Bench-Top Method for Fabricating Glass-Sealed Nanodisk Electrodes, Glass Nanopore Electrodes, and Glass Nanopore Membranes of Controlled Size

Abstract

A simple benchtop method of fabricating glass-sealed nanometer-sized Au and Pt disk electrodes, glass nanopore electrodes, and glass nanopore membranes is reported. The synthesis of all three structures is initiated by sealing the tips of electrochemically sharpened Au and Pt microwires into glass membranes at the end of a soda lime or lead glass capillary. Pt and Au nanodisk electrodes are obtained by hand polishing using a high-input impedance metal oxide semiconductor field effect transistor (MOSFET)-based circuit to monitor the radius of the metal disk. Proper biasing of the MOSFET circuit, based on a numerical analysis of the polishing circuit impedance, allows for the reproducible fabrication of Pt disk electrodes of radii as small as 10 nm. Significantly smaller background currents in voltammetric measurements are obtained using lead glass capillaries, a consequence of the lower mobility of Pb(2+) (relative to Na(+)) in the glass matrix. Glass nanopore electrodes and glass nanopore membranes are fabricated, respectively, by removal of part or all of the metal sealed in the glass membranes. The nanostructures are characterized by atomic force microscopy, steady-state voltammetry, and ion conductivity measurements.

Electrochemistry at Nanoscale Electrodes: Individual Single-Walled Carbon Nanotubes (SWNTs) and SWNT-Templated Metal Nanowires

“…4,7 The most popular NSEs are based on tapered or etched metal wires encapsulated by a variety means to produce disk or conical electrodes. 2,[8][9][10][11][12] While attractive in principle, the accuracy with which these NSEs can be used depends on microscopy characterization of the electrode geometry.…”

“…4,7 The most popular NSEs are based on tapered or etched metal wires encapsulated by a variety means to produce disk or conical electrodes. 2,[8][9][10][11][12] While attractive in principle, the accuracy with which these NSEs can be used depends on microscopy characterization of the electrode geometry.This has often proved difficult due to the nanoscale dimensions of the electrodes, the presence of a large insulating coating and the fact that they do not reside on a planar substrate. In these instances, NSE dimensions tend to be estimated from limiting current measurements, but this may not inform on the precise electrode geometry or dimensions.…”

Métodos para fabricação de microeletrodos visando a detecção em microambientes

“…Os eletrodos foram conectados a um gerador AC (60 Hz) (custo R$ 5,00 a 10,00) de valor eficaz igual a 5 V, dispensando-se o uso de equipamentos mais caros e sofisticados (programador universal acoplado a um potenciostato-galvanostato ou geradores de função 70 ). O final do processo de corrosão ocorre quando a fibra se rompe na solução de CaCl 2 e acetona (15-16 min após o inicio do processo), formando-se então duas extremidades "apontadas", ao invés de somente uma como nos procedimentos anteriormente descritos.…”

“…Microeletrodos de poro em vidro 70,[129][130][131] podem ser fabricados a partir do desgaste eletroquímico de fibras metálicas encapsuladas em vidro. O processo para fabricação desse tipo de microeletrodo está mostrado na Figura 8, sendo que o raio do poro pode variar de 5 nm a 1 µm.…”

Lability of nanoparticulate metal complexes in electrochemical speciation analysis

“…The emergence of nano-sized electrodes in recent years [40,[42][43][44][45] generates the situation in which the reactive interface is more comparable in size to many NPs. That is, the spatial scale over which there is a concentration gradient in the surrounding medium will be comparable to or smaller than the particle body.…”