Methods were developed for application of thermochromic pigments to textiles, based on printing and extrusion, for both leuco dye based and cholesteric liquid crystal thermochromics. The leuco dye based thermochromics were assessed in terms of heat stability, binder optimization and colour saturation using an instrumental colour measurement system. Enhancement of lightfastness of leuco dye based thermochromics was carried out using UV absorbers, HALS and antioxidants as additives. A comparative study was also carried out between printing and extrusion application methods. A colour measurement system with the facility for temperature variation was constructed using two traditional components – a reflectance spectrophotometer and a controllable hot stage. The dynamic colour change of leuco dye based thermochromics with temperature was assessed. The liquid crystals were assessed with temperature for their additive colour mixing properties by layering them over each other. They were also assessed in terms of aspects of applications, such as differences in the over-layering sequence and colour hysteresis on heating and cooling. The results were evaluated not only to provide a scientific understanding of the performance but also to provide useful information from a creative designer’s point of view. The research carried out as described in this thesis has established an improved understanding of the application methods for leuco dye based and liquid crystal thermochromic pigments for optimum performance. The availability and selection of colours achievable with liquid crystal thermochromics have been widened significantly by the improved understanding of the colours derived from over-layered liquid crystals. It is anticipated that this research will broaden the potential for use of leuco dye based and liquid crystal thermochromics in textiles, especially in the fields of functional textiles and creative design.

Knife is the most commonly used single weapon in the UK, being 32% of the weapons employed in a violent incident. Studies reveal that majority (63.3%) of the knife inflicted wounds were slash type and could be disfiguring or life threatening if the blood vessels are ruptured. The stab resistant armours that are currently available do not protect the arms, neck and face as they are very rigid and heavy to be worn comfortably for everyday use for security personnel and are also expensive for the civilian population. During the research programme, various composite yarns consisting of; a) blends of Spectra® (Ultra High Molecular Weight Polyethylene), glass and polyamide; b) Stainless steel core with wraps of Dyneema® (Ultra High Molecular Weight Polyethylene) and polyester; and c) Kevlar®, in different compositions, were thoroughly investigated to determine the most appropriate yarn for the slash proof materials. The slash proof fabric structures were developed by using knitting technology as it offers significant advantages in terms of cost, design flexibility and versatility. Different fabrics using the appropriate yarn were developed using various knitting criteria. Since there was neither any literature published for slash resistant fabrics nor any comparable fabric availability, the developed fabrics were tested against each other using a test method stipulated for slash proof application. The fabrics were also tested for their thermophysiological and flame resistant properties using a wide range of test methods and procedures. Due to the probable application of slash resistant fabrics, i.e. outer wear in open atmosphere, the developed fabrics were also characterized after exposing 5 years equivalent of UVA/B radiation. This research programme has led to some extremely successful and innovative outcomes including the granting of a full patent. One of the major findings has been that a two-layered knitted structure produced by using a combination of composite and staple-fibre aramid yarns helps to withstand a higher impact force during the slash attack. It was also established that the designed racked structure in the fabric not only provides resistance to the continuous movement of the knife blade but also increases the overall slash resistance capability of the protective fabric. The research has also led to some recommendations for further work in order to re-confirm some of the findings established during the study and also to improve the structure by reducing the area density of the slash resistant fabrics further due to the changes in the pass criteria of the slash resistant standard, set as a direct outcome of this research.

No description available.

In recent years, there has been an increase in studies about developing photovoltaic fabrics which can be used in different textile and clothing applications. The flexibility of the solar cells could be useful in many applications, for example providing power for small portable electronic devices such as personal digital assistants or on a larger scale for sunshades and canopies. In this work, we have taken the direct approach to deposit amorphous silicon cells directly onto fabrics. To achieve that, we have studied approaches to obtaining flexible conductive surfaces on polyester fabrics by using a double layer of metal and commercially available conductive polymer. Then both single and stacked metal contact layers and thin amorphous silicon films were built on glass and flexible substrates for optical and electric characterisation. It was shown by bending tests that the conductive fabrics retain both flexibility and electrical conductivity. Finally, complete n-i-p single junction a-Si:H cells were fabricated on different types of substrates such as glasses, polyester fabric and polytetrafluoroethylene fabric (PTFE). Several challenging aspects related to the fabrication and characterisation of solar cells on fabrics are highlighted. Cells on woven fabrics were shown to be active photovoltaic devices though with lower response than equivalent cells on rigid glass substrates.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.