Track etching thin film process, also known as ion track etching or particle track etching process, is a method of creating highly ordered nanoporous structures in polymer films by selectively etching ion tracks. technology. The technology has applications in various fields such as water filtration, biosensing and nanofluidics.
Process principle
The principle of the track etching thin film process involves irradiating the polymer thin film with heavy ions or charged particles, causing damage or latent tracks, making these tracks chemically sensitive areas, and at the same time, they can be selectively etched using a suitable etchant solution, Nanopores are thereby formed in the polymer film.
Process description
1. Preparation of polymer film, the process starts from the preparation of polymer film, which can be made of materials such as polyethylene terephthalate (PET), polycarbonate (PC) or polyimide (PI) made, film thickness can vary depending on the desired application.
2. Irradiation, followed by exposure of the polymer film to a beam of heavy ions (such as uranium or gold) or charged particles (such as protons or electrons). Exposure conditions such as ion energy, fluence, and angle can be controlled to achieve the desired track density and pore size distribution.
3. Chemical etching, after irradiation, immerse the polymer film in a suitable etching solution, which can be an aqueous solution of strong acid (such as hydrochloric acid) or strong alkali (such as sodium hydroxide). The etchant selectively dissolves the damage caused by the ions along their tracks, forming nanopores in the film. Pore size and shape can be controlled by adjusting etching time, temperature and concentration of etchant.
4. Post-processing, after etching, the nanoporous membrane is rinsed with deionized water and dried. The thin film can optionally be subjected to additional treatments, such as surface modification or pore size reduction, to tailor its properties for specific applications.
Etching materials and requirements
1. Using polymer film, commonly used materials for track etching include polyethylene terephthalate (PET), polycarbonate (PC), and polyimide (PI).
2. For the irradiation source, a suitable ion source or charged particle source, such as a cyclotron, tandem accelerator or electron beam generator, is required to irradiate the polymer film.
3. The choice of etching solution, use strong acid or strong alkali solution for etching, such as hydrochloric acid, sodium hydroxide, potassium hydroxide, etc.
4. Other equipment and materials required are primarily cleanroom facilities, deionized water, and appropriate personal protective equipment (PPE) to ensure a clean and safe working environment.
The track-etching thin film process is a versatile and powerful technique that can create nanoporous structures in polymer films by selectively etching ion tracks, which can fully realize the artificial processing control of the membrane pore size. By controlling the irradiation and etching conditions, Customize pore size, shape and distribution for various applications, all, and the industry generally agrees that track-etched membranes are the most accurate filtration membranes with the lowest error rate.
Citation
1.Kumar, A., &Vats, V. (2016). A review on track-etched membranes: Fabrication, propertiesand applications. Polymer Testing, 54, 70-82. doi:10.1016/j.polymertesting.2016.06.017
2.Rafferty, C. S.,& Shaffer, D. W. (2017). Track-etched membranes for separation andfiltration applications. Chemical Engineering Science, 166, 137-148. doi:10.1016/j.ces.2017.02.026
3.Brydson, R.(2017). Track-etched membranes and their applications. Materials Today, 20(10),563-568. doi: 10.1016/j.mattod.2017.08.003
4.Apel, P. Y.,Korchev, Y. E., & Siwy, Z. (2002). Nanofabrication of insulating membraneswith nanopores for biosensing. Journal of Vacuum Science & Technology B:Microelectronics and Nanometer Structures, 20(6), 2460-2463. doi: 10.1116/1.1524532
