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Novel and facile investigation applying polyethylenimine (PEI) functionalised Single-wall Carbon Nanotubes (SWCNTs) for detection of heavy metal ion, copper (Cu2+) ions has been studied as a nanosensing platform. PEI/SWCNTs shows highly selective and rapid detection of Cu2+ ions since SWCNTs having large surface area shows high porosity and high chemical reactivity towards Cu2+ ions with high stability. FESEM and Raman Spectra measurements have been employed for characterising the nanocomposite and these techniques indicate that the PEI functionalised SWCNTs have been favourably synthesised. The detection of Cu2+ ions on the fabricated PEI/SWCNTs nanocomposite has been carried out by UV-vis spectroscopy. This study illustrates that PEI@SWCNTs nanoplatform is highly sensitive for selective and stable sensing of Cu2+ ions in the range of 0.01 µM to 100 µM with lower limit of detection (LOD) of 6.2 nM in aqueous medium. Selectivity and stability studies suggest that it is a unique and versatile platform for detection of copper ions rather in complex mediums with long-term usability. [ABSTRACT FROM AUTHOR]

This work is conducted to improve the electrochemical performance of PANI with the incorporation of spinel‐type transition metal oxide, that is, 1 wt.% of nickel ferrite (NiFe2O4) (NF). The addition of NiFe2O4 into the PANI matrix is accomplished via in situ oxidative polymerization approach at a very low temperature (0‐5°C). It is observed that the various valence states of NiFe2O4 in the electrolytic ions considerably increase due to formation of a well‐interconnected conducting network with PANI. The requisite interaction of PANI/NiFe2O4 is verified by Raman analysis and Fourier Transform Infrared Spectroscopy (FTIR). PANI1:1/NF1 ratio of the composite facilitates strong conducting route improving delocalization of the electrons in the polymeric chain resulting in extra stability of the system. It is observed that NF nanoparticles fills the gaps in the polymeric matrix rendering to attain highest specific capacitance of 758 F g−1 of the PANI 1:1/NF1 electrode cell as compared to bare PANI1:1 (677 F g−1), PANI1:2 (500 F g−1), NF (253 F g−1) and other PANI1:2/NF2 (686 F g−1) samples at 10mV/s. The PANI1:1 device also shows energy density ~ 54 W kg−1 at 0.3 mA/cm2 with corresponding power density at ~1705 W kg−1, and the cyclic stability ~97% after 10,000 GCD cycles. The said device also exhibits a lower charge transfer resistance (Rct) 0.35 Ω as compared to other fabricated devices. NiFe2O4 acts as a 'superhighway' for charge transportation between PANI, which is beneficial for supercapacitors. [ABSTRACT FROM AUTHOR]

This paper presents a two-step enhancement and a comprehensive analysis of single-walled carbon nanotubes (SWCNTs) wrapped polyaniline nanofiber (NPANI) ammonia (NH3) gas sensor at room temperature. SWCNT-PANI composites are successfully synthesized using an efficient and cost-effective rapid in situ chemical polymerization method. The structural morphology and modification of the samples are characterized using field-emission scanning electron microscopy and HRTEM. FTIR and Raman spectroscopic studies are also performed to gain a better insight into the chemical environmental interaction in the as-prepared nanocomposite. The analysis confirms the successful formation of the nanocomposite. The observed NH3 gas-sensing response at 10 ppm of SWCNT, f-SWCNT (functionalised SWCNT), and SWCNT-PANI composite sensors are 5%–6%, 18%–20%, and 24%–25%, respectively. The SWCNT-PANI composite sensors have shown higher repeatability, selectivity, long-term stability, and fast response-recovery characteristics as compared to f-SWCNTs and pristine SWCNT sensors. Concentration and temperature dependent gas-sensing studies are also analyzed. The sensor response also shows a linear relationship with NH3 gas concentration and an inverse relationship with increasing temperature. [ABSTRACT FROM AUTHOR]