Molecular design of AEC tri-block anionic surfactant towards rational synthesis of targeted thick-walled mesoporous silica

摘要

Here we report a new synthesis strategy to synthesize thick-walled two dimensional hexagonal mesoporous silicas, using tri-block surfactant fatty alcohol ether carboxylate [AEC: C_nH_(2n+1)O(CH2CH2O)_mCH2COONa] with two different hydrophilic head groups of (EO)_x-block and anionic carboxylate. The unique formation of double-layer silica wall arose from two types of hydrophilic head groups via the silica source condensation led to an obvious increase in the wall thickness. The successful carbon replication proved the existence of micropores formed by imbedded (EO)_x-block and electrostatic bonding of carboxylate head group and organic group of co-structure directing agent. The template-free mesoporous silica showed a high hydrothermal stability due to the thick wall.