Ionic liquids are room-temperature molten salts, composed mostly of organic ions that may undergo almost unlimited structural variations. This review covers the newest aspects of ionic liquids in applications where their ion conductivity is exploited; as electrochemical solvents for metal/semiconductor electrodeposition, and as batteries and fuel cells where conventional media, organic solvents (in batteries) or water (in polymer-electrolyte-membrane fuel cells), fail. Biology and biomimetic processes in ionic liquids are also discussed. In these decidedly different materials, some enzymes show activity that is not exhibited in more traditional systems, creating huge potential for bioinspired catalysis and biofuel cells. Our goal in this review is to survey the recent key developments and issues within ionic-liquid research in these areas. As well as informing materials scientists, we hope to generate interest in the wider community and encourage others to make use of ionic liquids in tackling scientific challenges.

Ionic-liquid materials for the electrochemical challenges of the future.

Conducting-polymer-based supercapacitor devices and electrodes

The widespread use of controlled molecular-level motion in key natural processes suggests that great rewards could come from bridging the gap between the present generation of synthetic molecular systems, which by and large rely upon electronic and chemical effects to carry out their functions, and the machines of the macroscopic world, which utilize the synchronized movements of smaller parts to perform specific tasks. This is a scientific area of great contemporary interest and extraordinary recent growth, yet the notion of molecular-level machines dates back to a time when the ideas surrounding the statistical nature of matter and the laws of thermodynamics were first being formulated. Here we outline the exciting successes in taming molecular-level movement thus far, the underlying principles that all experimental designs must follow, and the early progress made towards utilizing synthetic molecular structures to perform tasks using mechanical motion. We also highlight some of the issues and challenges that still need to be overcome.

Synthetic molecular motors and mechanical machines.

A surgical stapling device particularly suited for endoscopic procedures is described The device includes a handle assembly and an elongated body extending distally from the handle assembly The distal end of the elongated body is adapted to engage a disposable loading unit A control rod having a proximal end operatively connected to the handle assembly includes a distal end extending through the elongated body A control rod locking member is provided to prevent movement of the control rod until the disposable loading unit is fully secured to the elongated body of the stapling device

Surgical Stapling Apparatus

2.5. Stabilization of IL Emulsions by Nanoparticles 2623 3. Hydrogenations in ILs 2623 3.1. Hydrogenation on IL-Stabilized Nanoparticles 2623 3.1.1. Hydrogenation of 1,3-Butadiene 2623 3.1.2. Hydrogenation of Alkenes and Arenes 2624 3.1.3. Hydrogenation of Ketones 2624 3.2. Homogeneous Catalytic Hydrogenation in ILs 2624 3.3. Hydrogenation of Functionalized ILs 2625 3.3.1. Selective Hydrogenation of Polymers 2625 3.4. Asymmetric Hydrogenations 2626 3.4.1. Enantioselective Hydrogenation 2626 3.5. Role of the ILs Purity in Hydrogenation Reactions 2628

Catalysis in ionic liquids

π-Conjugated polymers that are electrochemically cycled in ionic liquids have enhanced lifetimes without failure (up to 1 million cycles) and fast cycle switching speeds (100 ms). We report results for electrochemical mechanical actuators, electrochromic windows, and numeric displays made from three types of π-conjugated polymers: polyaniline, polypyrrole, and polythiophene. Experiments were performed under ambient conditions, yet the polymers showed negligible loss in electroactivity. These performance advantages were obtained by using environmentally stable, room-temperature ionic liquids composed of 1-butyl-3-methyl imidazolium cations together with anions such as tetrafluoroborate or hexafluorophosphate.

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Use of Ionic Liquids for π-Conjugated Polymer Electrochemical Devices

Electrochemical synthesis of conjugated polymers in ionic liquids, achievement of electroactivity and electrochroism of conjugated polymers in ionic liquids, and the use of the resulting conjugated polymers for the fabrication of electrochromic devices incorporating ionic liquids (28) as electrolytes are described.

Stable conjugated polymer electrochromic devices incorporating ionic liquids

Electrolytes play an important role in determining the performance of conducting polymer electrochromic devices. Good electrolytes should have high conductivity, large electrochemical windows, excellent thermal and chemical stability, and negligible evaporation. Room-temperature ionic liquids are ideal electrolytes to satisfy these requirements. In the present work, we explored the applications of ionic liquids as electrolytes in electrochemical synthesis of conducting polymers, in electrochemical and electrochromic characterization of both electrochemically and chemically synthesized conducting polymers and in fabrication of conducting polymer electrochromic devices. In ionic liquids, highly stable electroactivity has been obtained for polyaniline in a wide potential range covering its entire redox process of for >1,000,000 cycles. During the fabrication of electrochromic devices, electrochemically synthesized polymers were employed for displays, while chemically synthesized polymers (via spin-coating) were preferable for large-area electrochromic windows. We have successfully fabricated the prototypes of alphanumeric displays and large-area electrochromic windows. High device performance of low operation voltages ( 50%), fast coloration speed ( 98%) has been realized. © 2004 The Electrochemical Society. All rights reserved.

https://iopscience.iop.org/article/10.1149/1.1640635/pdf

Fabricating Conducting Polymer Electrochromic Devices Using Ionic Liquids

The electrochemical linear actuation of polyaniline fiber actuators has been studied in a variety of acidic aqueous electrolytes. Experimental results show that the linear strain changes significantly but nonlinearly with the anion volume. For anions smaller than Br-, a larger strain was obtained for a larger anion, that is, Br- > Cl- > F-, while once the anion was larger than Br-, a larger anion produced a smaller strain, that is, BF4- > ClO4- > CF3SO3-. On the basis of the definition of the ECR (elongation/charge ratio), that is, the contribution of a unit charge to fiber elongation, the maximum linear strain can be estimated by assuming the electrochemical efficiency is 100%. Furthermore, under isotonic conditions and the application of a constant voltage, the energy efficiency without energy recovery was shown to be proportional to the ECR and applied force and inversely proportional to the applied voltage. Under the same conditions, the highest energy efficiency is obtained in HBr. By assuming that ion and solvent insertion contributes mostly to the fiber expansion, a simple mathematical description is developed for the linear strain to show how it is determined by the volume and carried charge of the insert complex and the anisotropicity of the fiber. The difference between the theoretical and experimental results suggests that due to the crystallite structure, not all exchanged charge contributes to the fiber expansion. As the anion becomes larger, it may become more difficult for the anions to be inserted into the polymer fiber.

Strain and energy efficiency of polyaniline fiber electrochemical actuators in aqueous electrolytes.

The present invention includes the use of conducting polymers as sensors in distributed sensing systems, as sensors and operating elements in multifunctional devices, and for conducting-polymer based multifunctional sensing fabrics suitable for monitoring humidity, breath, heart rate, blood (location of wounds), blood pressure, skin temperature, weight and movement, in a wearable, electronic embedded sensor system, as examples. A fabric comprising conducting polyaniline fibers that can be used to distribute energy for resistive heating as well as for sensing the fabric temperature is described as an example of a multifunctional sensing fabric.

Baohua Qi

Papers

Use of Ionic Liquids for π-Conjugated Polymer Electrochemical Devices

Stable conjugated polymer electrochromic devices incorporating ionic liquids

Fabricating Conducting Polymer Electrochromic Devices Using Ionic Liquids

Strain and energy efficiency of polyaniline fiber electrochemical actuators in aqueous electrolytes.

Multifunctional conducting polymer structures