Karl Ryder

Eutectic based ionic liquids containing choline chloride are shown to be useful for electrochemical applications that currently use aqueous solutions. It is shown that an ionic liquid composed of ethylene glycol (HOCH2 CH2 OH) and choline chloride (HOC2 H4 N(CH3 )3 + Cl˙) offers ...

... pilot plants from IONMET consortium EL Smith*, C. Fullarton, RC Harris, S. Saleem, APAbbott and KS Ryder ... The results of surface characterisation of a stainless steel sheet before and after electropolishing in the IL bath can be seen in Fig. ...

Characterization of electroactive polymer films and their application in practical devices (electronic, chemical, sensing, energy storage, optical, actuator) tends to focus on the transfer of charged species (electrons and counter ions), since these are the entities most directly associated with the response to the electrochemical control function. However, transport rates of ions (“dopant”, in the context of conducting polymer systems) are dictated by solvent content of the film, which governs the local viscosity of the medium through which mobile species move. Further, the presence of solvent (and other small molecules) creates free volume that facilitates the dynamics of polymer motion, macroscopically seen as a plasticising effect on film viscoelasticity. In the light of the above, it is of value to determine the solvent content of electroactive polymer films; this is the focus of the present work. Experimentally, the challenge is that the solvent is (by choice) electrochemically “silent” and optically transparent, and its selective observation within a film exposed to a vast reservoir of bulk solution is not trivial. Nanogravimetric measurements made using the EQCM have provided innumerable insights into changes in film solvent population, e.g. in response to redox state changes, but the technique cannot provide absolute solvent population in the film. Spectroscopic techniques generally have difficulty in distinguishing solvent in a film from that in bulk solution, but reflectivity techniques do possess surface selectivity. Of these, ellipsometry has the advantage of rapid data acquisition, i.e. good time resolution, but modelling the data can present ambiguities. Here we use neutron reflectivity (NR) which, through the penetrating nature of neutrons, allows access to "buried" interfaces. Traditionally, the negative consequence of this weak interaction with matter is long data acquisition times; addressing this is the central feature of this presentation. Since neutrons interact with the nuclei in the system (cf. photons interacting with the electrons in ellipsometry), NR has the huge advantage of isotopic selectivity. This is commonly referred to as “contrast variation” and has the critical characteristic of allowing one to vary the visibility of a selected chemical component without (to a first approximation) altering the (electro)chemistry of the system. Most frequently, this is exploited by deuteration, since the neutron scattering lengths of H and D are very different. Correlation of the h- and d-system NR data sets removes ambiguities in modelling the data.   We have previously used NR with solvent contrast variation to determine solvent volume fraction depth profiles, ΦS(z), in redox polymer films at equilibrium (fixed potential) and on long timescales during slow cycling. We now present data under dynamic conditions more relevant to fabrication or operation of a working device. This necessitates an order of magnitude improvement in time resolution. Instrumentally, the challenge can be met using more sophisticated detection systems, including event mode data capture, in which every incident/reflected neutron is detected individually. The dramatic increase in the size of data sets presents challenges in modelling the data, but the facility to (re-)select signal averaging time post experiment permits optimisation of competing aspirations of time resolution and signal-to-noise. This is key for single shot experiments, such as film deposition or evolution of film behaviour. Here we present neutron reflectivity data for aniline-, pyrrole- and thiophene-based polymer films. For these systems, we have the opportunity to exploit h- and d- variants of both solvent and monomer. Four significant insights are revealed. First, the data reveal that film deposition protocol (i.e. potentiostatic, potentiodynamic or galvanostatic control function) influences film solvation state and spatial distribution; while anecdotally suspected, this provides unambiguous quantitative evidence. Second, there are substantial spatial variations in film solvent content; this is a feature commonly not accommodated in models of modified electrodes. Third, for some systems, film solvent population and spatial disribution are "frozen" into the system during fabrication, so deposition protocol determines film characteristics in the longer term. Fourth, in selected cases the structure evolves with electrochemical manipulation, such that differently prepared films subsequently exposed to the same environment and history evolve to a common solvation profile. The implications of these phenomena for film design and handling are discussed for particular types of application.

Organic and inorganic additives are often added to nickel electroplating solutions to improve surface finish, reduce roughness and promote uniform surface morphology of the coatings. Such additives are usually small molecules and often referred to as brighteners or levellers. However, there have been limited investigations into the effect of such additives on electrodeposition from ionic liquids (ILs) and deep eutectic solvents (DESs). Here we study the effect of four additives on electrolytic nickel plating from an ethyleneglycol based DES; these are nicotinic acid (NA), methylnicotinate (MN), 5,5-dimethylhydantoin (DMH) and boric acid (BA). The additives show limited influence on the bulk Ni(ii) speciation but have significant influence on the electrochemical behaviour of Ni deposition. Small concentrations (ca. 15 mM) of NA and MN show inhibition of Ni(ii) reduction whereas high concentrations of DMH and BA are required for a modest difference in behaviour from the additive free ...

Eutectic based ionic liquids containing choline chloride are shown to be useful for electrochemical applications that currently use aqueous solutions. It is shown that an ionic liquid composed of ethylene glycol (HOCH2 CH2 OH) and choline chloride (HOC2 H4 N(CH3 )3 + Cl˙) offers ...

As is well known in the Ionic Liquids Community 109 to 1018 ionic liquids, binary and ternary mixtures have been predicted to be – theoretically – achievable. Of course, this is an incredible number and it will hardly be possible to synthesize all these liquids and investigate all of ...

Here we describe the electrolytic deposition of a range of metallic coatings, alloys and composites from room temperature ionic liquids that have low environmental impact/toxicity, are inexpensive and easy to handle. We show that some of these systems can be considered as "drop-in" replacement technologies for existing aqueous processes that currently utilize strong inorganic acids and highly toxic reagents.

Between 1980 and about 2000 most of the studies on the electrodeposition in ionic liquids were performed in the first generation of ionic liquids, formerly called “room-temperature molten salts” or “ambient temperature molten salts”. These liquids are comparatively easy to ...

PurposeThe purpose of this paper is to present the optimisation of protocols for the immersion coating of silver onto copper‐track printed circuit board (PCB) assemblies, using a novel class of ionic liquid and to show the implementation of the scale up process.Design/methodology/approachVarious conditions (temperatures and silver concentrations) are studied individually under laboratory conditions and then optimised for a pilot scale demonstrator line that is used to process British Standard test coupons.FindingsThe use of these novel liquids for the immersion coating of silver produces silver dip coatings that are bright and even and which give solderability that is as good as the commercial aqueous, nitric acid based, electroless process without any solder‐mask interface etching.Research limitations/implicationsThe combined technology has been optimised for an immersion silver coating line. Further development work should be undertaken to tailor the technology for gold immersion ...

The deposition of aluminium from a chloroaluminate based ionic liquid was studied to elucidate the effect of a diluent (toluene) and electrolyte (LiCl) on the deposit morphology. A wide variety of analytical techniques was applied to this system to determine the speciation and mechanism of material growth. These included: (27)Al NMR, FAB-MS, cyclic voltammetry, chronocoulometry, chronopotentiometry, scanning electron microscopy and atomic force microscopy. It was found that under-potential deposition (upd) causes a change in the way in which metal grows on the electrode surface. Metal grows in two regimes which are believed to be nano-material and bulk material. The addition of toluene causes a change in speciation and a decrease in upd which in turn changes the morphology of the deposit obtained and can lead to mirror finish aluminium. The addition of LiCl has the opposite effect encouraging upd and leading to larger crystallites and a dark grey deposit. It is also shown for the first time that under many conditions the rate of the anodic dissolution process is overall rate controlling and one effect of the addition of toluene is to increase the rate of anodic dissolution.

The electrodeposition of metals from ionic solutions is intrinsically linked to the reactivity of the solute ions. When metal salts dissolve, the exchange of the anion with the molecular and ionic components from solution affects the speciation and therefore the characteristics of metal reduction. This study investigates the nucleation mechanism, deposition kinetics, metal speciation and diffusion coefficients of silver salts dissolved in Deep Eutectic Solvents. The electrochemical reduction of AgCl, AgNO3 and Ag2O is studied in 1 : 2 choline chloride : ethylene glycol and 1 : 2 choline chloride : urea. Cyclic voltammetry is used to evaluate electrochemical kinetics. Detailed analysis of chronoamperometric data shows that silver deposits form via multiple 3D nucleation with mass transport controlled hemispherical growth. The nucleation mechanism was found to be potential dependent, varying from progressive to instantaneous as the reduction potential becomes more cathodic. Diffusion coefficients are determined using three different methods. Trends are rationalised in terms of solvent viscosity and silver speciation analysis with EXAFS. The morphology of electroreduced silver is investigated with scanning electron microscopy and shows that deposits from the urea based liquid form more dense morphologies than those from the ethylene glycol based liquid.

Silver is an important metal for electronic connectors, however, it is extremely soft and wear can be a significant issue. This paper describes how improved wear resistant silver coatings can be obtained from the electrolytic deposition of silver from a solution of AgCl in an ethylene glycol/choline chloride based Deep Eutectic Solvent. An up to 10-fold decrease in the wear volume is observed by the incorporation of SiC or Al(2)O(3) particles. The work also addresses the fundamental aspect of speciation of silver chloride in solution using EXAFS to probe solution structure. The size but not the nature of the composite particles is seen to change the morphology and grain size of the silver deposit. Grain sizes are shown to be consistent with previous nucleation studies. The addition of LiF is found to significantly affect the deposit morphology and improve wear resistance.

We demonstrate the first practical alternative to the use of phosphoric and sulphuric acid mixtures for the electropolishing of stainless steel. In this paper, efficient electropolishing of type 316 stainless steel is demonstrated in an ionic liquid composed of ethylene glycol (HOCH 2 CH 2 OH) ...

This study has shown for the first time that digital holographic microscopy (DHM) can be used as a new analytical tool in analysis of kinetic mechanism and growth during electrolytic deposition processes. Unlike many alternative established electrochemical microscopy methods such as probe microscopy, DHM is both the noninvasive and noncontact, the unique holographic imaging allows the observations and measurement to be made remotely. DHM also provides interferometric resolution (nanometer vertical scale) with a very short acquisition time. It is a surface metrology technique that enables the retrieval of information about a 3D structure from the phase contrast of a single hologram acquired using a conventional digital camera. Here DHM has been applied to investigate directly the electro-crystallization of a metal on a substrate in real time (in situ) from two deep eutectic solvent (DES) systems based on mixture of choline chloride and either urea or ethylene glycol. We show, using electrochemical DHM that the nucleation and growth of silver deposits in these systems are quite distinct and influenced strongly by the hydrogen bond donor of the DES.

Here we describe the electrolytic deposition of Zn, Sn and Zn/Sn alloys from a solution of the metal chloride salts separately in urea and ethylene glycol/choline chloride based ionic liquids. We show that the deposition kinetics and thermodynamics differ from the aqueous ...

The addition of a simple amide to AlCl(3) causes the formation of a liquid of the form [AlCl(2)·nAmide](+) AlCl(4)(-). The material thus produced is liquid over a wide temperature range, is relatively insensitive to water and has the properties of an ionic liquid. This ionic liquid is shown to be a suitable medium for the acetylation of ferrocene and the electrodeposition of aluminium and demonstrated that quaternary ammonium cations are not always needed to form ionic liquids.

Two fully hydrated pure-species phospholipids bilayers, 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dioleoyl-sn-glycero-3-phosphorylcholine (DOPC), in the fluid phase and explicit solvent have been studied using molecular dynamics simulation. Atom interactions were modeled using recently developed force fields based on AMBER with full atomistic details. Several representative liquid phase properties for the structure and dynamics of lipids with different length of hydrocarbon chains and different level of saturation have been reproduced without artificially biasing the system in order to match experimental data. In particular, as the new GAFF (General Amber Force Field) has not been explicitly developed to reproduce lipid characteristics and is naturally compatible with standard AMBER nucleic acids and proteins parameters, it is here proven a promising tool to study mixed lipid-protein processes as protein activity dependence on membrane composition, permeation of solute across membranes, and other cellular processes.