Pore shape control in nanoporous particle track etched membrane

Template synthesis is a relatively simple and easy procedure which has made the fabrication of rather sophisticated nanomaterials accessible to almost any laboratory. Template synthesis requires access to instrumentation capable of metal sputtering and electrochemical deposition. The characterization of the fabricated nanostructures can be done using instrumental techniques including spectrophotometry, voltammetry, optical microscopy, atomic force microscopy, and electronic microscopies (scanning electron microscopy (SEM) and transmission electron microscopy (TEM)).The method is based on the simple but effective idea that the pores of a host material can be used as a template to direct the growth of new materials. Historically, template synthesis was introduced by Possin (1) and refined by Williams and Giordano (2) who prepared different metallic nanowires with widths as small as 10 nm within the pores of etched nuclear damaged tracks in mica. It was further developed by Martin's group (3-5) and followed by others (6) with the number of examples and applications (7) continually increasing. The nanoporous membranes usually employed as templates are alumina or track-etched polymeric membranes which are widely used as ultrafiltration membranes. Recently, metal nanostructures have also been obtained using the pores created by self-assembly in block copolymer structures under the influence of electric fields and high temperatures (8, 9).The first part of this section focuses on the main characteristics and fabrication techniques used for obtaining templating membranes and depositing metal nanostructures by suitable electroless and electrochemical procedures. Methods such as sol-gel (10-12) or chemical vapor deposition (10, 13), which have been used primarily for the template deposition of carbon, oxides, or semiconducting-based materials, will not be considered here in detail. The second part of the section focuses on the electrochemical properties of the fabricated nanomaterials with emphasis on the characteristics and applications of nanoelectrode ensembles (NEEs). Templating membranes 16.2.2

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“…It was shown that perfectly cylindrical pores could be obtained if a special PC film (PC ϩ ) is used instead of standard PC films (36).…”

Section: 3)mentioning

confidence: 99%

Template Deposition of Metals

Ugo

Moretto

2007

Handbook of Electrochemistry

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“…The corresponding diameter and length of pores and synthesized microwires are similar for the reason that embedded pores within TEM template act as excellent moulds (Chakarvarti and Vetter, 1998;Enculescu, 2006;Chakarvarti, 2009). As far as the segment to segment and wire to wire variation is concerned, the same is understood to be negligible in conjunction with least variation of morphology and alignment of pores achieved by controlling homogeneity of the incident ion beam, target material and etching conditions while preparing the TEMs which is a well established distinct feature of ion track etch technique (Apel, 2001;Ferain and Legras, 2001;Nikezic and Yu, 2004;Sartowska et al, 2012;Kumar and Chakarvarti, 2006). The standard deviation is significantly small due to narrow pore size distribution that is a function of pore density nearly equal to flux density of irradiated ion beam which is 10 6 ions/m 2 in the present work.…”

Section: Resultsmentioning

confidence: 98%

“…The shape of the pores can be tailored cylindrical, conical, double conical and funnel-like under controlled etching conditions. Density and orientation of pores depend on the collimation of ion beam during irradiation process (Ferain and Legras, 2001;Apel, 2001;Apel, et al, 2001;Karim et al, 2009;Garg et al, 2012;Quinn et al, 1972). The development of controlled and predictable pores in TEMs has already been achieved in research to supply accurate membranes apt to the template assisted synthesis of geometrically known micro/nanostructures.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Microwires of Polypyrrole via Chemical Polymerization using Track Etch Membrane as Template

Garg¹,

Kumar²,

Chakarvarti³

2014

AJMST

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Low dimensional structures of conducting polymers, particularly polypyrrole, have attracted a great attention of researchers and engineers in recent years because of their diverse potential application on account of their unique properties of large aspect ratio, good electrical conductivity, environmental stability and biocompatibility. The present work describes synthesis of polypyrolle microwires by template assisted chemical polymerization at room temperature using FeCl3 as an oxidant. In this technique, the track etch membrane used as a template was fitted between two chambers in a chemical cell in such a way that the template acts as a separating wall between the chambers. One chamber was filled with an aqueous monomer pyrrole solution and other was filled with oxidant reagent of ferric chloride. Chemical polymerization takes place within the pores of the template as the monomer and the oxidant reagent diffuse towards each other, react to yield the conductive polymer which grows as microstructure in the shape of pores of host template. Synthesized samples have been characterized by Scanning Electron Microscopy (SEM), which reveals that the morphology of the microwires matches with the morphology of pores as mould in host template. Diameter, orientation and direction of growth of microwires were almost uniform because of the confined growth of microwires in the ordered and symmetric pores of TEM template. Conductivity of polypyrrole microwires was estimated equal 20.152 S/m form current-voltage characteristics measured using a two-probe-method.

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“…Two different types of templates are commonly used in the art, namely the ion-track etched (TE) polymers and the anodic porous alumina membranes. Although both membrane types can provide nanochannels tailored to a given diameter, their nature and morphology present some important differences influencing the filling process and, therefore, they must be considered with particular attention (Ohgai et al, 2003;Schönenberger et al, 1997;Ferain & Legras, 2001;Pullini et al, 2007a). Even though it is commonly acknowledged from an industrialization standpoint that TPED is a cost-effective technique and easily scalable, mainly due to a wide plurality of factors affecting the nanowire growth, there are still contradicting process details in the published literature which make the technology not ready yet to be scaled up.…”

Section: Process Mastering For Tailoring Growthmentioning

confidence: 99%