Direct Observation of Ion Distributions near Electrodes in Ionic Polymer Actuators Containing Ionic Liquids

Liu, Yang; Lu, Chin-Pi; Twigg, Stephen; Ghaffari, Mehdi; Lin, Jixing; Winograd, Nicholas; Zhang, Q. M.

doi:10.1038/srep00973

Cited by 45 publications

(57 citation statements)

References 35 publications

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“…The reactor was then vented, opened at ambient condition, and the ionic liquid was immediately introduced into a SALVI device for ToF-SIMS analysis. It should be noted that many ionic liquids have very low vapor pressure and they can be directly analyzed using regular ToF-SIMS [23][24][25][26]. The DBU-base switchable ionic liquid is unique because it decomposes to release CO 2 under vacuum (as shown in Scheme 1 [20]).…”

Section: Sample Preparationmentioning

confidence: 99%

Improving the Molecular Ion Signal Intensity for In Situ Liquid SIMS Analysis

Zhou

Yao

Ding

et al. 2016

J. Am. Soc. Mass Spectrom.

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Abstract. In situ liquid secondary ion mass spectrometry (SIMS) enabled by system for analysis at the liquid vacuum interface (SALVI) has proven to be a promising new tool to provide molecular information at solid-liquid and liquid-vacuum interfaces. However, the initial data showed that useful signals in positive ion spectra are too weak to be meaningful in most cases. In addition, it is difficult to obtain strong negative molecular ion signals when m/z>200. These two drawbacks have been the biggest obstacle towards practical use of this new analytical approach. In this study, we report that strong and reliable positive and negative molecular signals are achievable after optimizing the SIMS experimental conditions. Four model systems, including a 1,8-diazabicycloundec-7-ene (DBU)-base switchable ionic liquid, a live Shewanella oneidensis biofilm, a hydrated mammalian epithelia cell, and an electrolyte popularly used in Li ion batteries were studied. A signal enhancement of about two orders of magnitude was obtained in comparison with non-optimized conditions. Therefore, molecular ion signal intensity has become very acceptable for use of in situ liquid SIMS to study solid-liquid and liquid-vacuum interfaces.

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Section: Sample Preparationmentioning

confidence: 99%

Improving the Molecular Ion Signal Intensity for In Situ Liquid SIMS Analysis

Zhou

Yao

Ding

et al. 2016

J. Am. Soc. Mass Spectrom.

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“…With the ability to operate in an aqueous environment and mimic closely the motion of biological muscles, IPMC materials are particularly attractive in the field of biomimetics, including underwater robotics, artificial muscles, and biomedical and human affinity applications, such as microsensors and active catheters234567.…”

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confidence: 99%

Nanothorn electrodes for ionic polymer-metal composite artificial muscles

Palmre

Pugal

Kim

et al. 2014

Sci Rep

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Ionic polymer-metal composites (IPMCs) have recently received tremendous interest as soft biomimetic actuators and sensors in various bioengineering and human affinity applications, such as artificial muscles and actuators, aquatic propulsors, robotic end-effectors, and active catheters. Main challenges in developing biomimetic actuators are the attainment of high strain and actuation force at low operating voltage. Here we first report a nanostructured electrode surface design for IPMC comprising platinum nanothorn assemblies with multiple sharp tips. The newly developed actuator with the nanostructured electrodes shows a new way to achieve highly enhanced electromechanical performance over existing flat-surfaced electrodes. We demonstrate that the formation and growth of the nanothorn assemblies at the electrode interface lead to a dramatic improvement (3- to 5-fold increase) in both actuation range and blocking force at low driving voltage (1–3 V). These advances are related to the highly capacitive properties of nanothorn assemblies, increasing significantly the charge transport during the actuation process.

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“…The discovery of nanoporous electrode materials with enhanced capacitive performances when using an ionic liquid with ion sizes matching the pore size, as illustrated in Figure 1, opens the way for a widespread use of supercapacitors in many contexts where high power electrical output is required 14 . As an extension, the behavior of the ionic liquids at charged interfaces even allows one to forecast the development of electroactuators 15,16 which could be used as artificial muscles, sensors, and even energy generators in turbulent flows or sea-tide.…”

mentioning

confidence: 99%

Computer simulations of ionic liquids at electrochemical interfaces

Merlet¹,

Rotenberg²,

Madden³

et al. 2013

Phys. Chem. Chem. Phys.

155

188

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Ionic liquids are widely used as electrolytes in electrochemical devices. In this context, many experimental and theoretical approaches have been recently developed for characterizing their interface with electrodes. In this perspective article, we review the most recent advances in the field of computer simulations (mainly molecular dynamics). A methodology for simulating electrodes at constant electrical potential is presented. Several types of electrode geometries have been investigated by many groups, in order to model planar, corrugated and porous materials and we summarize the results obtained in terms of the structure of the liquids. This structure governs the quantity of charge which can be stored at the surface of the electrode for a given applied potential, which is the relevant quantity for the highly topical use of ionic liquids in supercapacitors (also known as electrochemical double-layer capacitors). A key feature, which was also shown by atomic force microscopy and surface force apparatus experiments, is the formation of a layered structure for all ionic liquids at the surface of planar electrodes. This organization cannot take place inside nanoporous electrodes, which results in a much better performance for the latter in supercapacitors. The agreement between simulations and electrochemical experiments remains qualitative only though, and we outline future directions which should enhance the predictive power of computer simulations. In the longer term, atomistic simulations will also be applied to the case of electron transfer reactions at the interface, enabling the application to a broader area of problems in electrochemistry, and the few recent works in this field are also commented upon.

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Direct Observation of Ion Distributions near Electrodes in Ionic Polymer Actuators Containing Ionic Liquids

Cited by 45 publications

References 35 publications

Improving the Molecular Ion Signal Intensity for In Situ Liquid SIMS Analysis

Improving the Molecular Ion Signal Intensity for In Situ Liquid SIMS Analysis

Nanothorn electrodes for ionic polymer-metal composite artificial muscles

Computer simulations of ionic liquids at electrochemical interfaces

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