Photonic crystals in biology

Poster Session, Tuesday, June 15
Theme A1 - B702
Preparat ion of ZnO-CeO 2 ceramic nanofibers via a n electros pinning technique
Didem Tascioglu 1 , Nesrin Horzu m Polat 1 , Mustafa M. Demir 1 *
Department
1
Abstract-Mixed metal oxide fibers based on cerium oxide and zinc oxide were produced by combination of electrospinning and calcination
processes.
Porous ceramic materials are attractive materials that have
found applications in sensors [1], filtration [2], catalysts [3,
4], membrane and adsorption of liv ing cells for scaffolds in
tissue engineering [5]. There are various ways to produce
porous ceramic materials with high surface area; however,
electrospinning appears to be the most convenient method
among the others due to the following advantages. (i) high
surface area from per unit volume of polymer (ii) ease of
implementation. In a typical electrospinning process, a high
potential difference is applied to a polymer solution droplet
suspended at the tip of a needle of syringe. Charge is collects
on surface of this droplet, and as the electrical potential
overcomes the surface tension of the solution, the droplet
continues and forms a Taylor cone. The solution ejected from
the tip of the Taylor cone travels through the air to collector
screen and collects as nonwoven fibers.
This study is aimed to synthesize ZnO-CeO 2 ceramic
nanofibers via the electrospinning and calcination processes.
Counts/s
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(111)
(100)
(002)
(200)
(101)
(220)
(102)
(311)
(110)
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CeO 2
ZnO
(103)
(222)
2 theta
Figure 1. X-ray diffraction pattern of ZnO-CeO 2 composite
fibers containing the 2.5:1 molar ratio and reference patterns of
pure ZnO and CeO 2 .
Figure 1 indicates the X-ray diffraction pattern of
synthesized ZnO-CeO 2 ceramic nanofibers. All reflections
are matched well with the reference patterns of hexagonal
zinc oxide and face centered cubic ceria that means the
calcined fibers are mixture of ZnO-CeO 2 crystals.
Figure 2 presents SEM images of elecrospun fibers before
and after calcination process. The fibers initially contain
precursor salts (CeNO 3 ) 3 .6H 2 O and Zn(CH 3 COO) 2 .2H 2 O
and PVA. The diameter of fibers is in range of 100-175 nm.
Upon application of calcination process at 500 ºC, the
diameter is reduced to 40-85 nm most probably due to the
removal of polymeric component of the system. It has to be
mentined here that the morphology of fibers remain
unchanged, i.e. removal of organics does not lead to
undesirable shape change. The sensor application of the
resulting fibrous semiconductor material is ongoing.
(a)
(b)
Percentage
Percentage
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Fiber Diameter (nm)
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Calcination
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40 55 70 85 100 115 130 145 160 175
Fiber Diameter (nm)
Figure 2. SEM micrographs and diameter distributions for (a)
precursor fibers (the molar ratio of Zn:Ce is 2.5:1) (b) the
calcined at 500ºC.
*Corresponding author: mdemir@iyte.edu.tr
[1] Songa, X., and Liub, Li. 2009. Characterization of electrospun
ZnO–SnO 2 nanofibers for ethanol sensor. Sensors and Actuators A
154 (pp. 175–179).
[2] Yoon K., Kim K., Wang X. F., Fang D. F., Hsiao B.S., Chu B.
2006. High flux ultrafiltration membranes based on electrospun
nanofibrous PAN scaffolds and chitosan coating. Polymer, 47, (pp.
2434–2441).
[3] Demir M. M., Gulgun M. A., Menceloglu Y. Z.,Erman B.,
Abramchuk S. S., M akhaeva E. E. Khokhlov A. R., Matveeva V. G.,
Sulman M. G. 2004. Palladium nanoparticles by electrospinning
from poly(acrylonitrile-co-acrylic acid)-PdCl 2 solutions. Relations
between preparation conditions, particle size, and catalytic activity.
Macromolecules, 37, (pp. 1787–1792).
[4] Demir M. M., Ugur G., Gülgün M. A., Menceloglu Y.Z.
2008. Glycidyl-methacrylate-based electrospun mats and catalytic
silver nanoparticles. M acromolecular Chemistry and Physics, 209,
508–515.
[5] Nisbet D. R., Forsythe J. S., Shen W., Finkelstein D.I.,
Horne M. K. 2009. Review paper: A review of the cellular
response on electrospun nanofibers for tissue engineering. Journal
of Biomaterials Applications, 24,(pp. 7–29).
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6th Nanoscience and Nanotechnology Conference, zmir, 2010 329