. Tasis, N. Tagmatarchis, A. Bianco and M. Prato, Chem. Rev. 106, 1105
(2006)
[4] Ajayan, P. M., Zhou, O. Z., Top. Appl. Phys. 80, 391 (2001)
[5] Allcock H. R. Chemistry and Applications of Ployphosphazenes (John
Wiley&Sons. Hoboken, NJ, 2003
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6th Nanoscience and Nanotechnology Conference, zmir, 2010 363