No description available.

A simple and feasible method of computer colour matching involving fluorescent dyes was developed. An ordinary abridged-spectroreflectometer with polychomatic illumination and a simulated D65 xenon light source was employed for all measurements. In addition to the normal K/S constants for non-fluorescent dyes and the non-fluorescent portion of the fluorescent dye'.. constants responsible for the fluorescent portion were necessary. Two sets of equations to relate the total radiance factors of dyeings with a fluorescent dye and its concentration were developed respectively for self and compound shades where a non-fluorescent dye is admixed. Finding constants responsible for the compound shades required a number of calibration mixture dyeings. Negative K/S constants were found useful when the total radiance factor was above that for the substrate but below one hundred. Three computer programs? s were developed to deal with calibration constants for self and compound shade and also for match prediction. Optimization was used in all cases to minimize errors in total radiance factors or colour differences. Half of the actual dyeingq formulations from the predicted were visually passed by a panel of five dyers. In this study, disperse dyes on polyester were used. Moreover, a commercial matching package was studied using non-fluorescent dyes. The dyeing system affected its accuracy. The polyester/disperse dye system was better than the cotton/reactive dye system. The sample size and luminancefactor of target colours; were also studied. The accuracy was affected slightly by the latter but not the former.

No description available.

The work in this thesis is primarily aimed at supporting the NBe (Nuclear, Biological and Chemical) aspect of Crusader 21, the military clothing programme for the early 21st Century. This aims to produce a multi-purpose, systems-orientated combat ensemble for the UK Armed Services. Conventional "wet" techniques for chemically modifying fabrics have certain disadvantages, however employing plasma technology may provide a route for many novel "multi-functional effects" fabrics such as repellency against toxic chemical agents. In order to produce repellent coatings the surface must have a low surface energy. To obtain this, inert chemical groups need to be attached to the solid substrate. In addition to chemistry, surface roughness plays an important role in repellency. Liquid repellent surfaces have been produced by the pulsed plasma polymerisation of I H, 1 H,2H,2H -heptadecafluorodecyl acrylate. These films have chemical functionalities indicative of polymerisation occurring through the acrylate double bond, as shown by Infrared Spectroscopy analysis. Structural retention was optimised using experimental design techniques and resulted in a critical surface tension of wetting as low as 4.3 mN m-I (c.f. Teflon 18.5 mN m-I). Plasma deposition of a functionalised surface followed by reaction with a fluorinated alcohol proved less affective. Enhanced deposition rates for 1 H, 1 H,2H-perfluorododec-I-ene, over the saturated analogue, have indicated that polymerisation can occur during the off-time of the pulsed plasma period, via free radical polymerisation pathways. X-ray Photoelectron Spectroscopy (XPS) has indicated greater structural group retention for monomers containing double bonds. In order to obtain super liquid repellency the effect of surface roughness was investigated, where both commercially available rough surfaces and plasma roughened substrates were utilised. Once optimised, the rough surfaces were coated with 1 H, 1 H,2H,2H-heptadecafluorodecyl acrylate and produced super repellent films.

No description available.

No description available.

No description available.

A study and comparison of two commercially available and competitive physical vapour deposition techniques has been made. Titanium nitride (the most widely used hard and decorative coating) has been deposited by both steered arc and the new Arc Bond Sputter (ABS) magnetron technique under a range of deposition conditions. The coatings have subsequently been analysed by a variety of methods and the results reported here. The steered arc technique has been identified as the better technique for everyday ease of use in producing mononitride and monocarbide coatings with good batch uniformity and reproducibility in terms of composition and microstructure. However, for versatility the ABS magnetron technique allows the possibility to vary multiple parameters and hence change coating properties at will, albeit with some difficulty to maintain stable and reproducible operation. In this respect, plasma uniformity is discussed and problems with water vapour contamination and gas flow regulation are highlighted and possible solutions suggested. The coating-substrate interface region is considered, and the merits of metallic interlayers and arc etching are compared. An interlayer achieves good adhesion only at an optimum thickness as confirmed in this work. The good adhesion afforded by the arc etch phase of both processes is addressed and the ion-surface interactions modelled using commercially available computer software. The improvement in adhesion on high speed steel is explained by sputtering of the substrate matrix leaving hard carbide particles standing proud of the surface. When deposition takes place, the carbides mechanically key the coating to the substrate surface, and also possibly act as physical blocks to interfacial crack propagation. A theoretical contribution to the explanation of preferred crystallographic orientation during coating deposition is proposed derived from experimental results, surface physics and semiconductor growth theory. This attempts to explain the flexibility of sputtering techniques to produce a wide range of orientations, and the reasons why arc evaporation almost always produces {111} orientated coatings. Finally, a consideration of a comparatively new analytical technique (Glow Discharge Optical Emission Spectroscopy) to the application of PVD coatings evaluation is addressed. The speed and versatility of this technique makes it strategically important in the future research, development and quality control of thin film production.

No description available.

No description available.