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DE LA FACULTAD DE INGENIERÍA
REVISTA TÉCNICAREVISTA TÉCNICA
Patrimonio del Estado Zulia e
interés Cultural desde 2001
Fecha de Construcción:
1954-1958
Diseño: Arquitecto Carlos Raúl
Villanueva, con elementos
novedosos de adaptación
climática.
Policromía de la obra: Artista
Zuliano Victor Valera.
VOL.42 ENERO - ABRIL 2019 No.1
Rev. Téc. Ing. Univ. Zulia. Vol. 42, No. 1, 2019, Enero-Abril, pp. 03-47
Rev. Téc. Ing. Univ. Zulia. Vol. 42, No. 1, 34-38, 2019
Scanning Electrochemical Microscopy: Methodology for
Construction of Ultramicroelectrodes with an Automatic
Micropipette Extruder
G. Zambrano-Rengel1,2,3* ,L. Dzib2,3 , D. Arceo2,3 , J. González2,3
1 CONACyT-Centro de Investigación en Corrosión, Universidad Autónoma de Campeche, Campus 6 de
Investigaciones. San Francisco de Campeche, Campeche, CP: 24070, México.
2 Centro de Investigación en Corrosión, Universidad Autónoma de Campeche, Campus 6 de Investigaciones.
San Francisco de Campeche, Campeche, CP: 24070, México.
3 Laboratorio Nacional de Ciencias para la Investigación y Conservación del Patrimonio Cultural LANCIC-
CICORR, Universidad Autónoma de Campeche, Campus 6 de Investigaciones. San Francisco de Campeche,
Campeche, C.P: 24070, México.
*Autor de Contacto: gezambra@uacam.mx, gezambranore@conacyt.mx
https://doi.org/10.22209/rt.v42n1a05
Recepción: 24/01/2018 | Aceptación: 15/10/2018 | Publicación: 15/12/2018
Abstract
Nowadays, in the Corrosion Research Centre (CICORR) of the Autonomous University of Campeche, an
electrochemical characterization route is being developed using the Electrochemical Scanning Microscopy technique
(SECM). It is been used on different systems oriented to the study of localized corrosion. This requires the construction
of the ultramicroelectrodes (UME); which are essential instruments for the technique application; through which is
possible to study high resolution electrochemical processes in the interface of a substrate in solution; by visualizing the
programmed minimizing errors for the required purposes. Subsequently, the properly manufactured instruments are
subjected to the respective calibration process.
Keywords: Ultramicroelectrodes, SECM, Localized Corrosion.
Microscopía Electroquímica de Barrido: Metodología para
la Construcción de Ultramicroelectrodos con un Extrusor
Automático de Micropipetas
Resumen
Actualmente, en el Centro de Investigación de la Corrosión (CICORR), de la Universidad Autónoma de Campeche,
se está desarrollando una ruta de caracterización electroquímica utilizando la técnica de Microscopía Electroquímica de
ultramicroelectrodos (UME); instrumentos fundamentales para la aplicación de la técnica a través de la cual es posible
estudiar procesos electroquímicos de alta resolución en la interfaz de un sustrato en solución, visualizando la electroquímica
fabricados se someten al proceso de calibración respectivo.
Palabras clave: Ultramicroelectrodos, SECM, Corrosión Localizada.
Rev. Téc. Ing. Univ. Zulia. Vol. 42, No. 1, 2019, Enero-Abril, pp. 03-47
35Scanning Electrochemical Microscopy : Methodology for Construction of Ultramicroelectrodes
Introduction
The scanning electrochemical miscroscopy
(SECM) technique allows the study in high resolution
of the electrochemical processes that occur at
visualizing the electrochemistry of topographies and
ultramicroelectrodes (UME), topographic sweep scan
probes previously constructed, are used. The procedure
is based on small movements of the tip thereof under
potentiostatic or potentiodynamic operation [1]. The
ultramicroelectrodes (UME) can have ion-selective tips
according to the required purposes and can detect the
reactions that occur in close proximity to the studied
surface, obtaining images of chemical reactivity thereof
and quantitative measurements of the reaction rates [2-3].
The complete electrochemical equipment
consists of a digital signal generator/plotter computer
with the integrated CHI 12.26 software, three-dimensional
movement piezoelectric/nano-positioner, with maximum
spacing distance of 50 mm; a bipotentiostat/galvanostat
with data acquisition circuits of high resolution, range of ±
10 mV and ±250 mA up to the order of the picometers; and
a three-electrode measuring cell [3].
The goal is the construction of ultramicroelectrodes
through an automated process, using an automatic
micropipette extruder; whih is generally employed for
the micropipettes construction with medical or biological
uses; reprogramming the equipment for the required
purposes.
Experimental Section
Automatic Micropipette Extruder Sutter Instrument
P-1000
As a fundamental step for the technique
development, the ultramicroelectrodes (UME) must be
designed and manufactured [2-3]. The construction
involves the manufacturing of a glass scanning probe
in a fast and systematized way, using an automatic
Sutter Instrument P-1000 micropipette extruder
[4]. The equipment performance is focused on the
ultramicroelectrodes construction (UME) used in
electrochemical measurements by the scanning
electrochemical microscopy technique (SECM). The
on this, the equipment is programmed minimizing
errors for the required purposes through a color touch
screen that provides an intuitive interface and has a
library of previously loaded programs and the option of
programming new instructions for the construction of
micropipettes, quickly and automatically.
Ultramicroelectrodes and Scanning Electrochemical
Microscopy, CH Instruments CHI920C
The performance of the CHI 12.26 software
associated with the operation of the scanning
electrochemical microscope is tested through a dummy cell
selecting a potential range of 0.5 V to -0.5 V with a series
menu. Subsequently, a piezoelectric/nano-positioner is
calibrated with an installed ultramicroelectrode (UME)
previously manufactured, immersed in a solution of 1 mM
ferrocemethanol plus 0.1 M KNO3. This compound is soluble
in water, has a reversible redox reaction with reproducible
data and does not contaminate the microelectrodes tip.
and is inserted into the electrochemical microcell of the
scanning electrochemical microscope. A saline bridge, a
counter electrode and the Ag/AgCl reference electrode
The ultramicroelectrode tip (UME) is positioned close
to the substrate surface with help of the XYZ movement
command from the software options menu, avoiding the
impact and breaking of the ultamicroelectrode tip on the
metal surface (Figure 1). When the tip is fairly close to
the surface, cyclic voltammetry curves are obtained to
characterize the recorded potential values at both, the
ultramicroelectrode tip and the test substrate. These
data are used as base for subsequent generation of the
Approach Curves (PAC) [5].
Figure 1. Scanning electrochemical microscopy CH
Instruments CHI920C. Scheme of the experimental
device for scanning electrochemical microscopy.
Rev. Téc. Ing. Univ. Zulia. Vol. 42, No. 1, 2019, Enero-Abril, pp. 03-47
36 Zambrano y col.
Results and Discussion AA DUCT 2979. Subsequently, properly manufactured
ultramicroelectrodes are subjected to a review and
calibration process. Figure 2 shows the scanning electron
microscopy micrographs of micropipettes characteristics
for ultramicoelectrodes, manufactured automatically
with the Sutter Instrument Model P-1000. The images
were taken with a Scanning Electron Microscope
Hitachi FlexSEM 1000, at accelerating voltage 5 kV and
A)
B)
Figure 2. Scanning Electron Microscope micrograph of
a micropipette with: A) Short cones, thin and elongated
and wide tips, thin borosilicate glass, high resistance.
tips are those that have a cone shape with high mechanical
resistance which allows the micro-electrode interacting
propperly with the substrate during the electric current
application by the bi-potentiostat. As well, Figure 3
ultramicroelectrodes samples.
Extruder Sutter´s Calibration
The extruder calibration consists in determining
the ramp temperature. The breaking of the borosilicate
glass capillary introduced into the heating jaw of
the equipment will be reached. This temperature
guarantees a clean and fast capillary breakage after a few
seconds. The ultramicroelectrodes with more resistant
cones were obtained at 525°C ramp temperature.
Ultramicroelectrodes (UME) Construction
The characteristics of the used borosilicate glass
pieces are 4± 0.125 cm in length, with internal diameter of
1± mm and external diameter of 2±0.05 cm, King Precision
introduced. A 4 mm2 square heating jaw is installed into
the equipment as a resistance for heat transfer. A piece
of glass is positioned and aligned in the center of the jaw,
supported horizontally by special screws. Subsequently, it
is inserted through it. The chamber humidity is controlled
and determined if the capillary is correctly aligned from
left to right. For the software equipment, the necessary
available for use, minimizing errors and simplifying the
equipment programming for the required purposes. Later,
use, minimizing errors and simplifying the equipment
programming for the required purposes. If the pre-
for automatic programming could be determined based
on trial and error tests, until the necessary pipettes are
obtained. An interactive screen is programmed with the
previously determined parameters. These parameters
must be the heat of the jaw or ramp temperature (°C),
pushing force (pull), rate or velocity (units/ms), pressure
(psi), waiting time or delay for the separation (ms),
capillaries characteristics and used glass type. When
the equipment has been calibrated and all the necessary
parameters has been programmed, the micropipettes
can be produced. Immediately, after several cycles of
heat and force application, the glass can be separated
in two identical pipettes, which will potentially be
ultramicroelectrodes (UME) used for characterization
with scanning electrochemical microscopy (SECM). The
silver conductive epoxy resin, Atom Adhesive brand, model
Rev. Téc. Ing. Univ. Zulia. Vol. 42, No. 1, 2019, Enero-Abril, pp. 03-47
37Scanning Electrochemical Microscopy : Methodology for Construction of Ultramicroelectrodes
Figure 3. Ultramicroelectrodes (UME) manufactured automatically with the equipment
Sutter Instrument Model P-1000.
When the piezoelectric/nano-positioner
is calibrated with one of the manufactured
ultramicroelectrodes (UME) previously installed, the
maximum distance between the ultramicroelectrode tip
and the interface of the studied substrate, conductor or
insulator is determined [5, 6-7]. The tip is approached
at the correct distance and the Surface Scanning Curves
(PSC) are carried out, determining the boundary between
the insulator and the conductor, obtaining border images.
Ultramicroelectrodes (UME) Calibration
Figure 4 shows one of the calibration curves
obtained from a platinum ultramicroelectrode (UME) in a
solution of 1 mM ferrocemethanol plus 0.1 M KNO3. The
values of the current response (A) from both; the tip of the
ultramicroelecrode (UME) and the conductor substrate;
are obtained. The data are used, subsequently to obtain the
electrode. A straight line with soft slope must be obtained in
the case of a propperly manufactured ultramicro-electrode.
Figure 5 shows the maximum approximation
curves of the ultramicroelectrode (UME) obtained from
a conductive substrate and a non-conductive substrate
[3-4,
characterizations with scanning electrochemical
microscopy (SECM).
Figure 4. Ultramicroelectrode (UME) calibration curve
for platinum, ferrocemethanol 1 mM + 0,1 M KNO3
solution.
A)
Figure 5. Approximation curve for platinum on A)
Rev. Téc. Ing. Univ. Zulia. Vol. 42, No. 1, 2019, Enero-Abril, pp. 03-47
38 Zambrano y col.
Conclusions
The construction of ultramicoelectrodes (UME)
through a well-established and controlled elegant
methodology allows the application of the technique to
study the red-ox reactions and faradaic phenomena on
metals surfaces with controlled resolution which can be
improved up to a nanometric range.
The micropipettes with more resistant cones
were obtained at 525°C ramp temperature, with a speed
between 16-18 units/ms, without pushing force, 500 psi
pressure and waiting time for the separation 1 ms.
Acknowledgments
G. Zambrano-Rengel expresses her gratitude for
the support given by the CONACyT and the “CÁTEDRAS”
for Young Researchers Program; and also the Project
Infrastructure 2016; important supports for the
“Corrosion Sciences and Engineering” consolidated group,
CIC-Corrosion Research Center, to which she was
assigned. Thanks to “National Laboratory of Sciences for
Research and Conservation of National Heritag”, LANCIC-
CICORR, Project No. 279740, for the help received for
characterization analysis.
References
[1] Sun P., Laforge F.O. and Mirkin M.V.: “Scanning
electrochemical microscopy in the 21st century”.
Phys. Chem. Chem. Phys., Vol. 9 (2007) 802–823.
[2]
studies in microsystems”. Electrochimi. Acta, Vol. 47
(2001) 191-199.
[3]
electrochemical microscopy. Introduction and
principles”. Anal. Chem., Vol. 61 (1989) 132-138.
[4] Oesterle A.: “The Pipette Cookbook, P-97 & P-1000
Micropipette Pullers Manual”. Sutter Instrument
Company, Novato CA, 2015.
[5]
electrochemical microscopy (SECM): an
investigation of the effects of tip geometry on
102, No. 49 (1998) 9946-9951.
[6]
D.: “Scanning electrochemical microscopy: a new
of surfaces”. Acc. Chem. Res., Vol. 23 (1990) 357-
363.
[7]
Schuhmann W.: “Constant-distance mode scanning
electrochemical microscopy. Part II: high-resolution
SECM imaging employing Pt nanoelectrodes as
miniaturized scanning probes”. Electroanalysis, Vol.
16, No. 1-2 (2004) 60-65.
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