Study Of Fabrication And Performance Of Electrically Conducting PANI/Wrapped Spandex Composite Fabics

A type of electrically conducting PANI/ wrapped Spandex composite fabric was fabricated by in situ adsorption polymerization process, which was encasing each single fiber of the textile assembly with a smooth, coherent layer of the electrically conductive polymer. By in situ chemical oxidative polymerization under different conditions, it was found that electrically conductive property of composite fabric was affected by different polymerization conditions, and it would be improved by re-doping process. The computation on the surface conductivity of these anisotropic conductive composite fabrics was conducted under the static and dynamic stressed state respectively by establishing a mathematic model. Since it was awkward to characterize the signal sensibility while the fabric was subjected to stretching using the conventional testing method, an improved method was developed in virtue of some latest technologies. The electrical properties of the conducting fabrics were therebymeasured based on the new testing method.This thesis reported in detail the electrically conducting performances of the conductive fabric with the change of external strain. The experiments showed the stress significantly changed the electrical properties of conductive fabric. The surface resistance in warp direction increased initially and then decreased with the gradual increase of elongation and the surface resistance in weft direction decreased under the same condition. However, when the elongation decreased from its maximum point, the surface resistance in warp direction gradually increased whilst the surface resistance in weft direction gradually decreased. The change in surface resistance with an increase in elongation of fabrics did not totally coincide with the change in surface resistance with a decrease in elongation. Except a little increase in electrical resistance in the first repeated tensile experiments, the resistances nearly kept unchanged after ten times fabric stretching both in warp and weft directions. In addition, the compressing experiments showed the surface resistance decreased remarkably when the compressive loads were added to a certain degree. But the change was little during the initial and final phases.In this thesis, a detailed investigation on the electrical stability of the conductive fabrics was carried out. It was found that the conductivity of the conductive fabric decreased gradually day by day under the room temperature and leveled off after 30-45 days. Meanwhile, the ambient condition greatly affected the conductivity. The conductivity decreased along with an increase of the temperature and a decrease of relative humidity around the same temperature. But the rubbing experiments showed that the rub action would not affect the electrical properties of the conductive fabrics.The smooth surface and the cross-section of these drawing or coated fibers could be seen in the electron scanning microscope (SEM) and optical microscope pictures. The analysis showed that the PANI was deposited on the surface of fabric and formed a smooth and uniform film. The figure of the cross-section was changeable before and after reaction, which became a skin-core structure from an anomalistic concavity structure. Both the mechanical tensile and the washing process would result in breaking off the uniform film. But the conducting performance of the conductive fabric would come back to the original level after a re-doping process.