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With the rapid development of energy storage technology, the operation of portable and wearable devices is inseparable from high energy density power supplies. However, the demand for high performance supercapacitors in movable smart electronics is still restrained by their insufficient areal capacitance and limited power/energy densities. In addition, some electroactive materials, including metal oxides, conductive polymers, graphene, porous carbons, etc., are inevitable to use extra adhesives for the preparation of electrode materials. In this work, integrated hierarchical graphitic porous carbon membranes used as the electrodes without adhesives are successfully synthesized, via pyrolyzing poly(ionic liquid)s (PILs)‐metal organic frameworks (MOFs) composite membranes. The asymmetric supercapacitor is assembled by the carbonized PIL‐MOF composite membrane and PILs‐derived porous carbon membrane, and exhibits significant areal capacitance with remarkable power and energy densities. In the two‐electrode system, the areal capacitance can reach 9.5 F cm−2 with an energy density of 1.91 mWh cm−2. In the fabricated all‐solid‐state supercapacitors, the areal capacitance and energy density achieved 3.2 F cm−2 and 0.65 mWh cm−2, respectively, exceeding most reported ones. Therefore, the integrated carbon membrane electrodes with high areal capacitance reveal great potential in miniaturized devices, and further show a wider application scope through regulating PILs. [ABSTRACT FROM AUTHOR]

Topological geometry of poly(ionic liquid)s (PILs), such as brush‐like, knot‐like, hyperbranched and randomly coiled, often exerts a strong influence on their self‐assembly behaviors. As a primary topological form, the cyclic topology‐derived effects have not been investigated on PILs, which concerns synergy of charges and zero chain end. Herein, linear and cyclic poly(ionic liquid) copolymers (co‐PILs) with randomly distributed counter anions of B(Ph)4− and Br− by a template method in combination with a follow‐up partial anion exchange is prepared. The self‐assembly phenomena of linear and cyclic co‐PILs are studied in selective solvents, where the hydrophobic counter anions B(Ph)4− and hydrophilic counter anions Br− aggregated to form cores and corona in the assembled nanospheres, showing the average size of cyclic co‐PILs nanospheres is 46.2% smaller (≈120 nm) than linear co‐PILs nano‐assemblies (≈176 nm). Based on the CGMD simulations, the authors speculate that the spherical aggregates are formed by transitioning from micelles with gradient block‐like structures, which formed by enriched hydrophobic counter anions in the core and enriched hydrophilic counter anions in the corona. These results indicate a novel synergy of topology effects and dynamic anion movements, as revealed by cyclic co‐PIL self‐assembly in this work. [ABSTRACT FROM AUTHOR]

4-Methyl-1-vinyl-1,2,4-triazolium triiodide ionic liquid and its polymer poly(4-methyl-1-vinyl-1,2,4-triazolium) triiodide were prepared for the first time from their iodide precursors via the reaction of iodide (I − ) with elemental iodine (I 2 ). The change from iodide to triiodide (I 3 − ) was found to introduce particular variations in the physical properties of these two compounds, including lower melting point/glass transition temperature and altered solubility. The compounds were characterized by single-crystal X-ray diffraction, elemental analysis, and their electrochemical properties examined in solution and in the solid-state. Compared with their iodide analogues, the triiodide salts exhibited lower electrical impedance and higher current in the cyclic voltammetry. We found that poly(4-methyl-1,2,4-triazolium triiodide) was proven to be a promising solid polymer electrolyte candidate. [ABSTRACT FROM AUTHOR]

Porous polyelectrolyte membranes stable in a highly ionic environment are obtained by covalent crosslinking of an imidazolium-based poly(ionic liquid). The crosslinking reaction involves the UV light-induced thiol-ene (click) chemistry, and the phase separation, occurring during the crosslinking step, generates a fully interconnected porous structure in the membrane. The porosity is on the order of the micrometer scale and the membrane shows a gradient of pore size across the membrane cross-section. The membrane can separate polystyrene latex particles of different size and undergoes actuation in contact with acetone due to the asymmetric porous structure. [ABSTRACT FROM AUTHOR]

In this work we studied covalently crosslinked poly(ionic liquid) nanoparticles synthesized via aqueous dispersion polymerization of 1,2,4-triazolium ionic liquid monomers in the presence of a dication crosslinker. Compared to their non-crosslinked counterparts, the nanoparticles showed improved structural integrity in organic media. Assisted by cryogenic electron microscopy, these nanoparticles were analyzed in detail and found to present vastly diverse shapes and highly ordered inner mesostructures. Upon altering the length of the alkyl substituents on the triazolium cation from dodecyl to tetradecyl and hexadecyl, a shape transformation from elongated “nanoworms” to a mixture of “onion-like” and “wasp-like” nanoparticles was observed. Additionally, the size variation of these colloidal nanoparticles was investigated systematically by polymerizations at different concentrations of monomer, external added salt and crosslinking agent. Finally, the crosslinked poly(ionic liquid) nanoparticles were able to readily disperse multi-walled carbon nanotubes in water and organic media. [ABSTRACT FROM AUTHOR]

Abstract This work demonstrates the use of imidazolium-based poly(ionic liquid)s (PILs) as efficient dispersants of multi-walled carbon nanotubes (MWCNTs). With these polymeric dispersants, highly stable fine dispersions of MWCNTs (inks) can be easily prepared in aqueous media and applied for rather simple but efficient surface modification of screen-printed electrodes (SPEs). Such a modification of SPEs remarkably increases the electroactive surface area and accelerates the electron transfer rate due to synergistic combination of specific features of MWCNTs such as strong adsorptive property and high specific surface with the advantages of PILs like ion conductivity and dispersability. We further show that the PIL/MWCNT-modified SPEs can be beneficially utilized for direct electrochemical analysis of double stranded DNA (dsDNA). Specifically, it is exemplified by the direct electrooxidation of guanine and adenine bases in salmon testes dsDNA chosen as a model system. The linear ranges for the determination of dsDNA correspond to 5–500 μg/mL for the oxidative peak of guanine and 0.5–50 μg/mL for the oxidative peak of adenine. This makes direct electrochemical dsDNA detection with the use of the easy-preparable PIL/MWCNT-modified SPEs strongly competing to currently applied spectral and fluorescent techniques. Furthermore, we show that the developed constructs are capable of sensing a single point mutation in the 12-bases single-stranded DNA fragments. Such detection is of high clinical significance in choosing an adequate anticancer treatment, where the electrochemical identification of the point mutation could offer time and cost benefits. Graphical abstract Image 1 Highlights • Imidazolium-based poly(ionic liquid)s (PILs) facilitate dispersing of MWCNTs in aqueous media. • Dispersions of MWCNTs are long-term stable and easy-to-handle for efficient surface modification. • PIL/MWCNTs modified electrode strongly improves direct electroanalysis of double-stranded DNA. • PIL/MWCNTs modified electrode recognizes single point mutations in DNA fragments. [ABSTRACT FROM AUTHOR]