Study On Influence Of Preparation Process On Characters Of PPy Conducting Thin Film Deposited On Porous Substrate

Conducting polypyrrole (PPy) is a kind of conducting polymer which is applied widely. As new conducting material, it has advantages of high conductivity and good thermal stability. Thus, how to get conducting PPy thin film with good characters, has been the study target of many scientists long time ago. But in the application of electron device, it is demanded grealy that prepare conducting PPy thin film on the porous insulating substrate. The paper carries on the study of relative theory and experiment with the target of forming conducting PPy thin film with high conductivity on the porous insulating substrate.Based on theory of surface and interface, the paper analyses microscope structure and state of the surface of porous insulating substrate, and offers a way of modifying the porous substrate surface with self-assembly technology, that is forming self- assembly thin film made by anion surfactant and coupling agent on the substrate. This way can improve the adhesion state of conducting PPy thin film, and get even and compact thin film. In this paper, conductivity and character parameters of aluminium electrolytic capacitor, show the influence of different kinds and concentrations of surfactant on the charactersof the thin film. With the theory of Hydrophile-lipophile Balance (HLB), it is found that the most suitable anion surfactant for preparation of PPy is heptanoic acid, and get a conclusion that there is a best matching relation between the concentration of surfactant and the state of the porous substrate.With the way of two steps polymerization (chemical polymerization and electrochemical polymerization), the problem that electrochemical polymerization can not carry on porous insulating substrate which as anode is resolved. That is forming a layer of PPy thin film with chemical way as anode first, then electrochemical polymerization can carries on it. In the paper, it is studied that the characters of conducting PPy thin film formed in this way on different substrates of ceramic and Al2O3, and with the orthogonal experiments, it is discussed that the influence of different electrochemical polymerization conditions (concentration of monomer and electrolyte, time, current and so on) on the characters of conducting PPy thin film formed on Al2O3 substrate.