Preparation and characterization of periodic mesoporous organosilica terminally functionalized with fluorocarbon groups by a direct synthesis

Abstract

Fluorocarbon groups were used to modify the pore channels of ethane-bridged periodic mesoporous organosilica by the co-condensation of 1,2-Bis(triethoxysilyl)ethane (BTESE) and trifluoropropyltrimethoxysilane (TFPTMS) in the presence of Poly(ethylene glycol)-B-Poly(propylene glycol)-B-Poly(ethylene glycol) (P123) surfactants under acidic conditions. The functionalized materials were investigated in detail by means of XRD, TEM, FT-IR, solid-state NMR, and N2 adsorption. The effect of fluorocarbon groups concentration on the mesoscopic order and pore structure of the functionalized materials was also studied. The results show that bridging groups in the framework do not cleave and fluorocarbon groups are attached covalently to the pore wall of periodic mesoporous organosilica after functionalization. The samples functionalized with 20% TFPTMS remain desired mesoporous architecture, with a narrow pore size distribution centered at 4.1 nm, a large surface of 834 m2/g and a pore volume of 0.91 cm3g−1, without pronounced change compared to the pure periodic mesoporous organosilica. Unfortunately the functionalized materials become structurally disordered with increasing amount of fluorocarbon groups.