Polyester track-etched

Polybenzimidazole (PBI) Polybenzlmldlazolone (PBIL) Polycarbonate (track-etched) Polyester (track-etched)... 

Table 1. Properties of Polyester Track-Etched (PETE) Membranes...

Fig. 18 Cyclic voltammograms of 1 mM TEA as obtained using rotating (a) baffle and (b) disk cells with 6 im-thick polyester track-etched membranes. Rotation frequencies are (1) 52, (2) 41, and (3) 10 rad/s. Reprinted with permission from ref. 86. Copyright 2002 American Chemical Society.

Finally, track-etched MF membranes are made from polymers, such as polycarbonate and polyester, wherein electrons are bombarded onto the polymeric surface. This bombardment results in sensitized tracks, where chemical bonds in the polymeric backbone are broken. Subsequently, the irradiated film is placed in an etching bath (such as a basic solution), in which the damaged polymer in the tracks is preferentially etched from the film, thereby forming cylindrical pores. The residence time in the irradiator determines pore density, and residence time in the etching bath determines pore size. Membranes made by this process generally have cylindrical pores with very narrow pore-size distribution, albeit with low overall porosity. Furthermore, there always is the risk of a double hit, i.e., the etched pore becomes wider and could result in particulate penetration. Such filter membranes are often used in the electronic industry to filter high-purity water. 

Track-etched polymer membranes, which have straight cylindrical pores that are oriented normal to the plane of the membrane, provide a promising platform to design membranes with nano-domains with high aspect ratios oriented in the desired direction. Presently, track-etched membranes are commercially available in polyester and polycarbonate with various thicknesses (6 pm or above), pore sizes (10 nm to microns), and porosities ( 0.05% to... 

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