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The effects of surfactants on the dynamics and characteristics of plain and composite electroless nickel plating (ENP) are highlighted and discussed herein. An outline of the rudiments of surfactants and some underlying selection criteria is presented at the outset, before emphasis is laid on the salient benefits of introducing such external agents during the plating process. Evidence suggests that their influence on key coating characteristics such as the rate of deposition, structure, corrosion resistance, and the degree of second-phase particle incorporation into the nickel matrix is significant, and depending on the nature and concentration of surfactant employed, can be of immense value to the system.

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While flexible-leaflet, central-flow prosthetic heart valves promise relief from anticoagulation therapy, they continue to be restricted by inadequate durability. In consequence, a novel trileaflet valve, made entirely from polyurethane, has been developed. A batch of 6 consecutively manufactured polyurethane valves was subjected to hydrodynamic function and accelerated fatigue testing. Computerized data acquisition and control systems have been introduced to improve valve testing methodologies. In terms of hydrodynamic function, the polyurethane valve demonstrates transvalvular pressure gradients similar to those for a bioprosthetic valve (Carpentier-Edwards) and levels of retrograde flow significantly less than those for either the bioprosthetic valve or a bileaflet mechanical valve (St Jude Medical). The equivalent of 10 years of cycling without failure has been exceeded by all 6 polyurethane valves in accelerated fatigue tests with 2 valves remaining intact after 674 million cycles (equivalent to approximately 17 years) in continuing tests. Highspeed photography revealed considerable differences in leaflet motion between valves cycled at accelerated and physiological rates.

The influence of a surfactant on the composition of nickel-yttria stabilised zirconia (YSZ) cermet coatings, applied by electroless nickel plating technique was examined. The amphiphilic characteristics of anionic surfactant sodium dodecyl sulphate (SDS), was relied upon for enhanced dispersion of YSZ particles co-deposited for use as anodes in solid oxide fuel cell technology and potential heat absorbing layers in thermal barrier coatings. Optical microscopy was employed to study the correlation between the plating thickness, level of ceramic loading and SDS concentration while the effect of the surfactant and fineness of YSZ particles on the as-deposited coating's ceramic to metal ratio, was analysed using energy dispersive X-ray analysis (EDXA) characterisation technique.