Polymerized and Colloidal Ionic Liquids─Syntheses and Applications

Abstract

The breadth and importance of polymerized ionic liquids (PILs) are steadily expanding, and this review updates advances and trends in syntheses, properties, and applications over the past five to six years. We begin with an historical overview of the genesis and growth of the PIL field as a subset of materials science. The genesis of ionic liquids (ILs) over nano to meso lengthscales exhibiting 0D, 1D, 2D, and 3D topologies defines colloidal ionic liquids, CILs, which compose a subclass of PILs and provide a synthetic bridge between IL monomers (ILMs) and micro to macroscale PIL materials. The second focus of this review addresses design and syntheses of ILMs and their polymerization reactions to yield PILs and PIL-based materials. A burgeoning diversity of ILMs reflects increasing use of nonimidazolium nuclei and an expanding use of step-growth chemistries in synthesizing PIL materials. Radical chain polymerization remains a primary method of making PILs and reflects an increasing use of controlled polymerization methods.Step-growth chemistries used in creating some CILs utilize extensive cross-linking. This cross-linking is enabled by incorporating reactive functionalities in CILs and PILs, and some of these CILs and PILs may be viewed as exotic cross-linking agents. The third part of this update focuses upon some advances in key properties, including molecular weight, thermal properties, rheology, ion transport, self-healing, and stimuli-responsiveness. Glass transitions, critical solution temperatures, and liquidity are key thermal properties that tie to PIL rheology and viscoelasticity. These properties in turn modulate mechanical properties and ion transport, which are foundational in increasing applications of PILs. Cross-linking in gelation and ionogels and reversible step-growth chemistries are essential for self-healing PILs. Stimuli-responsiveness distinguishes PILs from many other classes of polymers, and it emphasizes the importance of segmentally controlling and tuning solvation in CILs and PILs. The fourth part of this review addresses development of applications, and the diverse scope of such applications supports the increasing importance of PILs in materials science. Adhesion applications are supported by ionogel properties, especially crosslinking and solvation tunable interactions with adjacent phases. Antimicrobial and antifouling applications are consequences of the cationic nature of PILs. Similarly, emulsion and dispersion applications rely on tunable solvation of functional groups and on how such groups interact with continuous phases and substrates. Catalysis is another significant application, and this is an historical tie between ILs and PILs. This component also provides a connection to diverse and porous carbon phases templated by PILs that are catalysts or serve as supports for catalysts. Devices, including sensors and actuators, also rely on solvation tuning and stimuliresponsiveness that include photo and electrochemical stimuli. We conclude our view of applications with 3D printi...

Leaflet-heterostructures by MWCNT self-assembly following electrospinning

“…First, a stabilizer that provides thermodynamically stable dispersions in water of MWCNTs is prepared. In this study, we used a polymerized ionic liquid, 38 , 39 , 40 a nanolatex (NL) stabilizer based on an ionic liquid monomer, ILBr, 41 , 42 , 43 , 44 co-polymerized with methyl methacrylate, MMA. This NL stabilizer, lightly cross-linked due to alkyl scrambling during ILBr synthesis to produce N,N-bis[1-(2-acryloyloxyundecyl)]imidazolium bromide as a minor side product, 45 , 46 was synthesized by microemulsion polymerization 41 , 42 , 43 , 44 ( Figure 1 A) and has been used to produce aqueous MWCNT dispersions at up to 17% by weight MWCNT.…”

Eco-Fabrication of Gradient Porous Membranes with Uniform Carbene-Stabilized Silver Species for Pollutant Integrated Treatment

“…Notably, adsorption techniques, membrane separation, and catalytic degradation have been flourishing research directions due to their superiorities of low cost, high efficiency, and applicability under mild conditions. − Different adsorbents prepared from natural sources and functionalized ones have proven to be effective, driving industrial upgrades and enhancing environmental sustainability. , However, challenges persist as large quantities would be required to achieve excellent results due to their macroaggregated nature coupled with expensive production and regeneration . Among the numerous membrane materials, polyelectrolyte porous membranes (PPMs) have received considerable interest. − Their ionic feature endows them with unique functions and tailorable properties, making them suitable for a wide range of potential applications, including sensors, separation, filtration, actuation, and catalysis. , Notably, in catalysis, the porous structures can provide support for immobilizing catalysts and permit flow of reactions within the membrane. , Poly(ionic liquid) (PIL), a subclass of polyelectrolytes incorporating ionic liquids into the polymeric backbone, combines the advantageous properties of ionic liquids (e.g., high thermal and electrochemical stability, high ionic conductivity, and low flammability) with the desirable attributes of macromolecular polymers (e.g., designability, processability, and flexibility). , As for the further degradation of pollutants, various methods, including chemical, biological, photocatalytic, and metal nanoparticle-based (NP-based) catalytic reductions, have been extensively explored in the literature. − NP-based catalytic reduction, in particular, holds promise due to its large surface area, good catalytic activity, high efficiency, and excellent electron transfer capability. − However, challenges such as agglomeration-induced decrease in catalytic activity, and difficulties in recycling and reuse of the nanoparticles persist . Both problems may be overcome by immobilization of NPs onto some solid support, but new challenges arise, such as achieving uniform distribution of the NPs throughout the entire matrix and preventing leaching. − …”

Water Molecule as a Dynamic Cross-Linker for Creating Multifunctional Poly(ionic liquid) Porous Membranes

“…As a subclass of polyelectrolytes synthesized via the polymerization of monomeric ILs, PILs have recently emerged as a new research focus in the polymer materials and membrane science communities. − The physicochemical properties (e.g., glass transition temperature, hydrophilic and hydrophobic properties, polarity, etc.) of PILs can be altered much more broadly than those of traditional polyelectrolytes by rational design of both cationic and/or anionic chemical structures. , These unique characteristics offer an alternative and promising material platform to create functional SPPMs.…”