A novel orchid-like polyaniline superstructure by solvent–thermal method

Yang, Mei; Xiang, Zhaojun; Wang, Ge

doi:10.1016/j.jcis.2011.08.086

Cited by 17 publications

(17 citation statements)

References 32 publications

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“…13a, PAni in the absence of any moisture shows a sharp peak at 349 nm in its spectrum, which corresponds to the π -π * transition of the benzenoid rings. The small peak at 408 nm can be assigned to the polaronπ * transition, 44 and the broad peak at 659 nm is attributed to the polaron-polaron transition. 45 In Fig.…”

Section: Sensing Mechanisms Studiesmentioning

confidence: 99%

A Comparative Study on Humidity Sensing Performances of Polyaniline and Polypyrrole Nanostructures

2014

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This paper addresses the preparation of polyaniline (PAni) and polypyrrole (PPy) nanostructures as humidity sensor elements. The semicrystalline microstructure and chemical structure of synthesized PAni and PPy were studied by X-ray diffraction and Fourier transform infrared spectroscopy, respectively. The morphology of these polymers was studied by scanning electron microscopy and transmission electron microscopy, indicating fibrillar and tubular nanostructures for PAni and PPy, respectively. The humidity sensing performances of sensors based on the prepared nanostructural PAni and PPy were investigated, and the sensing mechanisms of both systems have been discussed. The interesting reverse behaviors during humidity exposure of PAni-and PPy-based sensors in different water vapor concentrations have been comprehensively justified. The temperature dependency of the electrical conductivity for PAni and PPy samples was investigated. The UV-vis spectroscopy was used to study the effect of moisture on the electronic transport properties of PAni and PPy nanostructures. C Experimental MATERIALSThe aniline and pyrrole monomers, hydrochloric acid (HCl), ethanol, ammonium persulphate (APS, (NH 4 ) 2 S 2 O 8 ), and anhydrous iron (III) chloride (FeCl 3 ) were all purchased

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Section: Sensing Mechanisms Studiesmentioning

confidence: 99%

A Comparative Study on Humidity Sensing Performances of Polyaniline and Polypyrrole Nanostructures

2014

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“…Because of the hydrogen bonding and π-π stacking leading to the more short-range orders in the flower-shaped S-PANI, the peak at 2θ = 6.4 of the flower-shaped S-PANI was higher than that of the leaf-shaped S-PANI. 51 The conductivities of N-PANI and S-PANI were measured by using a four-point probe detector, which is described in Table 1. The conductivity of N-PANI was obviously improved by at least nine orders of magnitude (<10 −9 -10 0 S/cm) as the ES-PANI nanolayer was further grown on both surfaces of the N-PANI.…”

Section: Resultsmentioning

confidence: 99%

Preparation of 2D leaf‐shaped and 3D flower‐shaped sandwich‐like polyaniline nanocomposites and application on anticorrosion

Kang

Wang

Chen

2020

J of Applied Polymer Sci

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The synthesis of triple-layer-structured polyaniline (PANI) conductive nanocomposites, including two-dimensional leaf-shaped and three-dimensional flower-shaped types (S-PANI), via a two-step method is proposed in this study. According to scanning electron microscopic measurement, the triplelayer-structured S-PANI consists of a middle layer of nonconductive PANI (N-PANI) at 100 nm thickness and emeraldine-salt-form PANI (ES-PANI) nanolayer at 40-50 nm thickness. The results of Fourier-transform infrared spectroscopy, UV/Vis spectroscopy, and X-ray diffraction pattern demonstrate that the phenazine unit existed within the N-PANI main chain, leading to the poor conductivity of N-PANI. However, the conductivity of the N-PANI can be extremely enhanced by at least nine orders of magnitudes (<10 −9-10 0 S/cm) when a conductive ES-PANI nanolayer is further grown on the N-PANI outer surface. Finally, the results of oxygen transmission test and electrochemical impedance spectroscopy reveal that the leaf-shaped S-PANI, as an additive in epoxy resin, has the best oxygen barrier property (oxygen transmission rate = 5.86 cm 3 m −2 day −1) and highest coating resistance (5.53 × 10 10 Ω) after 60-day immersion in 0.1 M HCl solution, indicating that the leaf-shaped S-PANI is an excellent anticorrosion additive.

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“…A much higher acidity, which is needed for the formation of polyaniline (pH<2.5), has not been reached. This is an important fact to realize; some researchers regard the aniline oxidation products to be PANI,3i, 10d even though this is not the case. The proof that PANI has been produced can be provided (1) by the observation of a green color under acidic conditions (absorption band in optical spectra with a maximum at about 800 nm) or a blue color under alkaline ones (local absorption maximum at about 630 nm),18 (2) by the determination of a molecular weight above about 10 000 (e.g., by gel‐permeation chromatography),4, 6, 8a, 17c or (3) by finding the conductivity of protonated PANI above about 10 −3 S cm −1 1.…”

Section: Resultsmentioning

confidence: 99%

“…In addition, monodisperse nanospheres with an average diameter of 300 nm were also observed at closer inspection in the background of SEM images. The flower‐like morphology of aniline oligomers20 has also been referred to as dandelion‐like,12l orchid‐like10d, or rose‐like21 in the literature. When the early oxidation products have been separated from the reaction mixture and oxidation was left to proceed, the morphology of solids became granular (Figure 1 B).…”

Section: Resultsmentioning

confidence: 99%

“…The same infrared spectra of the first products producing nanosheets with a flat and well‐ordered morphology and high crystallinity have been reported in the acidity range of approximately pH 5–7 or at low APS/aniline molar ratio by a number of research groups 5. 10h, 22, 29 A flower‐like nanostructure composed of nanodisks using APS as an oxidant without any acid,30 and an orchid‐like morphology at 1:5 molar ratio of p ‐TSA/aniline10d displaying the same FTIR spectra have also been prepared. In these cases, the prepared aniline oligomeric products were incorrectly called “polyaniline”.…”

Section: Resultsmentioning

confidence: 99%

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Self‐Assembly of Aniline Oligomers

Zhao

Tomšík

Wang

et al. 2012

Chemistry An Asian Journal

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A great number of nano/microscaled morphologies have recently been prepared during the oxidation of aniline. At the early stage of oxidation, aniline oligomers are obtained, often in spectacular morphologies depending on reaction conditions. Herein, the flower-like hierarchical architectures assembled from aniline oligomers by a template-free method are reported. Their formation process is ascribed to the self-assembly of oligoanilines through non-covalent interactions, such as hydrogen bonding, hydrophobic forces, and π-π stacking. The model of directional growth is offered to explain the formation of petal-like objects and, subsequently, flowers. In order to investigate the chemical structure of the oligomers, a series of characterizations have been carried out, such as matrix-assisted laser desorption ionization, time-of-flight mass spectrometry, gas chromatography coupled with mass spectrometry analysis, X-ray diffraction, and UV/Vis, Fourier-transform infrared, and Raman spectroscopies. Based on the results of characterization methods, a formation mechanism for aniline oligomers and their self-assembly is proposed.

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A novel orchid-like polyaniline superstructure by solvent–thermal method

Cited by 17 publications

References 32 publications

A Comparative Study on Humidity Sensing Performances of Polyaniline and Polypyrrole Nanostructures

A Comparative Study on Humidity Sensing Performances of Polyaniline and Polypyrrole Nanostructures

Preparation of 2D leaf‐shaped and 3D flower‐shaped sandwich‐like polyaniline nanocomposites and application on anticorrosion

Self‐Assembly of Aniline Oligomers

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