| Polyaniline (PANI) nanotubes not only shows excellent conductivity, resulting from its base polymer, but also is endowed with more orderly arrangement of the macromolecular chains, larger specific area, unique hollow structure, and so on. It is well-known that the macroscopical properties of such polymer have a great relationship with its microcosmic morphology. So the investigations on the preparation methods, formation mechanisms and functional applications of low-dimensional structures of PANI have attracted considerable attention from the materials research community. In this dissertation, unique low-dimensional structures of PANI were synthesized and in situ doped with chiral acid (1S)-(+)-10-camphorsulfonic (CSA) through chemical oxidation polymerization, including nanotubes, nanofibers and nanoparticles. The as-prepared PANI nanostructures were characterized in terms of their morphologies, structures and properties such as electromagnetism. Furthermore, a mechanism based on two-tier plane micelle model was proposed for the first time to elucidate the formation process of the rectangular nanotubes of PANI. The main work and conclusions were listed as followings.Firstly, doped with CSA, PANI nanotubes were synthesized via the method of in situ soft-template polymerization. PANI nanotubes with different types, in and outer diameters and wall thickness, as well as other PANI low-dimensional nanostructures, were obtained by adjusting reaction conditions such as concentration of ANi and CSA, and molar ratio of ANi to CSA. The results showed that the optimum conditions for the synthesis of PANI nanotubes were as follows:3/4≤nCSA/nANi≤1,0.005M≤[ANi]≤0.1M, nAPS/nANi=1.1; the reaction temperature was in the range of 0-5℃; the reaction time was 16h. The outer diameter and wall thickness of the as-prepared nanotubes were found to be 200-500nm and 30-150nm, respectively. It was also concluded that the obtained PANI nanotubes were composed of more orderly arranged molecular chains of chiral nature, induced by CSA, and crystallization occurred during the formation of such nanostructure.Secondly, the electromagnetic and thermal properties were characterized for the as-prepared PANI with low-dimensional nanostructures. The electrical test showed that the conductivity of chiral PANI nanotubes was conspicuously higher than that of nanofibers and nanograins, and abruptly increased with the improvement of effective doping degree as well as orderly arrangement of their molecular chains. The study on electromagnetism revealed that the chiral PANI exhibited diamagnetism under 300K, and its unchiral counterpart changed from diamagnetism to paramagnetism with the transformation of magnetic field strength. What is more, the results on thermal properties showed that such performance could be improved with the enhancing of doping degree and orderly molecular arrangement within a certain range.Thirdly, according to the results of morphological observation and spectral analysis, a new mechanism on the formation of rectangular nanotubes was proposed, which was on the basis of Two-tier plane micelles. The products during the reaction process were investigated in terms of their pH values, molecular structures and morphologies. The results indicated that the polymerization of such rectangular nanotubes should be divided into the following three stages:the micelles shaped, the emerging of heterogeneous structures of oligomers, and the formation of the final nanotubes with rectangular cross sections.Finally, low-dimensional nanostructured PANI was successfully achieved on a 100-time pilot-plant through the coordinate controlling heat transfer and mass transfer technique. Also, the comparative researches on electromagnetic loss and absorbing properties were conducted for the as-prepared PANI nanosructures with different chiral or morphological characteristics. The results showed that both the dielectric loss and magnetic loss of nanotubes and nanofibers were apparently higher than that of nanograins. The chiral PANI showed both dielectric loss and magnetic loss, and its unchiral counterpart only had dielectric loss. Whether or not the PANI structures belong to the chiral nature, as well as their morphologies, were found to be the key factors to affect such electromagnetic loss and absorbing properties.
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