IBN Engineers World's First Tri-Continuous Mesoporous Silica
News Apr 09, 2009
Singapore's Institute of Bioengineering and Nanotechnology (IBN) has developed the first tri-continuous mesoporous material using a surfactant template this completely new porous structure had previously only been predicted mathematically.
Recently published in Nature Chemistry, this novel material, which is named IBN-9 after the research institute, is the first hexagonal nanoscale construct with 3 unconnected interwoven channels. It is by far the most complex mesoporous nanostructure to have been synthesized in real-life and represents a new class of mesoporous materials.
Mesoporous silica materials have huge surface areas, making them ideal for use as catalysts to facilitate chemical reactions. Their uniform nanometer-sized pores allow them to separate molecules by size difference. Their pores may also be used to trap drug molecules for controlled drug release. The ability to tailor the pore structure of mesoporous material is therefore of fundamental importance for various chemical and biological applications.
"IBN-9 demonstrates that it is possible to create three interwoven but independent pore channel systems along with a unique nano-fiber morphology. Such a mesostructure makes distinct diffusion rates in different directions possible. This property would be very attractive for gas separation and drug delivery systems," said IBN Executive Director Professor Jackie Y. Ying, who led this research.
Prior to IBN's work, there has already been tremendous interest towards tailoring mesoporous materials with pore structures and pore sizes. The most complex of these were the bi-continuous structures, which contain two unconnected interwoven channels. These materials are synthesized via self-assembly of silica around surfactant templates.
IBN researchers successfully synthesized the first tri-continuous mesoporous structure by using a specially designed surfactant template, N, N-dimethyl-L-phenylalanine. This surfactant has a unique tunable head-group as well as a long hydrocarbon tail that has variable levels of hydrophobic (water-repellent) qualities.
By systematically changing the synthesis conditions using this surfactant, IBN researchers are able to achieve structures with increasing mean curvatures from the bi-continuous cubic IBN-6 to the tri-continuous 3D hexagonal IBN-9, and finally to the 2D hexagonal IBN-10. The structural complexity of IBN-9 and its sister materials opens the possibility of creating even more complex multi-continuous mesostructures.