Image: Langmuir-Blodgett technology is used to prepare polymer nanosheets-the precursor of smart porous membranes. See more
A research team has developed an ion-selective smart porous membrane that can respond to external stimuli, which may pave the way for new applications in molecular separation and sensing applications.
Porous membranes have attracted the attention of scientists due to their potential uses in sensors, energy harvesting, and ion/molecule separation.
Nanostructure characteristics, such as pore size, thickness, and membrane density, affect molecular selectivity and molecular permeability. Surface properties also have a significant impact on molecular selectivity.
Therefore, it is very important to be able to control the 3D nanostructure and surface properties of the ultra-thin porous membrane.
Previous research revealed smart porous membranes covered with molecules that can respond to external stimuli such as light, temperature, and pH. However, applying them to porous films with extremely thin film thicknesses below 10 nm has proven to be extremely challenging for scientists.
Yuya Ishizaki of the Graduate School of Engineering at Tohoku University said: "In our research, we successfully developed a responsive porous SiO2 film with an extremely thin film thickness of 8 nm and a surface uniformly covered in a pH-responsive silane coupling agent. and Co-author of the study. "The responsive porous membrane can adjust the surface charge according to the pH change in the solution to achieve selective ion penetration. "
In order to prepare porous films with nanometer-scale precision and a controllable structure, the research team focused on polymer films containing silsesquioxane with a unique cage structure.
The polymer film is manufactured using Langmuir-Blodgett technology and was chosen because it provides molecular-level controllability of film thickness. Langmuir-Blodgett polymer nanosheets can also produce porous SiO2 films with controlled nanostructures through simple ultraviolet irradiation under environmental conditions.
"We plan to develop efficient separation membranes and sensing materials in the future to take advantage of extremely thin film thicknesses and controllable surface characteristics," Ishizaki added.
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Masaya Mishoku masaya@tohoku.ac.jp
Copyright © 2021 American Association for the Advancement of Science (AAAS)
Copyright © 2021 American Association for the Advancement of Science (AAAS)