Track‐Etching

Abstract

Track‐etch membranes (TMs) are produced by irradiating polymer films with highly ionizing particles followed by chemical etching. They differ from most conventional polymeric membranes because of their precisely controlled structure. Their pore size, shape, and density can be varied in a controllable manner to produce membranes with the required retention and transport properties. Polymer films are irradiated with either fission fragments or accelerated ions to form the so‐called latent tracks. The process of track etching then converts the latent tracks into hollow channels. Different etching methods have been developed that allow for the formation of cylindrical, conical, funnel‐like, cigar‐like, and other shapes of track‐etched pores. Commercial TMs are produced from polycarbonate, polyethylene terephthalate and polyimide, and their basic properties are presented in this article. TMs are used for diverse applications such as precise filters, model capillary systems, porous substrates, and templates for the synthesis of micro‐ and nanostructured materials.

Thermally stable nanoporous cyanate ester resin/linear polyurethane hybrid networks created by nuclear technologies

“…Pioneering studies of Fleischer and co-authors on track etching in thin sheets of materials [1,2] exploded a huge trend in further development of physics and chemistry of porous polymer materials, namely the generation of novel track-etched membranes (TMs), also known as Nuclepore membranes [3][4][5].…”

“…Nowadays, track-etching technology is extensively used in industrial scale for producing multipurpose polymer-based membranes for micro-and ultrafiltration, gas and liquid separation, water purification [3][4][5][6][7], in the areas of medicine, biotechnology and genetics [8].…”

“…During further etching of the irradiated films with solutions of alkalis, acids, oxidants and other chemical reagents, the fragments of the materials are washed out from the tracks and regular through pores are formed [3][4][5][6][7][8][9][10][11][12][13][14][15]. To generate track-etched membranes based on the most known polymers, the etching process usually does not exceed 30−90 min.…”

“…To generate track-etched membranes based on the most known polymers, the etching process usually does not exceed 30−90 min. The resulting TMs are characterized by an extremely regular porous structures with well-defined pore size, pore shape and density, ensuring the required controllable transport and retention characteristics [4,5,[15][16][17]. Moreover, the nuclear technology developed is quite universal and can be widely applied to most polymers and polymer blends [3][4][5][6][7][8].…”

“…To change pore size and shape, pore size distribution, and correspondingly, final permeability of the membrane produced, an additional sensitization of the irradiated film can be fulfilled, prior to etching. Sensitization is carried out through exposure to ultraviolet, plasma or γ-irradiation, additional temperature treatment, etc., thus resulting in increasing defectiveness of macromolecules and growth of the etching rate inside the tracks formed [3][4][5]13]. Usually, the preliminary sensitization procedure allows for improving pore shape and pore size distribution, increasing permeability coefficient along with easing etching conditions (decreasing etching temperature and duration, concentration of etching solution, etc.)…”