Standard thickness: manufactured from 25 µm thick PC film.
- polycarbonate (PC)
- low porosity transparent membranes for visualisation of live cells by light microscopy
- high porosity translucent membranes with high pore density for transport studies
- proprietary tissue culture (TC) surface treatment
- option for parallel pores or for crossed pores
- suitable for sterilization (gamma-rays)
- good chemical resistance (tables), biocompatibility and low protein binding
- maximum operating temperature: 140°C (284°F) for PC and PET membranes
We only use high quality materials providing their intrinsic properties to all track-etched membrane filters: low extractable, low protein binding, negligible adsorption and absorption, biocompatibility, excellent chemical resistance and thermal stability.
Available thicknesses for raw materials
Intrinsic properties of raw materials
Used polymer films provide their 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.
UNIFORM PORE SIZE BY TRACK-ETCHING
The physical mechanism at the base of the pores appearance during the track-etching process ensures a precise and uniform pore diameter, intrinsically yielding a narrow pore size distribution and providing sharp cut-off filters.
This outstanding shape and dimensional control enable efficient and accurate 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.
(left) Slightly tilted pictures of the surface of a track-etched membrane filter showing regular and homogenous pores (right) transversal cut showing straight and cylindrical pores crossing all the membrane filter thickness pore diameter = 0.4 micron (by scanning electronic microscopy)
WIDE RANGE OF POROSITIES AND FLOW RATES
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.
Air and water flow ranges – in L min-1 cm-2 @ 0.7 bar (10 PSI)
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.
Suitability for advanced pore structure
If common track-etched membrane filters are made of multi-angle pores, the flexibility of the beaming process enable us to achieve alternative porous structures.
SCREEN FILTERS IDEAL FOR ANALYSIS OF RETAINED PARTICLES
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.
Beaming of raw polymer films
Heavy ions are generated by a ion source and then accelerate by a cyclotron to energy as high as 4 MeV/uma.
For the beaming, the polymer film is unwounded at a constant speed under vacuum through the scanned ion beam ; the tracks density (or desired pore density) is therefore precisely defined by the ion beam intensity and the film velocity.
The film is pulled over a bending roll to increase the angular spread of the tracks, and thus raise the selectivity of the membrane filters by avoiding parallel double tracks.
Chemical etching of beamed polymer films
Linear tracks created during the beaming are mainly characterised by macromolecular chain scissions, highly hydrophilic chemical groups and free vacuum.
Tracks are therefore more sensitive to chemicals than surrounding bulk polymer, and can be selectively etched leading to their revelation into pores.
Chemical etching is commonly carried out with an aqueous alkaline solution at a well-controlled concentration and temperature. It is mainly characterised by the track etching rate (Vt) and the bulk etching rate (Vg). A high ratio Vt/Vg is needed to obtain an homogeneous membrane filter with cylindrical pores.
Pore size is defined by the etching conditions while pore density is defined by the beaming parameters. Pore size and pore density can be therefore independently
State of the art
State-of-the-art track-etching technology can be applied to polyimide (it4ip exclusivity), polyester and polycarbonate. Learn more about the specific features of our membranes.