Surface finish ionic

The majority of aqueous plating solutions are supplied as finished products by major distribution suppliers. No such analogue exists for ionic liquids as no plating processes have been developed with a sufficiently good surface finish to replace the aqueous competitor. A number of companies make or distribute ionic liquids on the > 100kg scale. These include BASF, Merck, Scionix and Solvent Innovation although laboratory scale amounts can now be obtained from a wide range of chemical supply houses. 

The absorption of species from the atmosphere is common to all electrolyte solutions and clearly the absorption of water is the biggest issue. This is not solely confined to ionic liquids, however, as all electroplaters who deal with aqueous solutions of acids know, if the solution is not heated then the tank will overflow from absorption of atmospheric moisture after some time. In the aqueous acid the inclusion of water is not a major issue as it does not significantly affect the current efficiency or potential window of the solution. Water absorption is also not such a serious issue with eutectic-based ionic liquids and the strong Lewis acids and bases strongly coordinate the water molecules in solution. The presence of up to 1 wt.% water can be tolerated by most eutectic-based systems. Far from having a deleterious effect, water is often beneficial to eutectic-based liquids as it decreases the viscosity, increases the conductivity and can improve the rate of the anodic reaction allowing better surface finishes. Water can even be tolerated in the chloroaluminate liquids to a certain extent [139] and it was recently shown that the presence of trace HQ, that results from hydrolysis of the liquid, is beneficial for the removal of oxide from the aluminum anode [140]. 

Scionix has developed an alternative concept to forming eutectic-based ionic liquids which is to complex the anion of choline chloride with a hydrogen-bonding compound rather than a metal halide [21,22]. The ionic liquids allow electropolishing with high current efficiency (>80%), improved surface finish and improved corrosion resistance [23]. 

Fig. 8.12 Examples of hard chromium electroplating for engineering applications, (a) A printing roll following grinding and polishing, a smooth and highly reflecting surface finish is possible, (b) An injection moulding tool used to produce plastic water tanks (Photographs courtesy Ionic Surface Treatments Plating by Hilton and Tuck Division, Manchester.)...

Tsuda, T., Hussey, C. L. Stafford, G. R. (2007). Progress in Surface Finishing with Lewis Acidic Room-Temperature Chloroaluminate Ionic Liquids, ECS Trans., 3(35) 217-231. 

Over time, finish components tend to separate and migrate within the fiber and throughout the yam package. With nylon, the ionic emulsifiers and antistats tend toward the core of the fiber whereas the hydrocarbon lubricants remain on the surface. It is, therefore, essential to scour yams and fabrics at neutral to basic pH to reemulsify the lubricant and remove the finish emulsifier prior to dyeiag. In formulating any new finish, environmental issues such as biodegradabihty, water and air pollution must be considered (137). 

Control of fiber friction is essential to the processing of fibers, and it is sometimes desirable to modify fiber surfaces for particular end-uses. Most fiber friction modifications are accomplished by coating the fibers with lubricants or finishes. In most cases, these are temporary treatments that are removed in final processing steps before sale of the finished good. In some cases, a more permanent treatment is desired, and chemical reactions are performed to attach different species to the fiber surface, e.g. siliconized slick finishes or rubber adhesion promoters. Polyester s lack of chemical bonding sites can be modified by surface treatments that generate free radicals, such as with corrosive chemicals (e.g. acrylic acid) or by ionic bombardment with plasma treatments. The broken molecular bonds produce more polar sites, thus providing increased surface wettability and reactivity. 

We begin with a discussion of the most common minerals present in Earth s crust, soils, and troposphere, as well as some less common minerals that contain common environmental contaminants. Following this is (1) a discussion of the nature of environmentally important solid surfaces before and after reaction with aqueous solutions, including their charging behavior as a function of solution pH (2) the nature of the electrical double layer and how it is altered by changes in the type of solid present and the ionic strength and pH of the solution in contact with the solid and (3) dissolution, precipitation, and sorption processes relevant to environmental interfacial chemistry. We finish with a discussion of some of the factors affecting chemical reactivity at mineral/aqueous solution interfaces. 

Most non-polymeric antistatic finishes are also surfactants that can orient themselves in specific ways at fibre surfaces. The hydrophobic structure parts of the molecule act as lubricants to reduce charge buildup. This is particularly true with cationic antistatic surfactants that align with the hydrophobic group away from the fibre surface, similar to cationic softeners (see Chapter 3, Fig. 3.1). The main antistatic effect from anionic and non-ionic surfactants is increased conductivity from mobile ions and the hydration layer that surrounds the hydrophilic portion of the molecule since the surface orientation for these materials places the hydrated layer at the air interface. 

An accurate description of the processes that result in the binding of ionic ligands to substrates used for catalyst supports is a requisite step to develop a basis for catalyst preparation. Few will dispute that strong binding of catalytic precursor ions to catalyst supports will result in a resistance to sintering and a higher dispersion of the active phase. If the view of electrostatic attraction between the catalytic precursor ion and the charge present on the surface is accepted, then the chemically induced/spatially defined architecture present on the support becomes the "traffic cop" which directs the potential fate of the structure of the finished catalyst. 

Fig. 8.20 Applications of electroless nickel plating Ni-P deposits for wcar>resistant and corrosion-resistant applications in engineering, (a) A cooling-cail assembly. (Photo graphy courtesy Ionic Surface Treatments plating by Dudley Division.) (b) Printed circuit boards for a wrist watch and calculators. Electrically isolated areas of deposited copper may be built up by electroless nickel plating which also provides a corrosion-resistant and solderablc finish. The deposits are various NIKLAD electroless nickels. (Photograph Courtesy Lea Manufacturing.)...

Antistatic Finishes Owing to its hydrophobicity, polyester builds up static charge readily. Finishes have been developed for polyester that increase the hydrophilicity and ionic character of the fiber and permit more ready dissipation of static charge from the fiber surface. These treatments include lauryl phosphate, morpholine, various polyethylene glycols, organosilicones, and polyamine resins. 

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