Photopolymerization Behavior of Coordinated Ionic Liquids Formed from Organic Monomers with Alkali and Alkaline Earth Metal Bistriflimide Salts

Abstract

Coordinated ionic liquid (IL) monomers provide many of the benefits of conventional ILs in radical polymerization with the advantage of relatively simple synthesis and recovery of the polymer product. Previous studies have reported high solubilities of lithium bistriflimide in polar organic monomers such as methyl methacrylate (MMA), 1‐vinylimidazole (VIm) and others. Here, coordinated IL monomers are formed comprising a variety of alkali and alkaline earth Mn+(Tf2N−)n salts with MMA and VIm, and polymerization behavior is investigated using real‐time attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT‐IR). The size and valency of the coordinated Mn+ cations are observed to strongly influence monomer reactivity, as evidenced by significant changes in FT‐IR spectra. This work further demonstrates that the bulky, delocalized [Tf2N]− anion allows for facile introduction of a wide range of Mn+ cations into organic polymers without phase separation, which may open opportunities for new composite materials.

How Do Ionic Liquids “Fold” Ionenes? Computational and Experimental Analysis of Imidazolium Polymers Based on Ether and Alkyl Chain Variations Dissolved in an Ionic Liquid

“…The ethercontaining segments in a block sequence are moderately coiled, while this coiling is more pronounced in an alternating polymer. Similar behavior is observed in the chain end-to-end distance shown in Figure 3b, which decreases ∼33% going from PD 10 to PE 10 .…”

“…By grafting the polymers with ethylene glycol, the resulting CO 2 selectivity was found to be significantly enhanced. , Unlike traditional vinyl PILs, ionenes are typically polymerized via step-growth methods which provide access to a much larger array of functional groups between ionic moieties, and placing the charged residue directly with the main polymer backbone often leads to increased separation performance. − The properties of ionenes can vary widely due to the presence of different functionalities, such as the cation species, anion species, copolymer structure, or stereochemical arrangements . In particular, we have recently combined molecular-level simulations and experiments to investigate the design space relevant to high-performance ionenes for gas separation applications. − O’Harra and Bara broadly reviewed high performance ionenes and more recently presented a focused perspective on imidazolium ionene derivatives, such as those containing simple alkyl or aryl linkages and those with more sophisticated functional (i.e., imide, amide) and unique structural (i.e., Tröger’s base) features, commenting on opportunities for designing tunable ionenes for advanced applications including gas separation membranes. Furthermore, different chemical sequences within imidazolium polymers provide direct control of the polymer properties for the targeted application, and different functionalities may lead to strong molecular migrations and local clustering in imidazolium-based mixtures .…”

Systematic Investigation of the Photopolymerization of Imidazolium‐Based Ionic Liquid Styrene and Vinyl Monomers

“…Work involving DSC has also demonstrated structure dependent differences in conversion of acrylate‐functionalized imidazolium‐based ILs . Recently, we have examined the radical photopolymerization kinetics of ILs formed from coordinated ions that arise when lithium bistriflimide (LiTf 2 N) and similar salts are dissolved in polar organic monomers . In comparison to neat monomer samples, these “coordinated” ILs displayed increased rates of polymerization and final monomer conversion.…”

Vinylimidazole–based Polymer Electrolytes with Superior Conductivity and Promising Electrochemical Performance for Calcium Batteries

“…Table 1 provides comparative values between the ether and the imidazole moieties in terms of dielectric constant, donor number, and dipole moment. The imidazole group is a planar 5-membered ring consisting of two nitrogen atoms, and shows the capability to coordinate well to cations, [21][22][23][24][25][26] owing to the high donor capability among its class of N-containing 5 and 6 member rings (e.g., similar structures such as 3-methylpyridine and 4-methylpyridine possess donor numbers of 36 and 39, respectively). The imidazole moiety also presents a more delocalized electron donating group (i.e., polarizable) which can offset the strong complexation properties of Ca 2+ .…”

“…27 The free imidazole peak is also found to shift (Figure 1, PVIm-0.1 vs. PVIm-0.5 M and PVIm-1.0), further suggesting a higher degree of N-Ca 2+ coordination upon photopolymerization compared to their liquid counterparts (not for PVIm-1.0). Two plausible explanations can be provided for the increase in imidazole-Ca 2+ coordination going from liquid to polymer -1) the ability of triflimide salt cations to form physical crosslinks 25 more easily between imidazole pendant groups now "tethered" along the polymer chains as opposed to free form imidazole groups in the liquid state, as well as 2) the associated densification upon polymerization, which also brings pendant groups closer together. As more salt is added to the polymer, the percentage of unpaired TFSIanions remain at ~50%, but imidazole-Ca 2+ coordination increases, implying that excess Ca 2+ must coordinate with the imidazole.…”