Influence of the dopant on the polypyrrole moisture content: Effects on conductivity and thermal stability

Abstract

Having in mind to produce electrically conductive carbon-epoxy composite materials, we have filled an insulating epoxy resin with an electronic conducting polymer, polypyrrole (PPy). To select the PPy that best suits this process, various PPys were chemically synthesized. The syntheses were performed in water via a dispersion polymerization route using, initially, either FeCl 3 (PPy-Cl Ϫ ) or (NH 4 ) 2 S 2 O 8 (PPy-HSO 4Ϫ ) as oxidizing agents. Then, using (NH 4 ) 2 S 2 O 8 as the oxidant, two other PPy doped with aromatic species were obtained due to the dissolution of paratoluenesulfonic acid (PPy-TS Ϫ ) or naphtalenesulfonic acid (PPy-NS Ϫ ) in the reaction media. The characterization of the PPy samples by conductivity measurements, together with elemental and thermal analysis, showed that PPy-TS Ϫ exhibits the highest conductivity and thermal stability, with the conductivity remaining steady over 14 days. In addition, a stabilizing effect of the aromatic anions was observed. The experiments have shown that moisture in the PPy cannot be entirely removed and that, with increasing moisture content, the conductivity also increases, indicating an ionic conductivity superimposed on the electronic conductivity usually observed in PPy.

Synthesis and factor affecting on the conductivity of polypyrrole: a short review

“…According to Sasso et al, 43 the decomposition of oxidant tends to produce ions that could act as dopant during chemical PPy polymerization. For instance, when oxidants such as FeCl 3 and APS are used in the synthesis, they form chloride (Cl − and ClO 4 − ) and sulfate (SO 4 − ) ions 43,131,132 …”

Chemical synthesis, characterization, and properties of conducting copolymers of imidazole and carbazole

“…New aromatic nitrogenenous polymers are continuously emerging due to their versatility, easy preparation, and very attractive property-cost performance including much higher gas separation ability than any other polymer. 1 The most widely studied conducting polymers are poly(aniline), [2][3][4][5][6][7][8][9][10][11][12] poly(pyrrole), [13][14][15][16][17][18][19][20] poly(thiophenes), [21][22][23][24][25][26] and poly(carbazole). [27][28][29][30][31][32][33] The carbazole (CZ) homopolymers have potential applications in the field of optoelectronics because of their interesting blue luminescence due to their limited p-conjugation.…”

Thermal Conductivity of Protein-Based Materials: A Review

“…Besides, it is also believed that the chemical process can help improve the interfacial bonding between the graphite nanoplatelets (GNPs) and polymer matrix, which also increased the κ values of the nanocomposites [96]. As reported by C. Cassignol et al, the κ values of polypyrrole (PPy) increased with the moisture content, especially from 8.5% to 13.5% [98]. Tomko et al reported that the hydrated tandem-repeat (TR) protein films had an increased thermal conductivity compared to ambient state TR protein films [13].…”

“…Tomko et al reported that the hydrated tandem-repeat (TR) protein films had an increased thermal conductivity compared to ambient state TR protein films [13]. Therefore, in addition to parameters such as crystallinity, chain orientation and fillers, the κ values of polymers also vary with the change of temperature, moisture and other factors [57,98,99]. Due to the anisotropic structure and microstructure of polymers, the κ values of polymer in the cross-plane direction or the in-plane direction can also be different [100,101,102,103,104].…”