Evolution of packing parameters in the structural changes of silica mesoporous crystals: cage-type, 2D cylindrical, bicontinuous diamond and gyroid, and lamellar

J Am Chem Soc. 2011 Aug 3;133(30):11524-33. doi: 10.1021/ja200683t. Epub 2011 Jul 8.

Abstract

Cage-type, two-dimensional (2D) cylindrical hexagonal (C), bicontinuous diamond (D), bicontinuous gyroid (G), and one-dimensional (1D) lamellar (L) structures of silica mesoporous crystals (SMCs) were obtained by using the anionic surfactant N-stearoyl-l-glutamic acid (C(18)GluA) as a template in the presence of the nonionic surfactant C(16)(EO)(10) (Brij-56). The mesostructures were controlled by the organic/inorganic interface curvature change induced by Brij-56. A synthesis-field diagram showed that the mesostructure changed in the sequence cage-type → C → intergrowth of C and D → intergrowth of C and G → D → G → L with increase of the amount of Brij-56. Mixed micelles were formed by the anionic and nonionic surfactants, the packing parameter g of which increased with increasing the addition amount of nonionic surfactant and the reaction temperature. The local g parameter was obtained from electron crystallography reconstruction results by calculating mean curvatures and Gaussian curvatures from the equi-electrostatic potential surface. The intergrowth of C and D and two kinds of intergrowth of C and G are also discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Crystallography, X-Ray
  • Models, Molecular
  • Particle Size
  • Porosity
  • Silicon Dioxide / chemical synthesis
  • Silicon Dioxide / chemistry*
  • Surface Properties
  • Surface-Active Agents / chemistry

Substances

  • Surface-Active Agents
  • Silicon Dioxide