Simple, Robust, and Plasticizer-Free Iodide-Selective Sensor Based on Copolymerized Triazole-Based Ionic Liquid

Novel solid-contact iodide-selective electrodes based on covalently attached 1,2,3 triazole ionic liquid (IL) were prepared and investigated in this study. Triazole-based IL moieties were synthesized using click chemistry and were further copolymerized with lauryl methacrylate via a simple one-step free radical polymerization to produce a "self-plasticized" copolymer. The mechanical properties of the copolymer are suitable for the fabrication of plasticizer-free ion-selective membrane electrodes. We demonstrate that covalently attached IL moieties provide adequate functionality to the ion-selective membrane, thus achieving a very simple, one-component sensing membrane. We also demonstrate that the presence of iodide as the counterion in the triazole moiety has direct influence on the membrane's functionality. Potentiometric experiments revealed that each electrode displays high selectivity toward iodide anions over a number of inorganic anions. Moreover, the inherent presence of the iodide in the membrane reduces the need for conditioning. The nonconditioned electrodes show strikingly similar response characteristics compared to the conditioned ones. The electrodes exhibited a near Nernstian behavior with a slope of -56.1 mV per decade across a large concentration range with lower detection limits found at approximately 6.3 × 10(-8) M or 8 ppb. These all-solid-state sensors were utilized for the selective potentiometric determination of iodide ions in artificial urine samples in the nanomolar concentration range

Water-free proton-conducting polysiloxanes: A study on the effect of heterocycle structure

ABSTRACT: Proton-conducting, thermally and electrochemically stable, heterocycle-grafted polysiloxanes have been synthesized via hydrosilylation of vinyl or allyl functionalized weakly basic heterocyclic motifs with a polymethylhydrosiloxane precursor. The basicity of the amphoteric heterocycles was tuned by introducing electron-withdrawing groups, whose presence also produced a decrease in the polymers ’ glass transition temperature. The proton conductivity depended strongly on the Tg of the polymer matrix and the volume fraction of proton carriers, while the effect of reducing the pKa of the heterocycle was less pronounced. The resulting polymers showed the highest reported proton conductivities of up to 0.1 mS/cm at temperatures below 80 °C and up to 5 mS/cm at 180 °C when doped with trifluoroacetic acid

Communication—sulfonated poly (ether ether ketone) as cation exchange membrane for alkaline redox flow batteries

A sulfonated poly (ether ether ketone) (sPEEK) was tested as the separator in a full alkaline flow battery with 2,6-dihydroxyanthraquinone-ferro/ferricyanide, DHAQ-FeCy, redox couples. Cell performance was compared to that of an identical cell utilizing a perfluorosulfonic acid (PFSA) membrane. Replacement of the PFSA membrane with sPEEK resulted in a 10% power density increase, a 40% decrease in capacity loss per day and an 85-fold decrease in ferricyanide permeation. Though long-term stability of sPEEK in alkaline media requires improvement, these results highlight the potential to produce non-fluorinated membranes with better performance in organic redox flow batteries than the commercially available PFSAs. © The Author(s) 2018

Enhancement of anhydrous proton transport by supramolecular nanochannels in comb polymers

Transporting protons is essential in several biological processes as well as in renewable energy devices, such as fuel cells. Although biological systems exhibit precise supramolecular organization of chemical functionalities on the nanoscale to effect highly efficient proton conduction, to achieve similar organization in artificial systems remains a daunting challenge. Here, we are concerned with transporting protons on a micron scale under anhydrous conditions, that is proton transfer unassisted by any solvent, especially water. We report that proton-conducting systems derived from facially amphiphilic polymers that exhibit organized supramolecular assemblies show a dramatic enhancement in anhydrous conductivity relative to analogous materials that lack the capacity for self-organization. We describe the design, synthesis and characterization of these macromolecules, and suggest that nanoscale organization of proton-conducting functionalities is a key consideration in obtaining efficient anhydrous proton transport