Sysnthesis And Characterization Of PPy With Different Morphologies

Polypyrrole (PPy) has gradually been developed into a hot research direction in the field of conductive polymer with its advantages of easy synthesis, high conductivity, environmental stability, non-toxic and so on. For the conductive polymer materials, it is no doubt that the electrical conductivity is the main technical indicators of the performance. Many practical application of conductive polymer materials is often directly depends on its advantages and disadvantages of conductive ability, therefore it is necessary to carry out the controllable study of the conductivity of conductive polymer. It has been proved as many researches in both home and abroad that the morphology of PPy has a direct effect to the conductivity of conductive polymer. In view of this, this paper will mainly study the synthesis, characterization and conductivity of a series of PPy with particle, linear, and from the particles to film morphology.In this paper, polypyrrole was first synthesized by a chemical oxidation polymerization method as pyrrole, FeCl3and the mixture of acetonitrile and water were used as the monomer, oxidant and solvent, respectively. Then, a series of polypyrrole with particle morphology (marked as E-PPy) were synthesized by changing the volume ratio of ethyl alcohol to water (note as VREW) in the range of0:10to7:3. The results showed that VREW had direct effect to the conjugated degree of PPy molecule. Further study indicated that the average particle size of PPy decreased with the increase of VREW in the range of0:10to7:3. However, still with the increase of VREW in the range of0:10to7:3, the yield and conductivity of PPy showed a trend of first increase and then decrease. Moreover, the yield and conductivity reached their maximum value both at the VREW value of2:8.Furthermore, a series of polypyrrole with a gradual change from particle to film morphology (marked as A-PPy) was synthesized by ammonium persulfate (APS) as oxidant and the mixture of acetonitrile and water as solvent also by the chemical oxidation polymerization method. The results indicated that that particle morphology of PPy turned to the both exist of particle and film-shaped, until the completely film-shaped PPy is obtained with the increase of the volume ratio of acetonitrile to water (note as VRAW) in the range of0:10to7:3. What’s more, still with the increase of VRAW in the range of0:10to7:3, the yield and conductivity of PPy showed a trend of first increase and then decrease, and the yield and conductivity reached their maximum value both at the VRAW value of1:9.Finally, On the basis of the above research, a series of polypyrrole with linear morphology (marked as C-PPy) was obtained by using ammonium persulfate (APS) as oxidant, water as solvent and cetyl trimethyl ammonium bromide (CTAB) as surfactantalso still by the chemical oxidation polymerization method. The results showed that, in the condition that the mole ratio of CTAB to Py was in the range of1:2to1:10, the chang of the dosage of CTAB had no effect to the conjugated degree of PPy molecule, but had a direct effect on the morphology of C-PPy products. With the mole ratio of CTAB to Py was varied from1:2to1:10, the morphology showed a variation law of the irregular linear morphology to neat linear to film formed with particle and linear, and corresponding to the product, the electrical conductivity was1.21S/cm、2.87S/cm and1.54S/cm, respectively. Through raising the reaction temperature of the above product with neat linear morphology (marked as C2) from0℃to25℃, a uniform dispersion particle morphology PPy was obtained, and the conductivity was diminished to1.11S/cm. And through changing the solvent of synthetic reaction system of C2from water to the VREM was2:8and VRAM was1:9as mixed solvent, both exist of particle and linear PPy were obtained, and both of the conducitivity were diminished to0.24S/cm and0.38S/cm, respectively.Pass the textual research work, three kinds of different morphologies PPy products were obtained which with particle、a gradual change from particle to film and neat linear structure named E-PPy、A-PPy and C-PPy, respectively, and was confirmed that the conductivity changed by the morphology changes of PPy products.