“Track-etching” process is based on:

1. the beaming of a thin polymer film with energetic heavy ions, leading to the formation of linear damaged tracks all across the film,

followed by:

2. a selective chemical etching of these tracks into well-defined pores .

This process, adapted to a large scale industrial production, offers various benefits to the resulting track-etched membrane filters:

  • a homogeneous and accurate pore size;
  • a surface retention during filtration;
  • a wide range of mass and volumetric flow rates;
  • an easy handling and its availability in various formats.
track-etched membrane filters

Narrow filtration cut-off of a track-etched membrane filter (in green) compare to the feature of a depth filter (in red).

Accurate pore size from 0.01 µm to 30 µm

it4ip track-etched membranes filters feature a sharply defined cylindrical shape for all pore dimensions ranging from 10 nanometers to over 30 micrometers.

The physical mechanism at the base of the pores appearance intrinsically yields a narrow pore size distribution and providing sharp cut-off filters.

This outstanding shape and dimensional control enable efficient size exclusion of particles during any filtration process, this make them suited for the most demanding filtration operations, and also for more specific demands such as template for the synthesis of 1D nano- or micro-objects.

Surface retention

Because of the homogeneity of the pore size and of the pore shape created by the track-etching process, track-etched membrane filters used for filtration retain all particles larger than the pore size on their flat and smooth surface.  The retained particles are therefore easily recovered or easily detected and analysed by any appropriate detectors.

Compared to any traditional depth filters, track-etched membrane filters are characterised by a very low thickness suitable for high air and water flow rates.

track-etched membrane filters

Bacteria retained on the membrane surface after filtration of a sampling control through pores smaller than bacteria dimensions.

Flow ranges

Typical water and air flow ranges for standard track-etched membrane filters.

Porosity from less than 0.1 % to more than 40 %

Track-etching technology is most suitable for an independent control of both pore size and pore density: pore density is defined during the first step of the process while pore size is defined by etching conditions.

Current beaming conditions can be finely tuned to obtain a pore density ranging from 1,000 pores per square centimetre to more than 1E+09 pores per square centimetre.

Selection of pore size and of pore density, combined to the choice of filter thickness, enable the manufacturing of track-etched membrane filters characterise by a wide range of water and of air flows.

Easy handling and suitable for various cutting process

Track-etching process is generally suitable for polymer films with thickness from 50 microns down to 5 microns.

Technology is currently applied to polycarbonate (PC), polyester (PET) and polyimide (PI) films, providing following intrinsic properties to track-etched membrane filters: low extractable, low protein binding, negligible adsorption and absorption of filtrates to maximise critical solution recovery, biocompatibility, excellent chemical resistance and thermal stability.

Available in film format, track-etched membrane filters can be further processes to make them more appropriate to their applications (surface modification, dyeing, …).

They are also easily cut in reels or in lab-discs to ease their use or their combination with specific filtration devices.

polycarbonate (PC)

Polycarbonate (PC)

Polyester (PET)

Polyester (PET)

Polyimide (PI)