Free-standing and bridged amine-functionalized periodic mesoporous organosilica films

Abstract

In this work, we report the first successful synthesis of free-standing and bridged amine-functionalized PMO films grown at the air–water interface using 1,2-bis(triethoxysilyl)ethane (BTEE) and bis[(3-trimethoxysilyl)propyl]amine (BTMSPA) as silica sources and cationic alkyltrimethylammonium surfactant as the structure-directing agent. The films with thickness from 50 to 380 nm had a highly ordered periodic mesostructure with a two-dimensional (2D) hexagonal closed-packed arrangement of channels running parallel to the surface. The typical pore diameter and surface area of the film after solvent-extraction were 28.9 Å and 630 m² g⁻¹, respectively, when the film was synthesized at 95 °C for 8 h with the reaction composition of 1.0 BTEE : 0.05 BTMSPA : 0.57 C₁₆TABr : 2.28 NaOH : 336 H₂O. ²⁹Si and ¹³C cross polarization (CP) MAS NMR spectra identified that the organic-inorganic moieties (Si–CH₂–CH₂–Si and Si–(CH₂)₃NH(CH₂)₃–Si) are the basic structural unit in the film.