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Hierarchically-porous polymers with fast absorption

Date:
January 20, 2015
Source:
Korea Advanced Institute of Science and Technology
Summary:
Researchers have developed a method to form micropores of less than 2 nanometers within porous polymers.
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Net-like Structure of Hierarchically-Porous Polymers with Mesopores and Micropores on the walls of Mesopores.
Credit: Image courtesy of Korea Advanced Institute of Science and Technology

Researchers at Korea Advanced Institute of Science and Technology (KAIST) has developed a method to form micropores of less than 2 nanometers within porous polymers.

Professor Myungeun Seo and his research team from the Graduate School of Nanoscience and Technology at KAIST has developed a method to form micropores of less than 2 nanometers within porous polymers where 10 nanometers long mesopores connect like a net. The advantage of the porous polymers is fast absorption of molecules.

Porous polymers with micropores of less than 2 nanometers, like a zeolite, have a large surface area. They are used as a means to store hydrogen-based molecules or as a catalytic support that can be used as a surface to convert a material into a desired form. However, because the size of the pores in its path was too small for the molecules, it took a long time to spread into the pores and reach the surface.

To reach the surface efficiently, a lung cell or the vein of a leaf has a structure wherein the pores are subdivided into different sizes so that the molecule can spread throughout the organ. A technology that can create not only micropores but also bigger pores was necessary in order to create such structure.

The research team solved the issue by implementing a "self-assembly" of block polymers to easily form a net-like nanostructure from mesopores of 10 nanometers.

The team created hierarchically-porous polymers consisting of two different types of pores by using a hypercrosslinking reaction along with the "self-assembly" method. The reaction creates micropores within the chain after the polymer chain is confined by a chemical bond.

This porous polymer has micropores that are smaller than 2 nanometers on the walls of mesopores while 10 nanometers long mesopores forming 3-dimensional net structures. Because of the "self-assembly" method, the size of mesopores can be adjusted within the range of 6 to 15 nanometers.

This is the first case where a porous polymer has both well-defined mesopores and micropores. The research team verified the effect of hierarchically-porous structures on absorption of molecules by confirming that the porous polymer had faster absorption speeds than a polymer consisting only of micropores.

Professor Seo said, "The study has found a simple way to create different sizes of pores within a polymer." He expected that the hierarchically-porous polymers can be used as a catalytic support in which fast diffusion of molecules is essential, or for molecule collection.

The research was sponsored by National Research Foundation of Korea and published online in the Journal of the American Chemical Society.


Story Source:

Materials provided by Korea Advanced Institute of Science and Technology. Note: Content may be edited for style and length.


Journal Reference:

  1. Myungeun Seo, Soobin Kim, Jaehoon Oh, Sun-Jung Kim, Marc A. Hillmyer. Hierarchically Porous Polymers from Hyper-cross-linked Block Polymer Precursors. Journal of the American Chemical Society, 2015; 150107150852009 DOI: 10.1021/ja511581w

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Korea Advanced Institute of Science and Technology. "Hierarchically-porous polymers with fast absorption." ScienceDaily. ScienceDaily, 20 January 2015. <www.sciencedaily.com/releases/2015/01/150120084547.htm>.
Korea Advanced Institute of Science and Technology. (2015, January 20). Hierarchically-porous polymers with fast absorption. ScienceDaily. Retrieved May 23, 2017 from www.sciencedaily.com/releases/2015/01/150120084547.htm
Korea Advanced Institute of Science and Technology. "Hierarchically-porous polymers with fast absorption." ScienceDaily. www.sciencedaily.com/releases/2015/01/150120084547.htm (accessed May 23, 2017).

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