Joint-Linker Type Ionic Gels Using Polymerizable Ionic Liquid as a Crosslinker via Thiol-Ene Click Reactions.

Kumkum Ahmed,Aoi Inagaki,Naofumi Naga

doi:10.3390/polym12122844

Kumkum Ahmed, Aoi Inagaki + Show 1 more

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https://doi.org/10.3390/polym12122844

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Journal: Polymers	Publication Date: Nov 29, 2020
Citations: 2	License type: CC BY 4.0

Affiliation: Shibaura Institute of Technology

Abstract

In this work, we report the synthesis of ion-conductive gels, or ionic gels, via thiol-ene click reactions. The novel gel systems consist of the multifunctional thiol monomers tris[(3-mercaptopropionyloxy)-ethyl]-isocyanurate (TEMPIC), pentaerythritol tetrakis(3-mercaptopropionate) (PEMP), and dipentaerythritol hexakis(3-mercaptopionate) (DPMP) as joint molecules and bifunctional allyl ionic liquid (IL) as a crosslinker. The thiol-ene reaction was carried out in lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) in a propylene carbonate (PC) (1 M) solvent system via a photopolymerization process. The chemical structure and mechanical, thermal, and conductive properties of the gels were investigated using Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), compression tests, and impedance spectroscopy, respectively. The mechanical and conductive properties of the ionic gels were found to be largely dependent on the monomer content and functionalities of the joint molecules. TGA revealed good thermal stability of the gels up to 100 °C. An ionic conductivity of 4.89 mS cm−1 was realized at room temperature (298 K) for low-functional thiol monomers, and a further increase in ionic conductivity was observed with an increase in Li+ ion content and temperature.

Highlights

Polymeric gels have created well-adjusted fusion in the fields of physics, chemistry, and material science, resulting in significant advancements in the properties of gels and functional materials.A wide variety of polymeric gels, such as physical gels, hydrogels, organogels, ionogel/ionic gels, and aerogels have been developed for diverse applications in numerous fields [1,2,3,4,5].Among them, gels containing ionic groups in their polymeric network offer numerous prospects in the electrochemistry and energy sectors
Bands in the region of 2924–2987 cm−1 and 3110–3150 cm−1 represent the stretching of −CH groups with a peak at 1564 cm−1 for the C=C double bonds of the imidazole ring of the ionic liquid (IL), which is in good agreement with previously reported ILs containing TFSI anions and imidazolium cations [21,22,23,24]
We successfully fabricated a novel type of multifunctional ionic gel with variable structures and properties via thiol-ene click chemistry

Summary

Introduction

Polymeric gels have created well-adjusted fusion in the fields of physics, chemistry, and material science, resulting in significant advancements in the properties of gels and functional materials.A wide variety of polymeric gels, such as physical gels, hydrogels (double network hydrogels, shape memory hydrogels, interpenetrating polymer networking [IPN] hydrogels, etc.), organogels, ionogel/ionic gels, and aerogels have been developed for diverse applications in numerous fields [1,2,3,4,5].Among them, gels containing ionic groups in their polymeric network offer numerous prospects in the electrochemistry and energy sectors. ILs are salts with poorly coordinated ions, which results in these solvents being liquid below 100 ◦ C or even at room temperature. They offer several attractive properties, such as non-volatility, non-flammability, a wide electrochemical window, high thermal stability, and high ionic conductivity. These characteristics have made them potential candidates for use in gel polymer electrolytes and batteries [6,7,8].

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