Emerging Ionic Soft Materials based on Deep Eutectic Solvents

PostprintIn the last five years, the use of deep eutectic solvents (DES) have been opening new perspectives towards the creation of novel ionic soft materials as alternatives to expensive ionic liquids. This Mini-Review highlights the progress and advances in soft ionic materials or gels, mostly composed by a DES immobilized within difference matrices, such as linear polymers, polymer networks, biopolymers, supramolecular compounds or organosilane networks. By taking advantage of the DES characteristics and properties in the solid state, this building system delivers a variety of tailor-made materials showing different functionalities (ionic conductivity, self-healing, stretchability and pH-responsiveness) and offers a way to circumvent drawbacks related to shaping and risk of leakage in many technological applications. In this context, we provide a judicious analysis of these emerging ionic soft materials, their properties and applications open in energy, (bio)electronics, drug delivery, analytical chemistry, and wastewater treatment. Perspectives and opportunities for future research directions on this blossoming field are also discussed.Liliana C. Tomé has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 745734. This work was supported by Marie Sklodowska-Curie Research and Innovation Staff Exchanges (RISE) project under the grant agreement No 823989 “IONBIKE”

Innovative Polymers for Next‐Generation Batteries

Unformatted postprintLithium-ion batteries are part of modern life, being present in daily-used objects such as mobile phones, tablets, computers, watches, sport accessories, electric scooters, and cars. The next-generation batteries require the development of innovative polymers that help to improve their performance in terms of power density, cyclability, raw materials’ availability, low weight, printability, flexibility, sustainability, or security. This article highlights recent developments in the area of redox-active, electronic/ionic conducting polymers. This includes the development of innovative binders for electrodes, polymer electrolytes, and redox polymers. All these new polymer developments are leading to new battery technologies such as metal–polymer batteries, organic batteries, polymer–air, and redox–flow batteries, which are expected to complement the current lithium-ion technologies in the future.Financial support from the Basque Government, Spanish Government and the European Research Council by Starting Grant Innovative Polymers for Energy Storage (iPes) 306250 is acknowledged. L.P. has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska–Curie grant agreement No 797295

Iongel Soft Solid Electrolytes Based on [DEME][TFSI] Ionic Liquid for Low Polarization Lithium-O-2 Batteries

Lithium-air/O-2 batteries are a promising battery technology for automotive applications due to their high energy density. However, many challenges need to be solved, particularly the high reactivity of the electrolyte with oxygen superoxide radicals and its low cyclability. In this work, we present a simple and fast way to prepare polymer-based iongel soft solid electrolytes. Thermally and mechanically stable iongels are prepared by fast UV-photopolymerisation exhibiting a high ionic conductivity (similar to 1.2 x 10(-3) S cm(-1) at 25 degrees C). When used as solid electrolytes in lithium symmetrical cells, they can withstand a critical current density of 0.5 mA cm(-2). Performance in Li-O-2 cells showed capacities as large as 3.3 mAh cm(-2), and cycling capability of 25 cycles, exceeding results on liquid-counterpart cells.European Commission's funded Marie Skłodowska-Curie. Grant Number: 76582

Cation Effect in the Corrosion Inhibition Properties of Coumarate Ionic Liquids and Acrylic UV-Coatings

Chromate free corrosion inhibitors are searched for to mitigate the economic loss caused by mid-steel corrosion. Here, we show metal-free organic inhibitors having free coumarate anions that can be used either as direct corrosion inhibitors or incorporated into a polymer coating obtained by UV-curing. Four different ionic liquid monomers and polymer coatings with hexoxycoumarate anion and different polymerizable counter cations were investigated. Potentiodynamic polarization, electrochemical impedance spectroscopy, and surface analyses have verified their corrosion inhibition performance on a mild steel AS1020 surface. In the case of the coumarate ionic liquid monomers, the most promising inhibitor is the one coupled with the ammonium cation, showing an inhibition efficiency of 99.1% in solution followed by the imidazolium, pyridinium, and anilinium. Next, the ionic liquid monomers were covalently integrated into an acrylic polymer coating by UV-photopolymerization. In this case, the barrier effect of the polymer coating is combined with the corrosion inhibitor effect of the pendant coumarate anion. Here, the best polymer coatings are those containing 20% imidazolium and pyridinium cations, presenting a greater impedance in the EIS (Electrochemical Impedance Spectroscopy) measurements and less evidence of corrosion in the scribe tests. This article shows that the cationic moiety of coumarate based ionic liquids and poly(ionic liquid)s has a significant effect on their excellent corrosion inhibition properties for a mild steel surface exposed to aqueous chloride solutions.The authors would like to thank the European Commission for financial support through funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 823989. E.U. thanks the Spanish MINECO for a FPU fellowship. A.S. and M.F. are grateful for funding from the Australian Research Council through a Discovery Project, DP180101465

Poly(3,4-ethylenedioxythiophene) (PEDOT) Derivatives: Innovative Conductive Polymers for Bioelectronics

Poly(3,4-ethylenedioxythiophene)s are the conducting polymers (CP) with the biggest prospects in the field of bioelectronics due to their combination of characteristics (conductivity, stability, transparency and biocompatibility). The gold standard material is the commercially available poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS). However, in order to well connect the two fields of biology and electronics, PEDOT: PSS presents some limitations associated with its low (bio) functionality. In this review, we provide an insight into the synthesis and applications of innovative poly(ethylenedioxythiophene)-type materials for bioelectronics. First, we present a detailed analysis of the different synthetic routes to (bio) functional dioxythiophene monomer/polymer derivatives. Second, we focus on the preparation of PEDOT dispersions using different biopolymers and biomolecules as dopants and stabilizers. To finish, we review the applications of innovative PEDOT-type materials such as biocompatible conducting polymer layers, conducting hydrogels, biosensors, selective detachment of cells, scaffolds for tissue engineering, electrodes for electrophysiology, implantable electrodes, stimulation of neuronal cells or pan-bio electronics.The work was supported by EU through the projects FP7-PEOPLE-2012-ITN 316832-OLIMPIA and FP7-PEOPLE-2013-ITN 607896-OrgBio. Ana Sanchez-Sanchez is thankful for the Postdoctoral Funding for Doctoral Research Staff Improvement Grant from the Basque Government. David Mecerreyes thanks Becas de Practicas en el Extranjero "Global Training"

Organic batteries based on just redox polymers

[EN]Redox-active polymers have gained interest as environmentally friendly alternative to inorganic materials in applications such as electrodes in lithium-ion batteries. All-polymer batteries were first disregarded with respect to other technologies due to their lower energy densities. However, the inherent benefits of redox polymers such as processability, flexibility, recyclability, high-rate performance and the perspective to prepare batteries from renewable resources has re-ignited interest in recent years. This review article aims to provide a comprehensive overview on the state of the art of batteries in which the active material is a redox polymer; including "static" all-polymer batteries and polymer-air batteries but also "flowing" systems such as polymer based redox-flow batteries (pRFB). First, a succinct overview of the recent developments of redox polymers will be given, summarizing the historic trends and developments. Second, an exhaustive discussion of the various battery prototypes will be provided, considering all steps in the development of organic batteries just based in redox polymers. Finally, future perspectives on all-polymer batteries will be discussed, summarizing the major challenges that are still to be overcome to unlock their commercial implementation.Authors thank POLYSTORAGE ETN project, this project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skodowska-Curie grant agreement No 860403. RM and NP thank the Spanish MCI through the SUSBAT project (Ref. RTI2018-101049-B-I0 0) and Juan de la Cierva fellowship [FJC2018-037781-I] (MCI-AEI/FEDER, UE) . NC would like to thank the University of the Basque Country forfunding through a specialization of research staff fellowship (ES-PDOC 19/99) . NG acknowledges the funding from the European Union's Horizon 2020 framework programme under the Marie Skodowska-Curie Agreement No. 101028682

Easy-to-Make Polymer Hydrogels by UV-Curing for the Cleaning of Acrylic Emulsion Paint Films

The cleaning of acrylic emulsion paint surfaces poses a great challenge in the conservation field, due to their high water sensitivity. In this article, we present easy-to-make polymer hydrogels, made by UV-photopolymerization, that show excellent cleaning properties. The formulation of hydrogels obtained by UV-curing and their performance as dry cleaners for acrylic paints was investigated. First, different hydrogel formulations based on functional acrylic monomers were used to formulate a series of UV cross-linked hydrogels by fast UV photopolymerization. Their effectiveness on surface dirt removal was investigated by SEM microscopy and colorimetry. The hydrogels showed excellent cleaning properties and controlled water release, and they still performed satisfactorily after several cleaning uses. The obtained UV-hydrogels were compared to the well-known agar gels, showing benefits in terms of reducing excess water. This article shows that easy-to-make UV-cured hydrogels are an efficient tool for the cleaning of surface dirt from water-sensitive paintings, overcoming the limits of traditional cleaning methods.This research was funded by European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant Agreement No. 797295 (eJUMP)

Poly(diallylmethylammonium) proton conducting membranes with high ionic conductivity at intermediate temperatures

High temperature proton exchange membrane fuel cells are being lately investigated because of their high energy efficiency, their superior heat/water management, CO tolerance, and electrode reaction kinetics. To further advance this technology, the polymer membrane portfolio and performance should be improved for intermediate or high temperature operation (>100 °C). In this work we present new poly(diallylmethylammonium) proton conducting membranes with high ionic conductivity at 120 °C. First, new protic ionic liquids, hereafter called DAMAH+X−, were synthesized leading to diallylmethylammonium monomers with different counter-anions. By radical cyclopolymerization through thermal and photoinitiation mechanisms, self-standing protic polymeric membranes of poly(diallylmethylammonium X−) were obtained. Membranes showed good thermal stability (>250 °C) and mechanical properties without the need of additives such as (protic) ionic liquids, solvents or inorganic charges. Great attention was paid to understand the effect of the different counter-anions on the membrane properties. As a general trend, fluorinated anions coming from strong acids confer high ionic conductivity and allow to reduce the hygroscopic properties on the protic polymeric membranes. Proton structural and dynamical stability at different temperatures and humidification conditions were investigated by Neutron Scattering (QENS and NR). The optimized poly(diallylmethylammonium X−) shows similar ionic conductivity values than Nafion 212 under varying relative humidity conditions at 80 °C. Furthermore, it shows a high ionic conductivity value of 1.9 × 10−3 S cm−1 at 120 °C under dry conditions

New poly(ionic liquid)s based on poly(azomethine-pyridinium) salts and its use as heterogeneous catalysts for CO2 conversion

A fast and simple synthetic route towards a new family of poly(ionic liquids) based on aromatic crosslinked poly(azomethine-pyridinium) salts is described. These new polymers were prepared in one step from new diamine methyl pyridinium salts and isopthaldehyde, in 30 min under microwave irradiation. By this method, poly(azomethine-pyridinium) containing chloride (Cl), bis(trifluoromethylsulfonyl)imide (TFSI) and hexaflorophosphate (PF6) as counter-anions were synthetized. This new pyridinium poly(ionic liquid)s were obtained as insoluble powders showing high thermal stability. The poly(azomethine-pyridinium)s were tested as heterogeneous catalysts in the cycloaddition of CO2 to epichlorohydrin to obtain chloropropylene carbonate. The polymers containing chloride anion shows high content of catalytically active sites and the best performance of the series, with 100% selectivity towards the chloropropylene carbonate in a reaction without solvent at 3 bar of CO2, 100 °C and low catalyst loading (0.5 mol%).Spanish Government, MINECO (Projects MAT2014-52085-C2-2-P and MAT2017-82288-C2-2-P, MAT2017-83373-R