Study Of Fabrication And Performance Of Electrically Conducting PANi/Spandex Composite Yarns Used In Smart Textiles

Smart Textiles is increasingly paid attention being regarded as a new technical product. Some experts consider it is extremely promising in the textile/garment industry. As one of the most important materials made into Smart Textiles, electrically conductive fibers have been extensively studied.Since electrically conductive polymers were discovered over twenty years ago, the research in this field has been very active. Some researchers used conductive polymers to fabricate conductive fibers Polyaniline is the most popular polymer because of its simple polymerization, stability as well as its high electrical conductivity.There are mainly two types of fibers made with polyaniline. One type of fibers is directly spun from polyaniline, the other is to coat polyaniline onto fibers which is used as a reinforcing substrate The former has strict requirement about solution and spinning machine, and the fiber is plastic. The latter is the most promising one. Therefore many researchers have been trying to fabricate polyaniline-coated fiber with high electrically conductivity by many means.In-situ polymerization is commonly used technology to produce polyaniline-coated fibers although there are some technical issues to be explored, for example, the poor electrical stability, insufficient understanding about the effect of ambient conditions on the electricalconductivity of fibers. Plasma treatment is a sophisticated technology in modifying the surface of fibers.In this dissertation, PANi/Spandex composite yarns were prepared by carrying on plasma treatment and using in-situ polymerization The effect of processing conditions of plasma treatment on the electrical conductivity of polyaniline coated fiber was studied. The investigation of the effect of ambient conditions on electrical conductivity and investigation of the fiber's response to an environmental stimulus were undertaken as follows.1. The optimal processing parameters of in-situ polymerization were worked out by experiments and statistics.2 The effect of the processing conditions on the electrical conductivity of the fibers was studied.3. The effect of the environment on the electrical stability of the electrically conductive fibers was investigated.4. The relationship between the structure and properties of the polyaniline coated fibers and the fiber's response to an external stimulus were studied.According to the specific experiments and analysis described in this dissertation, the following conclusions have been drawn out:1. Adopting experiments and statistics methods, the optimal processing parameters of in-situ polymerization have been worked out: concentration of oxidant is 0.02 g ml-1, concentration of'doping' agent is 0.5 mol L-1, duration of immersion is lh, duration of processing is 1h2. The three optimal plasma treatment parameters are: processing power is 157w, processing duration is 2.2min, atmospheric pressure is 27Pa.3. Comparing with electrically conductive fibers without plasma treatment, electrically conductive fibers with plasma treatment have higher electrical conductivity and better electrical stability4. The effects of ambient conditions to the electrical conductivity of the polyaniline-coated fibers are: the effect of the humidity on the conductive fibers is not significant, the effect of the temperature on the conductive fibers is significant.5. The response of electrical conductivity of fibers to stretch was significant The change of the conductivity was significant when the composite fiber is stretched, and the relevant curve is obtained. It supports an important evidence to the use of the fibers in Smart Textiles.