How Does the Amine Ligand Affect Nanoporous Material Affinity for an Explosives Model?

Abstract

Imprinted polymeric materials can recognize template molecules from vapors or solutions. Organically-modified silicates (ormosils) containing functionalized organosilanes, including phenyl trimethoxysilane and either 3-aminopropyl triethoxysilane (1), 3-(N-methylamino)propyl trimethoxysilane (2), or 3-(N,N-dimethyl-3-aminopropyl) trimethoxysilane (3). The ormosils were spin-coated from sol-gel solutions containing template 2, 4-dinitrotoluene (DNT), a model for the explosive 2, 4, 6-trinitrotoluene (TNT). After being heated in an 80?C furnace for an hour to solidify the gels, organic components in the resulting films were quantified with UV spectroscopy, film thicknesses were obtained using profilometry and ellipsometry, and surface hydrophobicity was measured with contract angle geometry. After template extraction with methanol, films were exposed to DNT vapor and then re-extracted. Results of films containing a secondary amine (2) and a tertiary amine (3) will be compared to preliminary data and results using primary amine 1 and the secondary amine 3-(N-methylamino)propyl triethoxysilane with the tertiary amine expected not to show strong affinity for the template DNT. Preliminary results show the rate of extraction was highest when no organic material was present and lowest when primary amine was used.