The potential applications of cationic poly(ionic liquids) range from medicine to energy storage, and the development of efficient synthetic strategies to target innovative cationic building blocks is an important goal. A post-polymerization click reaction is reported that provides facile access to trisaminocyclopropenium (TAC) ion-functionalized macromolecules of various architectures, which are the first class of polyelectrolytes that bear a formal charge on carbon. Quantitative conversions of polymers comprising pendant or main-chain secondary amines were observed for an array of TAC derivatives in three hours using near equimolar quantities of cyclopropenium chlorides. The resulting TAC polymers are biocompatible and efficient transfection agents. This robust, efficient, and orthogonal click reaction of an ionic liquid, which we term ClickabIL, allows straightforward screening of polymeric TAC derivatives. This platform provides a modular route to synthesize and study various properties of novel TAC-based polymers.

The self-assembly of diblock copolymers (BCPs) comprising flexible polymer chains, driven by a balance of enthalpic and entropic forces, is well understood. If one of the blocks is a polyelectrolyte, forming a chargeneutral BCP (CN-BCP), Coulombic interactions can play a significant role in the self-assembly. Here, electron microscopy and small-angle X-ray scattering, in combination with free-energy arguments and a scaling model inspired by surfactant self-assembly, are used to investigate the microphase segregation of CN-BCPs having pendent trisaminocyclopropenium (TAC) ions. We find that the TAC polymer electrolytes have an unexpectedly low dielectric constant (∼2.5) and that CN-BCPs containing a TAC polymer electrolyte block exhibit highly asymmetric morphology diagrams. These CN-BCP morphology diagrams have an unexpectedly large range of CN-BCP compositions where cylinders form, with the TAC block forming the continuous matrix, and in contrast to conventional BCPs, these cylindrical phases form even when the charged block is a minority constituent. These unusual morphologies observed in CN-BCPs with strong electrostatic interactions may thus provide a foundation for the exploration of new modes of ion transport in BCP selfassemblies.

A technique to measure the cation-transference number of salts in fully hydrated ion-selective membranes has been developed and demonstrated on Nafion 117 for LiCl and Li 2 SO 4 . Dilute solution theory is used to identify experimental conditions that reduce the propagation of uncertainties in membrane properties to transference number estimates. This technique has advantages over commonly used methods, including the elimination of the need for the analysis of electrode potentials in approaches that exploit electroanalytical methods or the need for additional information required to reconcile NMR-based methods with the bulk transport property. It additionally allows for numerous measurements per day and offers the possibility to relate trace measurements of either cations or anions to values of transference number. For LiCl both modes of the technique were employed; the anion-tracer method is more precise and gives t + = 0.936 ± 0.010. The experimental procedure was repeated using the cation-tracer method for Li 2 SO 4 , and t + = 0.95 ± 0.06 was estimated. The 21 st century presents a key challenge in energy storage due to the intermittency of wind and solar energy sources. Lithium ion batteries, fuel cells, and redox flow batteries are promising technologies for energy storage since they have high energy densities, are environmentally friendly, and have an array of other desirable properties. [1][2][3][4][5][6] Solid electrolytes are ubiquitous for these energy storage systems since they serve the important function of mechanical separation between electrodes. In addition, solid electrolytes circumvent several problems associated with liquid electrolytes such as the leakage of electrolyte solution and the reaction of volatile organic solvents.7 Of the solid electrolytes, polymer electrolytes have garnered the most interest in recent years. [8][9][10][11] These membranes facilitate ionic transport between electrodes, inhibit electron flow between electrodes, prevent direct contact between electrodes, and minimize mixing of the anolyte and catholyte.In recent decades, researchers have sought to understand the relationship between the molecular structure of polymer electrolytes and their performance. These structure-property relationships have been developed for two major types of polymer electrolytes: (I) mixtures of salts in high molecular weight polymers and (II) polymerized ionic liquids (single ion conductors). Polyethylene oxide (PEO), polypropylene oxide (PPO), and 4 poly[bis(methoxy-ethoxyethoxy) phosphazene] (MEEP) are all promising Type I polymer electrolytes.12-16 The electron-donating groups incorporated into the polymer architecture are responsible for solvating the lithium ion while the fast segmental dynamics promote high ionic conductivities through fluctuation-driven diffusion. [17][18][19] However, Type I polymer electrolytes typically suffer from poor mechanical properties, which is an unfortunate compromise for the fast segmental dynamics. Furthermore, Type I polymer electrolytes have relative...

The use of nanoparticles (NPs) to compatibilize immiscible polymer blends remains an ongoing challenge requiring a high level of control over the NP dispersion and localization. Here, we show that silica NPs "sparsely" grafted with long polystyrene (PS) chains are surfactant-like because they permit core−core, core−matrix, and corona−matrix interactions. When placed at an immiscible polymethyl methacrylate (PMMA)−PS interface, the silica core strongly interacts with one component (PMMA), while the corona mixes with the other (PS). These carefully designed NPs are demonstrated to be efficient stabilizers, even outperforming block copolymers. While such surfactant-like behavior is evident, and understood on the basis of existing ideas, a new concept that we leverage is how the shape of the interfacial free energy profile is affected by the surface grafting density. For an optimally chosen grafting density and graft chain length, we find a nearly symmetric free energy profile as a function of the NP contact angle at the interface, ensuring that the NPs are strongly localized in a region where they are the most efficient in terms of stabilization.

Polymer electrolytes, which are commonly used as separator materials in electrochemical devices, have ionic conductivity that is thought to be controlled by segmental mobility. Thus, any improvements made toward increasing ionic mobility come at the expense of mechanical integrity. However, selectively solvating the ionic domain, the region responsible for ion conduction, with water or polar organic solvents presents a potential opportunity to circumvent this physical constraint. Here, we explore the role of hydration on the transport properties of membranes formed from randomly sulfonated polystyrene (PS-r-sPS). We find that the water volume fraction underpins an intrinsic trade-off between separator permselectivity (Ψm) and ion conductivity (κ)thus, improvements in ion diffusion because of increased water content come at the expense of charge density in the membrane which yields a reduced Ψm. We provide a summary of the Ψm–κ trade-off for a suite of commercially available separators to elucidate structure–property relationships and present methodologies for improving both Ψm and κ.