Summary Combination of PANI and the cost-effective graphite can obtain composites with good electrochemical performance. For the synthesis method of in-situ polymerization of aniline in presence of GNP, the type and content of oxidant can affect the electrochemical properties of PANI/GNP composites. Besides, the addition of excess dopant can influence the electrochemical properties of a PANI-dominated system. The two eco-friendly reduction ways, namely polymerization of dopamine and adding TA, both produced graphite with good dispersion stability and enhanced interaction with PANI. But the reduction effect of dopamine polymerization was weak, and the non-conductivity of PDA has negative effect on the electrochemical performance of the composites. Using the environmental friendly TA is an effective and facile way to produce cost-effective PANI/graphite composites for supercapacitor purpose. Comparing the two types of graphite, rGO showed lower conductivity and more defects in the carbonaceous structure compared to GNP. In my study, the PANI/(GNP-TA) (1:0.1) composites, which was prepared by using APS as oxidant and without dopant, exhibited the highest capacitive ability. In a three-electrode testing system, the PANI/(GNP-TA) composite showed a high specific capacitance of 351.2 F g-1 at 10 mV s 1. The corresponding two-electrode solid-state supercapacitor device exhibited a promising energy density of 2.3 Wh kg-1 at 0.5 A g-1, which was comparable to the commercially available supercapacitors (around 5 Wh kg-1). But for application the rate capability of the composite needs to be enhanced, in order to maintain the good capacitive performance at high current density.

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As technology advances, a need for non-metal, conductive materials has arisen for several types of applications. Lithographic techniques are helpful to develop some of these applications. Such techniques require materials that are insulating and become conductive after irradiated. Composites of polyaniline in its emeraldine base form (PANI-EB) doped with photo-acid generators (PAG) become conductive upon photo-irradiation. This increase in conductivity is due to the protonation of PANI-EB. Such materials may be utilized to fabricate conducting patterns by photo-irradiation; however, the conductivity obtained by direct irradiation of PANI-EB/PAG composites is normally quite low (<10-3 S/cm) due to aggregation of highly loaded PAG. In this work, poly(ethylene glycol) (PEG), a proton transfer polymer, was added to PANI-EB/PAG. Results showed the addition of low molecular weight (MW) (550) PEG significantly enhanced the photo-induced conductivity to a level comparable to that of PANI-salt synthesized by oxidizing aniline in the presence of an acid. High MW (8000) PEG is less effective than PEG 550, and composites of PANI-EB and N-PEG-PANI showed conductivity as high as 102 S/cm after treatment with HCl vapor. The photo-induced conductivity of the N-PEG-PANI/PANI-EB/PAG composite reached 10-2-10-1 S/cm. Polychlorinated biphenyls (PCBs) are a class of chemicals with 209 different congeners, some of which are known carcinogens, and are persistent organic pollutants in the environment. After its synthesis, it was seen as a phenomenal additive in a multitude of different applications leading to the wide spread use of PCBs and a need for a safe, effective, and inexpensive remediation technique. While it is known that magnesium can degrade PCBs, the mechanism of this reaction was not well-understood. In order for magnesium to be broadly used as a remediation tool, it is necessary to fully understand how the reaction is taking place and if the PCBs are able to be fully dechlorinated into biphenyl. This research focuses on the hydrodechlorination of PCBs with zero-valent magnesium in acidified ethanol. The degradation pathways of 2, 2', 3, 5, 5', 6- hexachlorobiphenyl were investigated to determine the identity of the daughter PCBs produced, how and if they continue to be dechlorinated into biphenyl. The proton source for this hydrodehalogenation reaction was also studied using both deuterated solvent and acid to give more detail to the mechanism of this reaction.

This thesis focuses on the electrical output of polyaniline films subjected to uniaxial strain in hydrochloric acid solutions. Polyaniline belongs to novel class of materials known as conducting polymers. Alternating single and double bonds in the backbone of conducting polymers allow them to transmit electric charge when they are doped with negatively charged ions. Modifying the degree of doping and other electrical/chemical treatments allow conducting polymers to exhibit conducting, semi-conducting, or insulating electrical properties. Resilient mechanical properties, good processability, and low cost make conducting polymers good candidates for applications traditionally held by metals and semi-conductors. When tensile strain is applied to polyaniline in an electrolyte solution, the material selectively absorbs negatively charged ions. This charge imbalance produces a measurable electrical output. Theoretical models based on Fick’s second law of diffusion were compared against experimental results to determine fundamental material properties such as diffusivity and ion solubility in polyaniline. These properties were used to quantify polyaniline as a sensor material based on characteristics including sensitivity, accuracy, precision, range, linearity, and error. Films were cast from solutions of polyaniline powder (Mn = 65,000) in N-methyl-2-pyrrolidinone solvent, with thicknesses ranging from 2.72 to 158 µm.

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