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Hexanoic acid (HA) doped polyaniline (PAni) nanocomposites which consist of different contents of untreated double wall carbon nanotubes (u‐DWNT) and carboxyl treated DWNT (c‐DWNT) with titanium dioxide nanoparticles were successfully prepared using template‐free method. Fourier transform infrared, ultraviolet‐visible and X‐ray diffractometer spectra clearly confirmed the chemical structure of PAni nanocomposites. Thermal stability, morphology, conductivity, magnetic properties and reflection loss of PAni nanocomposites were characterized by thermogravimetric analyzer, field emission scanning electron microscope, four‐point probe, vibrating sample magnetometer and microwave vector network analyzer, respectively. From this study, it is shown that electrical conductivity of PAni nanocomposites with u‐DWNT possessed higher conductivity (1.23 × 10–1 to 1.31 × 100 S/cm) compared to c‐DWNT (3.43 × 10–2 to 4.48 × 10–1S/cm). PAni/HA/TiO2/DWNT nanocomposites with 20% of c‐DWNT have been covered by PAni layers to form the highest amount of nanorods/nanotubes. Hence, it shows high heterogeneity that will enhance the dielectric permittivity and contribute to a more disordered motion of charge carriers along the PAni backbone. Therefore, it will eventually contribute to good microwave absorption and potentially apply as an efficient electromagnetic interference shielding material in cell phones. POLYM. COMPOS., 39:1283–1291, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Hexanoic acid (HA) doped PAni nanocomposites which containing aniline (Ani) as monomer was synthesized via template free method. Dielectric (titanium dioxide, TiO2) and magnetic (different dimension of multiwall carbon nanotubes (MWNT)) materials have been added to improve the dielectric and magnetic behavior of the PAni nanocomposites. Fourier transform infrared (FTIR) spectrometer, ultraviolet-visible (UV-Vis) spectrometer and X-ray diffractometer (XRD) analysis confirmed the chemical structure of doped-PAni. Morphology study and thermal behavior of the PAni nanocomposites have been investigated by field emission scanning electron microscope (FESEM) and thermal gravimetric analyzer (TGA), respectively. PAni nanocomposites with longer length and bigger diameter of MWNT possess the highest conductivity (1.51 × 10-2 S/cm) compared with those shorter length and smaller diameter PAni nanocomposites. Microwave absorption study was investigated by microwave vector network analyzer (MVNA) from 0.5 to 18 GHz. Among all the PAni nanocomposites, PAni nanocomposites with MWNT (φ = 10-20 nm, l = 5-15 μm) possess a sharp and narrow peak with high absorption (RL = -58 dB) at 7 GHz. In this study, it is observed that PAni nanocomposites with longer length and smaller diameter exhibit the largest amount of entangled nanorods/nanotubes that will eventually enhance the heterogeneity of the nanocomposites. Thus, it significantly induces the space charge polarization along the PAni backbone and indicates the strongest microwave absorption. [ABSTRACT FROM AUTHOR]

In this work, Polyaniline/titanium dioxide (PAni/TiO2) nanocomposites without and with addition of fullerene such as pristine fullerene (C60) and small gap fullerene (S.G.F) were prepared through template‐free method by using hexanoic acid (HA) as a dopant. FTIR and UV‐Vis spectra confirmed the chemical structure of conjugated PAni and indicated that the resulted PAni is in conducting state. The existence of fillers in PAni nanocomposites were confirmed by the characteristic peaks of TiO2 and fullerene in XRD pattern. Based on FESEM images obtained, nanocomposites formulated with C60 (PAni/HA/TiO2/C60) formed the nanorods/nanotubes and microrods/microtubes with the biggest diameter (240 nm), followed by PAni with S.G.F (PAni/HA/TiO2/S.G.F) and PAni without the addition of fullerene (PAni/HA/TiO2) with diameter of 180 nm and 160 nm, respectively. Besides, PAni/HA/TiO2/C60 also possessed the highest electrical conductivity of 1.708 × 10−1 S/cm as compared to PAni/HA/TiO2/S.G.F and PAni/HA/TiO2 (4.531 × 10−3 S/cm to 1.439 × 10−2 S/cm). Microwave absorption studies of PAni nanocomposites were carried out by using Microwave Vector Network Analyzer (MVNA) in the frequency range of 0.5–18.0 GHz. Among all nanocomposites, PAni/HA/TiO2/C60 exhibited a narrow and the highest reflection loss (RL) peak of −61.3 dB at 9 GHz due to the highest conductivity (1.708 × 10−1 S/cm), dielectric permittivity (0.46) and heterogeneity of PAni (larger amount of nanorods/nanotubes and microrods/microtubes) that have induced more disordered motion of charge carrier along the backbone of PAni. Thus, it eventually enhanced the molecular polarization such as greater space charge relaxation and hopping of confined charges. [ABSTRACT FROM AUTHOR]