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Class: Introduction to the Nanoelectromechanical Systems
Date：2011/11/04
Name：梁詠翔 Long-Xiang, Liang
Teacher：Professor Hsu
Page 1
Outline
1. Abstract(摘要)
2.
3.
4.
5.
6.
7.
8.
ExperImental(實驗)
Dielectrophoretic(介電泳)
Automatic pencil lead as the electrode(鉛筆芯)
Note etching(蝕刻注意事項)
Automatic pencil for etching parameters(參數)
Experiment of results(實驗結果)
ConclusIons(結論)
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Abstract
1. A microelectrode was fabricated by electrochemical etching
of a pencil lead (0.5 mm in diameter) in 1.0 M NaOH
aqueous solution.
2. The pencil lead was dipped into the solution and then an ac
voltage (3.0 Vrms for10 min) was imposed against a
stainless plate under mild stirring (450 rpm).
3. The microelectrode was used to perform dielectrophoresis of
polystyrene latex microbeads (nominal diameter of 3 m) and
human red blood cells.
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ExperImental
Materials and chemicals
(詳細鉛筆芯微電極)
(隔熱層)
(微電極)
(鉛筆芯微電極)
(三立體定位)
(函數發生器)
(樣品)
(控制器)
(示波器)
(顯微鏡)
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Dielectrophoresis (DEP) refers to the
migration of dielectric particles under the
net force .
Dielectrophoretic ?
1.Device compared to optical tweezers
control more easily set up and sound
equipment need to rely on low cost
and high degree of experience with
complex procedures.
2. Designed according to the size of the
electrode can control the particle size
from sub-micron to tens of microns.
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Graphite pencil leads of 0.5 mm in diameter and 60 mm in length .
(Pentel C205 series of grade 4H, 2H, H, HB, 2B, 4B; and Pilot ENO
series of grade 4H, 2H, H, HB, 2B, 4B)
Why should application of automatic pencil lead as the
electrode ?
1.The composition ratio of carbon a high degree of control .
2. Pencil tough mechanical strength, unlike the hard glassy carbon electrode .
3. Cheap .
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Note
etchIng
(電源供應器)
(石墨鉛筆芯)
(不鏽鋼板)
Fig. Schematic diagram of the etching bath. Both graphite
pencil lead and stainless
plate were submerged into the solution with an angle of about 30◦
to avoid thebubbling effect.
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 Automatic pencil for
etching parameters
K2Cr2O7 Efficiency for the etching solution concentration .
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Experiment of results
1.
DEP latex particles
2.
DEP red blood cells
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Experiment of results
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ConclusIons
With a simple electrochemical etching process, our group has
successfully fabricated a graphite pencil lead microelectrode with
Its diameter approaching 10 um. The insulation for the
microelectrode was achieved by shielding with a polypropylene
layer.The low-cost microelectrode can be easily manufactured with
a reproducible quality and high analytical performance. Equipped
with a conductive glass as the counter electrode and the
microscopic window, a simple dielectrophoretic chamber was
designed using the mentioned microelectrode to generate an
asymmetrical electric field. The economic and simple system was
proven to be suitable for manipulating microparticles under direct
microscopic observation.
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Thank for your attention .
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