Dissertation > Excellent graduate degree dissertation topics show

Preparation and Electromagnetic Properties of Micro/Nanostructured Polyaniline and Its Nanocomposites

Author: SunJun
Tutor: BiHong
School: Anhui University
Course: Polymer Chemistry and Physics
Keywords: polyaniline micro/nanostructure composites electrochemicalproperties
CLC: TB383
Type: PhD thesis
Year: 2012
Downloads: 383
Quote: 0
Read: Download Dissertation

Abstract

Polyaniline (PANI) has attracted considerable attention due to its special doping mechanism, high environmental stability, facile synthesis, low cost, relatively high conductivity and excellent physical and chemical properties. PANI has been explored for widely potential applications in electronic devices, sensors, energy storage, and electromagnetic shielding etc. Micro/nanostructured PANI materials have drawn increasing attractions in the fields of science and application technology, and been a new hotspot of material researches, because they possess the excellences of both conducting polymers and nanomaterials. Therefore, controllable design and synthesis of micro/nanostructured PANI materials and its composites have received great attention. The research of this dissertation is focused on the issues about preparation of micro/nanostructured PANI materials and its composites. The structures, properties and formation mechanism of micro/nanostructured PANI materials are also investigated. The main contents are as follows:1, Large-scale superhydrophobic flower-like micro/nanostructured PANI architectures were fabricated by using valine as the dopant in polymerization. This method has been successfully applied to other amino acids such as threonine, proline and arginine. Particularly, the PANI architectures and thus surface hydrophobic properties can be tuned not only by changing concentrations and sorts of the doped amino acid but also by varying polymerization time. It is expected that this facile and large-scale synthesis may improve potential applications of superhydrophobic PANI films in the fields of biosensors, controllable separation, antifouling and antistatic coatings.2, Net-like PANI architectures were polymerized by using CSA as a dopant with different concentration. The morphologies of the PANI architectures can be tuned by changing concentrations of CSA. It is found that the branch-like PANI chains of the net-like PANI architectures were induced by phenazine-units within its backbone after polymerization under low CAS concentrations. The results indicated that the branch-like chains disintegrate into small linear fragments during galvanostatic charge-discharge cyclings, with a concomitant increase of conductivity and decrease of the internal resistance (IR), which is consistent with a stronger π-π molecule conjugation inside the small linear PANI fragments. Therefore, the branch-like PANI exhibits a relatively higher capacitance property. This work provides a new pathway to design and prepare high-quality PANI-based supercacitors with novel molecular chain structures.3, The PANI/GO nanocomposites with GO sheets covering on the surface of PANI nanoparticles have been successfully prepared by Pickering emulsion polymerization. The main combinding mode of the PANI/GO nanocomposites includes hydrogen bonding and π-π interaction between PANI and GO. The PANI/GO nanocomposites exhibited the higher specific capacitance and better cycling stability than that of pure PANI for their novel structures. It is proposed that the feeding ratio of GO sheets and the synergy between individual components have a pronounced effect on the electrochemical performance of the PANI/GO nanocomposites.4, Hydroxyl-groups-enriched carbon spheres have been synthesized by a glucose hydro thermal method. After in-situ polymerization, a binary cactus-like CS/PANI microsphere composite was obtained. Finally, r-GO was introduced into binary CS/PANI composite by ultrasonication dispersion method to prepare r-GO/carbon sphere/PANI trinary composite. The influence of r-GO mass on specific capacitance of trinary composite has been systematically investigated. It is found that the specific capacitance can be significantly improved after adding a small amount of r-GO. Impedance data indicate that the adding conducting r-GO sheets allow for efficient charge and ions transport, so reduce the internal resistance and improve the electrochemical performance. This work provides a facile pathway to improve electrochemical performance of the electrode materials.5, Hollow poly(o-toluidine)(POT) microsphere can be obtained by the droplet template method through a one-step solution route. The influence of different synthetic conditions on the morphology of POT has been systematically investigated. The hollow POT/Fe3O4composite have been prepared through chemical coprecipitation process by using hollow POT microspheres as template. By changing the concentration of iron salts, the size of Fe3O4nanoparticles that can be tuned ranges from4to12nm. The hollow POT/Fe3O4composite exhibited superparamagnetism and redispersion in aqueous solution. Furthermore, POT/Fe3O4@Au catalysts have been fabricated by in situ formation of gold nanoparticles on POT surfaces through redox activity of POT towards gold ions. Catalytic results indicated this POT/Fe3O4@Au catalysts not only have remarkably high catalytic activity, but also can be reused several times without significant loss in catalytic activity. Notably, the recyclable used of this POT/Fe3O4@Au catalysts can be achieved easy by adding a magnetic field for its superparamagnetism. This will provide insights to research and synthesis of POT based materials for potential applications as efficient and recyclable catalyst vehicle.

Related Dissertations

CLC: > Industrial Technology > General industrial technology > Materials science and engineering > Special structural materials
© 2012 www.DissertationTopic.Net Mobile