Variation of Ammonium Persulfate Concentration Determines Particle Morphology and Electrical Conductivity in HCl Doped Polyaniline

Abstract

Polyaniline (PANI) is one of conducting polymers which is widely used in various applications especially energy field, like solar cells and batteries. PANI emeraldine salt (PANI ES) is the only type of conducting PANI which can be easily synthesized using a direct mixing method in an oxidizing solution. Ammonium persulfate (APS) is one example of a strong oxidizing agent which is often used in PANI synthesis. The APS concentrations used in this study ranged from 0.1 to 1 M. Infrared and Raman spectroscopy shows that the addition of APS concentrations above 0.5 M produces the non-conducting fully oxidized PANI and phenazine species. Scanning electron microscope (SEM) showed morphological changes of PANI ES from nanofiber (diameter 80 - 110 nm) to granules (diameter 20 - 70 nm) as APS concentration increases. Based on Electrochemical impedance spectroscopy (EIS), conductivity of PANI increases as APS concentration increases with maximum conductivity of 0.36 S cm−1 at 0.5 M.

Polymerization of polyaniline under various concentrations of ammonium peroxydisulfate and hydrochloric acid by ultrasonic irradiation

“…As shown in Table 1, with the increase in concentration of HCl, the E.C of the synthesized PANI also increases. The E.C value of 0.5 S/cm for 2 M HCl was found to be much higher than those reported by Qiu et al 32 (0.162 S/cm) who synthesized PANI by the assistance of microwave, and that of Reza et al 31 (0.36 S/cm) who applied direct mixing method. This confirms the advantage of ultrasonic irradiation over other techniques.…”

“…In second category, when the molar ratio of [APS]/[ANI] ≥ 1.15, the E.C decreases due to over oxidation of ANI 30 . Furthermore, according to Reza et al, 31 when the concentration of APS was above 0.5 M, phenazine will be produced, which could trap electron and thus reduces the E.C.…”

Surfactant doped polyaniline coatings for functionalized gas diffusion layers in low temperature fuel cells

“…According to Reza et al, this peak indicates the presence of phenazine which is often considered as a defect in PANI since it is non-conducting. 57 Further, Reza et al reported a correlation between high APS concentrations and the formation of phenazine, 57 hence in E-pTSA-1 this peak is not visible. In Fig.…”

“…5). Furthermore, the peaks of E-pTSA-1 are shifted to higher wavenumbers which could be due to a higher pH value during electropolymerization 60 and the content of the reduced benzenoid units is higher in A-pTSA-1 Stretching of CQC in benzenoid rings 57 Significant increase indicated presence of phenazine which reduces the conductivity 57 1245 C-N + (bipolaron) stretching vibration, indicates conductivity 19,21 -1135 CQNH + -C (protonated imine group), indicates higher conductivity 19,56,57 Become wider in presence of SDBS 19 1010 -SQO stretching 58,59 Fig. 5 IR spectra of A-pTSA-1 (powder), A-pTSA-1 (coating) and E-pTSA-1 (coating).…”

Liquefied petroleum gas sensing activity of betel nut fiber‐polyaniline conducting composites synthesized by time‐controlled in situ polymerization

“…Which may reduce the PANI (ES) chain length, those chains interact each other forming small particles that agglomerates resulting granules. 68 The effect of polymerization time on electrical conductivity was studied with a fixed molar concentration of HCl (0.1 M), APS (0.01 M) and varied concentrations of aniline in the range of 0.01, 0.03, 0.05, 0.07, 0.09, and 0.1 M. The color changeover of the reaction medium followed the order pink ! purple !…”