Abstract:
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A method to form ordered mesoporous silica based on the use of folate supramolecular templates has been developed. Evidence based on in situ small-angle X-ray scattering (SAXS), electron microscopy, infrared spectroscopy, ...[+]
A method to form ordered mesoporous silica based on the use of folate supramolecular templates has been developed. Evidence based on in situ small-angle X-ray scattering (SAXS), electron microscopy, infrared spectroscopy, and in situ conductivity measurements are used to investigate the organic inorganic interactions and synthesis mechanism. The behavior of folate molecules in solution differs distinctively from that of surfactants commonly used for the preparation of ordered mesoporous silica phases, notably with the absence of a critical micellar concentration. In situ SAXS studies reveal fluctuations in X-ray scattering intensities consistent with the condensation of the silica precursor surrounding the folate template and the growth of the silica mesostructure in the initial stages. High-angle X-ray diffraction shows that the folate template is well-ordered within the pores even after a few minutes of synthesis. Direct structural data for the self-assembly of folates into chiral tetramers within the pores of mesoporous silica provide evidence for the in register stacking of folate tetramers, resulting in a chiral surface of rotated tetramers, with a rotation angle of 30 degrees. Additionally, the self-assembled folates within pores were capable of adsorbing a considerable amount of CO2 gas through the cavity space of the tetramers. The study demonstrates the validity of using a naturally occurring template to produce relevant and functional mesoporous materials.
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Thanks:
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This work was supported by the Swedish Research Council (Project 2009-4716 AGB). Niklas Hedin acknowledges funding from the Swedish Energy Agency. Luis Angel Villaescusa is grateful for support from the Jose Castillejo ...[+]
This work was supported by the Swedish Research Council (Project 2009-4716 AGB). Niklas Hedin acknowledges funding from the Swedish Energy Agency. Luis Angel Villaescusa is grateful for support from the Jose Castillejo Program of the Spanish Ministry of Sport and Education (Project JC2009-00141). The authors thank Y. Cerenius and M. Knaapila (MAX-lab Synchrotron Facitlity, Beamline 1711, Lund, Sweden) for assistance with SAXS experiments and beamline time.
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