Structural Design of Mesoporous Silica by Micelle-Packing Control Using Blends of Amphiphilic Block Copolymers

TLDR: In this article, the formation of mesoporous silica materials using blends of diblock (CnH2n+1(OCH2CH2)xOH, CnEOx, n = 12 − 18 and x = 2−100) and Pluronic triblock (EOxPO70EOx, x = 5 − 100) amphiphilic block copolymers as structure-directing agents and sodium silicate as the silica source.

Abstract: The formation of mesoporous silica materials has been studied using blends of diblock (CnH2n+1(OCH2CH2)xOH, CnEOx, n = 12 − 18 and x = 2−100) and Pluronic triblock (EOxPO70EOx, x = 5−100) amphiphilic block copolymers as the structure-directing agents and sodium silicate as the silica source. The mesostructure of the silica materials thus obtained, as determined by X-ray diffraction and transmission electron microscopy, changes as the volume of the hydrophilic EO group of the surfactant increases, from lamellar to two-dimensional hexagonal (p6mm), three-dimensional hexagonal, a cubic phase, and another cubic phase with Im3m symmetry. Particle morphologies of the mesoporous silica materials are correspondingly changed from sheetlike to irregular, facetted cubic shapes depending on the periodic mesoscale symmetry of the structure. It is reasonable that the structural transformations are due to the changes in hydrophobic surface curvatures, which can be controlled readily and precisely by using polymer blend...