Copper-Free Synthesis of Cationic Glycidyl Triazolyl Polymers

Copper-free synthesis of cationic glycidyl triazolyl polymers (GTPs) is achieved through a thermal azide-alkyne cycloaddition reaction between glycidyl azide polymer and propiolic acid, followed by decarboxylation and quaternization of the triazole unit. For synthesizing nonfunctionalized GTP (GTP-H), a microwave-assisted method enhances the decarboxylation reaction of carboxy-functionalized GTP (GTP-COOH). Three variants of cationic GTPs with different N-substituents [N-ethyl, N-butyl, and N-tri(ethylene glycol) monomethyl ether (EG3)] are synthesized. The molecular weight of GTP-H is determined via size exclusion chromatography. Thermal properties of all GTPs are characterized using differential scanning calorimetry and thermogravimetric analysis. The ionic conductivities of these cationic GTPs are assessed by impedance measurements. The conducting ion concentration and mobility are calculated based on the electrode polarization model. Among three cationic GTPs, the GTP with the N-EG3 substituent exhibits the highest ionic conductivity, reaching 6.8 × 10-6 S cm-1 at 25 °C under dry conditions. When compared to previously reported reference polymers, the reduction of steric crowding around the triazolium unit is considered to be a key factor in enhancing ionic conductivity.

Phosphonium-Based Polyelectrolytes: Preparation, Properties, and Usage in Lithium-Ion Batteries

Phosphorous is an essential element for the life of organisms, and phosphorus-based compounds have many uses in industry, such as flame retardancy reagents, ingredients in fertilizers, pyrotechnics, etc. Ionic liquids are salts with melting points lower than the boiling point of water. The term "polymerized ionic liquids" (PILs) refers to a class of polyelectrolytes that contain an ionic liquid (IL) species in each monomer repeating unit and are connected by a polymeric backbone to form macromolecular structures. PILs provide a new class of polymeric materials by combining some of the distinctive qualities of ILs in the polymer chain. Ionic liquids have been identified as attractive prospects for a variety of applications due to the high stability (thermal, chemical, and electrochemical) and high mobility of their ions, but their practical applicability is constrained because they lack the benefits of both liquids and solids, suffering from both leakage issues and excessive viscosity. PILs are garnering for developing non-volatile and non-flammable solid electrolytes. In this paper, we provide a brief review of phosphonium-based PILs, including their synthesis route, properties, advantages and drawbacks, and the comparison between nitrogen-based and phosphonium-based PILs. As phosphonium PILs can be used as polymer electrolytes in lithium-ion battery (LIB) applications, the conductivity and the thermo-mechanical properties are the most important features for this polymer electrolyte system. The chemical structure of phosphonium-based PILs that was reported in previous literature has been reviewed and summarized in this article. Generally, the phosphonium PILs that have more flexible backbones exhibit better conductivity values compared to the PILs that consist of a rigid backbone. At the end of this section, future directions for research regarding PILs are discussed, including the use of recyclable phosphorus from waste.

Design of Clickable Ionic Liquid Monomers to Enhance Ionic Conductivity for Main-Chain 1,2,3-Triazolium-Based Poly(Ionic Liquid)s

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.

Dual-Cationic Poly(ionic liquid)s Carrying 1,2,4-Triazolium and Imidazolium Moieties: Synthesis and Formation of a Single-Component Porous Membrane

Both imidazolium and 1,2,4-triazolium cations are important functional moieties widely incorporated as building blocks in poly(ionic liquid)s (PILs). In a classical model, a PIL usually contains either imidazolium or 1,2,4-triazolium in its repeating unit. Herein, via exploiting the slight reactivity difference of alkyl bromide with imidazole and 1,2,4-triazole at room temperature, we synthesized dual-cationic PIL homopolymers carrying both imidazolium and 1,2,4-triazolium moieties in the same repeating unit, that is, an asymmetrically dicationic unit. We investigated their fundamental properties, for example, thermal stability and solubility, as well as their unique function in forming supramolecular porous membranes via a water-initiated phase-separation and cross-linking process. With such knowledge, we identified a water-based fabricate strategy toward air-stable porous membranes from single-component PILs. This study will enrich the design tools and chemical structure library of PILs and expand their application spectrum.

Effects of repeat unit charge density on the physical and electrochemical properties of novel heterocationic poly(ionic liquid)s

The higher the charge density of PILs the higher their T_g and the lower their conductivity; the best conductivity (1.8 × 10⁻⁵ S cm⁻¹ at 25 °C): PILs with triazolium cations; the best cathodic stability (−0.4 V vs. Li⁺/Li at 70 °C): PILs with mixed type cations.

Comparison of poly(ethylene glycol)-based networks obtained by cationic ring opening polymerization of neutral and 1,2,3-triazolium diepoxy monomers

The properties of two cross-linked epoxy networks obtained by ring opening polymerization of a synthetic diepoxy 1,2,3-triazolium and a commercial poly(ethylene glycol)diglycidyl ether using benzylamine trifluoroborate as cationic initiator are compared.

Glycidyl Triazolyl Polymers: Poly(ethylene glycol) Derivatives Functionalized by Azide-Alkyne Cycloaddition Reaction

Glycidyl triazolyl polymer (GTP), which is the product of the Huisgen dipolar cycloaddition reaction between glycidyl azide polymer and alkyne derivatives, is featured here. GTP is the multifunctionalized poly(ethylene glycol) (PEG). The drawback of PEG is that linear PEG has the functional group only at both ends. The low loading capability of the functional groups limits the possibilities of PEG applications. GTP facilitates the synthesis of multifunctionalized PEG derivatives. In this article, 74 examples of GTP homopolymers and copolymers are introduced. The synthetic protocols and work-up processes of GTP are summarized. In addition, application studies are reviewed: for example, stimuli-responsive and self-healing materials, materials for electrical memory devices, ion-conductive materials, and biomedical materials. Finally, some issues on GTP synthesis and future directions for GTP-based polymer materials are proposed.

Synthesis and characterization of ureido-derivatized UCST-type poly(ionic liquid) microgels

Ureido-derivatized poly(ionic liquid) microgels, which possess an upper critical solution temperature and can be used in catalytic esterification, are synthesized.

1,2,3-Triazolium-based linear ionic polyurethanes

We report the synthesis and detailed characterization of a series of ionic polyurethanes issued from the polyaddition of a 1,2,3-triazolium-functionalized diol monomer having a bis(trifluoromethylsulfonyl)imide counter-anion with four aliphatic, cycloaliphatic or aromatic commercial diisocyanates.