Conducting polymers, or synthetic metals, have emerged as versatile materials with high electrical conductivity, enhanced environmental stability, diverse structures, and tunable doping mechanisms. In this study, polypyrrole (PPy), both Sodium dodecyl sulfate (SDS)-doped and undoped, was synthesized with a series of PPy nanocomposites containing 5–20 wt% hausmannite (Mn3O4) nanoparticles (NPs) via in situ chemical oxidative polymerization using FeCl3·6H2O as the oxidizing agent and SDS as the dopant. FTIR analyses confirmed strong polymer–nanoparticle interactions, effective doping, and enhanced chain conjugation, particularly in SDS-assisted composites. XRD and DSC revealed an amorphous structure and demonstrated that Mn3O4 incorporation restricted segmental mobility of PPy chains and improved thermal stability. DC electrical conductivity measured by the four-probe method showed that in SDS-assisted composites, conductivity decreased with increasing Mn3O4 due to disruption of the PPy conjugation network, whereas in the undoped series, conductivity increased slightly up to 15 wt% Mn3O4 before declining at higher loadings due to nanoparticle aggregation. SEM analysis revealed that SDS-assisted PPy exhibited a denser morphology, while Mn3O4 NPs were cuboidal with moderate agglomeration. In the SDS-doped composites, uniform embedding of Mn3O4 enhanced compactness and minimized voids, indicating strong synergistic interactions between the polymer and inorganic phases. Cyclic voltammetry (CV) studies demonstrated that SDS-doped composites exhibited higher specific capacitance than the undoped samples, attributed to improved electroactive surface area and ion accessibility. The 5 wt% SDS-doped Mn3O4–PPy composite achieved a specific capacitance of 86.22 F g⁻¹, significantly outperforming the undoped analogue (58.34 F g⁻¹). Electrochemical impedance spectroscopy (EIS) of the 5 wt% SDS-doped Mn₃O₄–PPy electrode further revealed a lower solution resistance (2.47 Ω) than that of the undoped electrode (6.30 Ω), indicating improved electrochemical transport characteristics. In addition, the SDS-doped nanocomposite retained 88.5% of its initial capacitance after 3000 charge–discharge cycles at 2 A g⁻¹, demonstrating good electrochemical stability and long-term cycling durability. These findings highlight the potential of SDS-assisted PPy–Mn₃O₄ nanocomposites as efficient electrode materials for supercapacitor applications.

SDS-doped and undoped polypyrrole–Mn₃O₄ nanocomposites: synthesis, structure, electrical conductivity, and supercapacitor performance

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发表日期：

2026年8月4日

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Eman A. Alabdullkarem,
Siham K. Abdelrahim,
Amra Al Kenany,
Yousef Alqurashi,
Rihab M. Omer,
Moustafa A. Rizk

摘要

Conducting polymers, or synthetic metals, have emerged as versatile materials with high electrical conductivity, enhanced environmental stability, diverse structures, and tunable doping mechanisms. In this study, polypyrrole (PPy), both Sodium dodecyl sulfate (SDS)-doped and undoped, was synthesized with a series of PPy nanocomposites containing 5–20 wt% hausmannite (Mn₃O₄) nanoparticles (NPs) via in situ chemical oxidative polymerization using FeCl₃·6H₂O as the oxidizing agent and SDS as the dopant. FTIR analyses confirmed strong polymer–nanoparticle interactions, effective doping, and enhanced chain conjugation, particularly in SDS-assisted composites. XRD and DSC revealed an amorphous structure and demonstrated that Mn₃O₄ incorporation restricted segmental mobility of PPy chains and improved thermal stability. DC electrical conductivity measured by the four-probe method showed that in SDS-assisted composites, conductivity decreased with increasing Mn₃O₄ due to disruption of the PPy conjugation network, whereas in the undoped series, conductivity increased slightly up to 15 wt% Mn₃O₄ before declining at higher loadings due to nanoparticle aggregation. SEM analysis revealed that SDS-assisted PPy exhibited a denser morphology, while Mn₃O₄ NPs were cuboidal with moderate agglomeration. In the SDS-doped composites, uniform embedding of Mn₃O₄ enhanced compactness and minimized voids, indicating strong synergistic interactions between the polymer and inorganic phases. Cyclic voltammetry (CV) studies demonstrated that SDS-doped composites exhibited higher specific capacitance than the undoped samples, attributed to improved electroactive surface area and ion accessibility. The 5 wt% SDS-doped Mn₃O₄–PPy composite achieved a specific capacitance of 86.22 F g⁻¹, significantly outperforming the undoped analogue (58.34 F g⁻¹). Electrochemical impedance spectroscopy (EIS) of the 5 wt% SDS-doped Mn₃O₄–PPy electrode further revealed a lower solution resistance (2.47 Ω) than that of the undoped electrode (6.30 Ω), indicating improved electrochemical transport characteristics. In addition, the SDS-doped nanocomposite retained 88.5% of its initial capacitance after 3000 charge–discharge cycles at 2 A g⁻¹, demonstrating good electrochemical stability and long-term cycling durability. These findings highlight the potential of SDS-assisted PPy–Mn₃O₄ nanocomposites as efficient electrode materials for supercapacitor applications.

SDS-doped and undoped polypyrrole–Mn3O4 nanocomposites: synthesis, structure, electrical conductivity, and supercapacitor performance

摘要

SDS-doped and undoped polypyrrole–Mn₃O₄ nanocomposites: synthesis, structure, electrical conductivity, and supercapacitor performance