Nanologica AB , Drottning Kristinas Väg 61, SE-114 28 Stockholm, Sweden.
Langmuir. 2013 Sep 24;29(38):12003-12. doi: 10.1021/la401532j. Epub 2013 Sep 11.
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°. 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.
已经开发出一种基于使用叶酸超分子模板形成有序介孔硅的方法。基于原位小角 X 射线散射（SAXS）、电子显微镜、红外光谱和原位电导率测量的证据用于研究有机-无机相互作用和合成机制。叶酸分子在溶液中的行为与通常用于制备有序介孔硅相的表面活性剂明显不同，特别是不存在临界胶束浓度。原位 SAXS 研究显示 X 射线散射强度的波动与围绕叶酸模板的硅前驱体的缩合以及在初始阶段的硅介孔结构的生长一致。高角度 X 射线衍射表明，即使在合成几分钟后，叶酸模板在孔内仍然有序。在介孔硅孔内叶酸自组装成手性四聚体的直接结构数据为叶酸四聚体的对位堆叠提供了证据，导致四聚体的旋转表面，旋转角度为 30°。此外，孔内自组装的叶酸能够通过四聚体的腔空间吸附大量的 CO2 气体。该研究证明了使用天然存在的模板来生产相关和功能性介孔材料的有效性。
