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

Smart Textiles is increasingly regarded as a new and high technical product. Some experts consider it is an extremely promising trend of the textile/garment industry.As one of the most important materials made into Smart Textiles, conductive fiber is extensively studied. There are several types of commercial available conductive fibers, such as metal coated fibers, carbon filled or copper sulfide filled fibers etc. However, these fibers all have shortages and limited practical uses.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 commonly used polymer because of its simple polymerization, stability in air and water as well as its high electrical conductivity.There are mainly two types of fibers made with polyaniline. One type of fiber 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. So many researchers have been trying to fabricate polyaniline-coated fiber with high 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 conducting mechanism of polyaniline-coated fiber, insufficient understanding about the effect of the processing conditions and the structure of the polymer on the electrical conductivity of fibers.In this dissertation, some basic researches and explorations about the effect of the processing conditions on the electrical conductivity of polyaniline coated fiber, and investigation of the fiber's response to anenvironmental stimulus were undertaken as follows:1. Selecting the materials used in experiments.2. Studying the effect of the processing conditions on the electrical conductivity of the fibers.3. Adopting the universal rotary experimental design method to design the experiments, optimizing the parameters by establishing multi-objective mathematical pattern and using the method of random searching.4. Studying the relationship between the structure and properties of the polyaniline coated fiber.5. Investigating the fiber's response to an environmental stimulus.According to the specific experiments and analysis described in this dissertation, the following conclusions can be made:1. The process to produce electrically conducting fibers using Spandex as a substrate is:Preparation#Dry#Dip in aniline#Polymerization#Rinse#Dry2. The concentrations of oxidant, "doping" agent and aniline have significant influence on the electrical conductivity, but the polymerizing temperature and time affect the result little in a wide range.3. The three optimal processing parameters to produce electrically conducting fibers are: concentration of oxidant is 0.01dg-ml-1, concentration of "doping" agent is 2.5mol-L-1, concentration of aniline is 0.23mol-L-1.4. The conductive composite fiber has smooth surface, high conductivity, good mechanical properties and high stability in air and water.5. The response of electrical conductivity of fibers to stretch was significant.