Dissertation > Excellent graduate degree dissertation topics show

Relationship between Electric Properties Variation of Polyaniline Film in Reduction Process and Its Gas-sensing Characteristic

Author: XuKe
Tutor: TangHeQing；ZhuLiHua
School: Huazhong University of Science and Technology
Course: Materials Physics and Chemistry
Keywords: Polyaniline Double potential step Electrochemical Reduction Cyclic voltammetry Doping acid Lose percolation theory Ammonia sensor
CLC: TB383.2
Type: PhD thesis
Year: 2007
Downloads: 257
Quote: 1
Read: Download Dissertation

Abstract


Changes in electrical properties research polyaniline film redox process is conjugated conductive polymer material is a basic subject. However, due to the complexity of this process, although scholars proposed many theoretical models attempt to satisfactorily explain this phenomenon, although some qualitative conclusions drawn, it has failed to carry out quantitative description. In this thesis, using changes in the electrical properties of the improved two-step technique polyaniline film during the restore process. The study found that the extension of the main membrane capacitance and resistance with reduction time and / or reduction potential negative shift and change, and the acromion restore stage chronoamperometry curve, which indicates that the polyaniline film as a two-stage reduction process. Absorption lose seepage heterogeneous model proposes an improved theoretical model based on electrochemical excitation configuration the relaxation theory model advantages and use of the theoretical model to explain these experimental results satisfactory. This new model to overcome the possible difficulties of these two models, not only can quantitatively explain the changes in the electrical properties of polyaniline film during the restore process can produce reasonable description of the two-phase separation of the membrane in the reduction process of the polyaniline film development and its impact on membrane electrical properties. Take advantage of the improved two-step method of acetonitrile Film Resistors the polyaniline restore process and injected into the membrane to restore the relationship between the power, and to explore the impact of different dopants in the process. Membrane resistance and restore the power relationship between the performance of the S-type curve. The obtained polymer electro-reduction process critical restore electricity Q_c of, Q_c physical meaning to form a continuous reduction phase the minimum required to restore electricity consumption polyaniline film based on the mathematical model the heterogeneous model proposed in this paper, can . The experimental results show that the doping anions on Q_c value of the size has a great influence, dodecylbenzene sulfonic acid doped polyaniline film relatively with perchloric acid doped polyaniline film having a smaller Q_c; the membrane inject restore power greater than Q_c conductive polyaniline film resistor will increase significantly. In, Q_c The smaller the polyaniline film is more sensitive to restore (off or hybrid), which indicates that more sensitive dodecylbenzene sulfonic acid doped polyaniline film of alkaline or reducing gas. Using the concept of the sensor, we confirmed dodecylbenzene sulfonic acid doped polyaniline film sensor relative perchloric acid doped polyaniline film higher response to low concentrations of ammonia. Finally, we have adopted a potentiodynamic scan to adjust the polyaniline chain structure, and a unique cyclic voltammetry behavior observed in acetonitrile. When the potential scan within a narrow potential window (corresponding to the acetonitrile solution of the polyaniline in the fully reduced state with the intermediate oxidation state between the first pair of conversion oxidation reduction peak), in the cyclic voltammogram, said polyaniline anodic peak split completely reduced state into an intermediate oxidation state. When the lower limit of the potential window is moved to the more negative potentials, polyaniline cyclic voltammogram of a significant change in its electrical properties are also changed in the process. This novel behavior and depth reduction, as well as the dedoping process the polyaniline chain structure changes. Further study found When the polyaniline film is oxidized within the potential window of the lower limit (less than-0.8V) having a lower potential to restore the period of time after treatment, the polymer film is a significant increase in the response capability of the ammonia and the air sensitive response less affected by humidity. Reducing treatment by the depth of the polyaniline film and successfully prepared ammonia sensitive concepts sensor.

Related Dissertations

  1. The Preparation of Polyaniline-Metal Complex and the Study on Its Catalytical Property,O634
  2. Preparation and Anticorrosion Properties of Doped Polyaniline/Epoxy Coating,TQ637
  3. Electrochemical Studies on Interaction between ApoCopC、BSA and Cu(Ⅱ)、Cu(Ⅰ)、Cd(Ⅱ)、Ag(Ⅰ),O646
  4. The Fabrication and Application of the Preanodized Inlaying Ultrathin Carbon Paste Film Electrode,O657.1
  5. Polyaniline / short fiber reinforced natural rubber properties,TQ330.1
  6. Nano Pt / SiC Preparation, Characterization and Electrochemical Catalytic Performance,TM911.4
  7. Synthesis and Characterization of Polyaniline Micro/nano Structure and Its Composites,TB383.1
  8. Carbon nanotubes doped polyaniline and its application in gas sensors,TB383.1
  9. Electrochemical Treatment of pesticide intermediates ( phthalonitrile ) Wastewater,X786
  10. The Preparation and Characterization of Conducting Polymers with Electromagnetic Function,TB383.1
  11. Organic acids control the synthesis of polyaniline satisfied / micron-sized structures,TB383.1
  12. One-dimensional Core-shell Structured Multi-walled Carbon Nanotubes/Polyaniline Nanocomposites,TB383.1
  13. Syntheses and Properties of Calix "4" Arene Derivatives with Ferrocene Groups,O627.81
  14. Study on the Fibre Modified by Polyaniline and the Electrical Conductivity of That,TQ340.1
  15. Synthesis and Properties of Conducting Polyaniline-based Radar Absorbing Composites,TB34
  16. Organic/Inorganic Conductive Nanocomposites Fabrication, Characterization and Application,TB383.1
  17. Permeation of Sodium Chloride Through Polyaniline-epoxy Composite Membrane,TB383.2
  18. Synthesis and Properties of Nano-Silver/PANI Composite Materials,TB333
  19. Studies on the Electrochemical Properties of PANI/REmOn （RE=La, Ce） Nanocomposites and the Catalysis of Pt Electrode Modified by Them to the Oxidization of CH3OH and HCOOH,TB33
  20. Research on Synthesis and Luminescent Properties of Polythiophenes with Dioxane Group,O631.3
  21. Synthesis and Characteristics of Poly (Sodium 4-styrensulfonate)-grafted Grapheme and Its Nanocomposite with Polyaniline,O631.3

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