FTIR studies on plasticization of silicate glass with ionic liquids (conversion to silicate polymers)

Inorganic polymers were synthesized via the conversion of silica to silicate glass, followed by plasticization with ionic liquid (IL). The aim of this work is to elucidate the plasticization mechanism by using attenuated total reflectance - Fourier transform infrared spectroscopy. Specifically, this work focuses on inorganic polymers derived from silicate glasses, which contain either K+ ions or K+/Ca2+ ions, and IL; e.g., 1-ethyl-3-methylimidazolium (EMIM) trifluoromethanesulfonate (TF). Herein, we build upon our previous hypothesis and further corroborate that the plasticization mechanism follows a cation exchange reaction (e.g., between K+ ions from silicate glass and EMIM+ ions from IL). A systematic variation in our synthesis conditions reveal that the 640 cm- 1 vibrational band can be assigned to Si-O-???+EMIM cation-motion vibration. In addition, the vibrational features at 908 cm- 1 and 877 cm- 1 are assigned to cation-motion vibrations of Si-O- ??? 2+Ca/2 and Si-O- ??? +K bonds, respectively.