Cross-linked polymers constructed with dynamic-covalent boronic esters were synthesized via photoinitiated radical thiol–ene click chemistry. Because the reversibility of the boronic ester cross-links was readily accessible, the resulting materials were capable of undergoing bond exchange to covalently mend after failure. The reversible bonds of the boronic esters were shown to shift their exchange equilibrium at room temperature when exposed to water. Nevertheless, the materials were observed to be stable and hydrophobic and absorbed only minor amounts of water over extended periods of time when submerged in water or exposed to humid environments. The facile reversibility of the networks allowed intrinsic self-healing under ambient conditions. Highly efficient self-healing of these bulk materials was confirmed by mechanical testing, even after subjecting a single site to multiple cut–repair cycles. Several variables were considered for their effect on materials properties and healing, including cross-link density, humidity, and healing time.

Networks that contain boronic ester crosslinks undergo dynamic bond exchange that enables self-healing behavior and reprocessing.

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A mixture of the ionic liquids 1-ethyl-3-methylimidazolium bis͑trifluoromethanesulfonyl͒imide ͑EMIBTI͒ and 1-ethyl-3-methylimidazolium hexafluorophosphate ͑EMIPF6͒ was formulated. The thermal properties of the 50/50 binary mixture were determined by differential scanning calorimetry and cloud point measurement. No evidence of crystallization or phase separation during cooling at 1°C/min to − 60°C was found. The devices constructed in this study were light weight, flexible, and hermetically sealed. These sealed devices proved effective against electrolyte leakage and performance degradation during temperature cycling. The performance of poly͑propylenedioxy͒ thiophene ͑PProDOT͒-based type I supercapacitors using a 50/50 wt % EMIBTI/EMIPF6 electrolyte mixture was compared to the performance using neat EMIBTI. It was difficult to deposit PProDOT films directly from the ionic liquid mixtures. However, it was possible to deposit PProDOT films from EMIBTI and then assemble and test the devices using the 50/50 mixture. The low temperature performance of the EMIBTI/EMIPF6 supercapacitors was superior to that of the EMIBTI-based supercapacitors, evidenced by the retention of capacitive behavior below −30°C. The high temperature performance of the EMIBTI/EMIPF6 supercapacitors was nearly as good as the EMIBTI-based supercapacitors with 10% loss after 10,000 cycles at 70% depth of discharge at 60°C.Electroactive polymer devices, in which the polymers switch between redox states to store charge, have been the object of concentrated research over the past several years. As these polymers have the possibility of being switched between their neutral form, a p-type doped oxidized form, and an n-type doped reduced form, a variety of electrode configurations are possible. This has been exemplified by the use of electroactive polymers in supercapacitors, 1 rechargeable storage batteries, 2 and electrochromic devices. 3,4 The poly͑3,4-alkylenedioxythiophenes͒ ͑PXDOTs͒ 5 have especially useful redox switching properties due to their electron-rich character, which yields especially low switching potentials. The parent polymer of this family, poly͑3,4-ethylenedioxythiophene͒, has now been developed to the point of commercialization ͑Baytron P, Bayer AG͒ and is used as a stable conducting material in photographic film, tantalum capacitors, and feed-through holes in printed circuit boards. 6 In addition, these polymers switch rapidly and efficiently between their neutral and p-doped forms with a minimum of side reactions and long switching lifetimes. As such, they have been heavily investigated for a number of redox devices including electrochromic applications. 7 Polymeric supercapacitors using PXDOTs as the charge carrying layer exhibit excellent reversibility and coulombic efficiency. 8,9 It is well known that changes in redox states of electroactive polymers require movement of ions to maintain electroneutrality. Ion choice can affect morphology, stability, and oxidation and reduction potentials. 10 Ions have traditionally been introd...