Investigation of the effect of silica sources on ionogels prepared from imidazolium based ionic liquid via sol-gel method

Abstract

Ionic liquids have interesting properties such as high ionic conductivity, high thermal and electrochemical stability, low vapor pressure, non-volatility, wide liquid range and the ability to dissolve various organic/inorganic materials. Even though these properties provide advantageous for the use of ionicliquids in various technological devices;problems such as leakage and portability limits the the use of ionicliquids. In recent years, ionogels have gained significant value by overcoming the liquid form problems and by preserving the basic properties of ionic liquids. In this study, imidazolium based ionic liquidwas changed to ionogel by using a silica source such as tetraethylorthosilicate (TEOS), tetramethylortosilicate (TMOS) and methyltrimethoxysilane (MTMS), and formic acid was used as both solvent and catalyst.The effects of different silica sources, molar ratios of components, gelling and aging time on ionogel formation were investigated by experimental studies.Synthesized ionogels were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy andUltraviolet-Visible (UV-Vis) Spectroscopy analyzes.The stable ionogels were obtained with 1:8 silica: formic acid molar ratio, 96 hours of gelation time and 8 days of aging time.It has been determined that the synthesized ionogels have smooth and transparent structure.