RESUMEN
A series of clickable α-azide-ω-alkyne ionic liquid (IL) monomers with an ethylene oxide spacer were developed and applied to the synthesis of 1,2,3-triazolium-based poly(ionic liquid)s (TPILs) with high ionic conductivities via one-step thermal azide-alkyne cycloaddition click chemistry. Subsequently, the number of IL moieties in the resultant TPILs was further increased by N-alkylation of the 1,2,3-triazole-based backbones of the TPILs with a quarternizing reagent. This strategy affords the preparation of TPILs having either one or two 1,2,3-triazolium cations with bis(trifluoromethylsulfonyl)imide anions in a monomer unit. Synthesis of the TPILs was confirmed by 1H and 13C NMR spectroscopy and gel permeation chromatography. The effects of the length of the ethylene oxide spacer and the number of IL moieties in the IL monomer unit on the physicochemical properties of the TPILs were characterized by differential scanning calorimetry, thermogravimetric analysis, and impedance spectroscopy. The introduction of a longer ethylene oxide spacer or an increase in the number of IL moieties in the monomer unit resulted in TPILs with lower glass-transition temperatures and higher ionic conductivities. The highest ionic conductivity achieved in this study was 2.0 × 10-5 S cm-1 at 30 °C. These results suggest that the design of the IL monomer provides the resultant polymer with high chain flexibility and a high IL density, and so it is effective for preparing TPILs with high ionic conductivities.
RESUMEN
Clickable α-azide-ω-alkyne ionic liquid monomers were developed and subsequently applied to the one-pot synthesis of ionically conducting poly(ionic liquid)s with 1,2,3-triazolium-based backbones through a click chemistry strategy. This approach does not require the use of solvents, polymerisation mediators, or catalysts. The obtained poly(ionic liquid)s were characterized by NMR, differential scanning calorimetry, thermogravimetric analysis, and impedance spectroscopy analysis. Moreover, these poly(ionic liquid)s were cross-linked via N-alkylation with a dianion quarternizing agent to achieve enhanced ionic conductivity and mechanical strength. The resulting free-standing films showed a Young's modulus up to 4.8 MPa and ionic conductivities up to 4.60 × 10-8 S cm-1 at 30 °C. This facile synthetic strategy has the potential to expand the availability of poly(ionic liquid)s and promote the development of functional materials.