Synthesis of Janus polyaniline–polyelectrolyte complex membrane via in situ confined polymerization

Polyelectrolyte complex (PEC) membranes prepared from poly(styrene sulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDADMAC) were modified by crossflow polymerization of aniline (ANI). The PEC membranes were used as separators in a two-compartment setup where ANI monomer and ammonium persulfate (APS) oxidant diffused through the membranes to form polyaniline (PANI). APS and ANI having different distributions throughout the membranes, the reaction led to the asymmetric polymerization of PANI on one face of each PEC membrane thus producing Janus membranes. Due to the excess PANI content, the membrane displayed distinct asymmetric electrical conductivities on each face. Interestingly, very different ANI polymerizations were obtained when nonstoichiometric PEC membranes having different molar ratio of cationic and anionic polyelectrolytes (P⁺:P^? represents PDADMAC:PSS) were used and transport of APS was fastest through the 2:1 PEC when compared to the 1:2 PEC. In all experiments, the polymerization was most intense on the ANI side of the membranes. Also, the influence of NaCl both during PEC fabrication and during polymerization was studied and found to have some effect on the solute permeability. Results showed that a higher content of PANI was formed on PEC membranes having excess P⁺ and with no NaCl added during PEC fabrication. Although X-ray diffraction confirmed the presence of PANI on both sides of each membrane, scanning electron microscopy images demonstrated that both sides of each membrane had different PANI content deposited. Electrical conductivity measurements using a four-point probe setup also showed that the PEC–PANI exhibits asymmetric electrical property on different sides. © 2021 Society of Industrial Chemistry.     

Optimization of waste quail eggshells as biocomposites for polyaniline in ammonia gas detection

A simple, cost-effective, and novel chemical sensor for ammonia (NH₃) gas detection was developed from polyaniline (PANI)/quail eggshell (QES) composites. QES is a natural waste enriched in calcium carbonate. In this work, pure PANI was synthesized from chemical oxidation method and PANI/QES composites were prepared from physical mixing of QES with the synthesized PANI at different mass ratio. A series of complementary techniques including Fourier transform infrared and ultraviolet-visible spectrometers, scanning electron microscope with energy dispersive detection coupled with mapping, thermogravimetric analysis, and X-ray diffractometer were used to characterize the physicochemical and textural properties of the biocomposites. From the results, PANI/QES composite with a mass ratio of 1 exhibited the lowest NH₃ detection limit of 5.24 ppm with a linear correlation coefficient (R²) of close to unity (0.9932) between the signal and NH₃ gas concentration. As a whole, the PANI/QES biocomposites synthesized from this work exhibited excellent selectivity toward NH₃ gas even in the presence of other gas impurities, such as acetone, ethanol, and hexane. For the sensor reusability, the PANI/QES biocomposites can be reused in the application of NH₃ gas detection for at least 4 cycles.     

Improving ultraviolet light photocatalytic activity of polyaniline/silicon carbide composites by Fe-doping

It was aimed to prepare polyaniline (Pani) composites, including silicon carbide (SiC) nanofibers doped with iron (Fe) ions. The Fe-doping of SiC was performed to enhance the photocatalytic activity of the composites through the separation of photoexcited mobile charge carriers. For comparison purposes, Pani composites were also prepared with undoped SiC nanofibers. The composite samples were characterized by FTIR, XRD, SEM, EDX, and UV–Vis spectroscopies. Experiments on photocatalytic degradation of methylene blue under ultraviolet light irradiation revealed that Pani/SiC-Fe composites exhibited higher photocatalytic activity when compared with Pani/SiC composites. Almost 22% dye removal was obtained within 300 min with the Pani composite, containing 15 wt.% SiC-Fe. FTIR, XRD, SEM, EDX, and UV–Vis spectroscopies demonstrated that SiC nanofibers were successfully doped with iron ions and incorporated into the polyaniline matrix. The original aspect of this study was to research the photocatalytic activity of polyaniline composites containing Fe-doped SiC nanofibers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48524.     

Sonochemical synthesis of PANI-BiVO4-GO semiconductor nanocomposite highly efficient visible-light photocatalytic performance

Abstract

Polyaniline/Bismuth Vanadate/Graphene Oxide (PANI-BiVO₄-GO) or BGPA composite was prepared by sonochemical deposition of bismuth vanadate-graphene oxide (BiVO₄) nanoparticles on the surface of polyaniline (PANI). The best photocatalytic degradation performance was obtained by 5wt% BGPA composites for MB, RhB, and SO dyes, which is approximately 4 times higher than that of 1% BGPA. Meanwhile, the photocatalytic stability of BiVO₄ was significantly improved by introducing PANI into the PANI-BiVO₄-GO composite. The dramatic promotion of the photocatalytic degradation performance and the photocatalytic stability can be attributed to the formation of a heterojunction free electron between PANI and BiVO₄-GO. The existence of those extra free electrons can dramatically enhance the efficiency of the photogenerated electrons, which accelerate the transfer of photogenerated holes from BiVO₄-GO to PANI, and therefore inhibit the self-oxidation of BiVO₄.     

Tungsten Nitride,Well‐Dispersed on Porous Carbon: Remarkable Catalyst,Produced without Addition of Ammonia,for the Oxidative Desulfurization of Liquid Fuel

Polyanilines (pANIs), loaded with phosphotungstic acid (PTA), are pyrolyzed to get WO₃ or W₂N (≈6 and ≈7 nm, respectively), which is well‐dispersed on pANI‐derived porous carbons (pDCs). Depending on the pyrolysis temperature, WO₃/pDC, W₂N/pDC, or W₂N‐W/pDCs could be obtained selectively. pANI acts as both the precursor of pDC and the nitrogen source for the nitridation of WO₃ into W₂N during the pyrolysis. Importantly, W₂N could be obtained from the pyrolysis without ammonia feeding. The obtained W₂N/pDC is applied as a heterogeneous catalyst for the oxidative desulfurization (ODS) of liquid fuel for the first time, and the results are compared with WO₃/pDC and WO₃/ZrO₂. The W₂N/pDC is very efficient in ODS with remarkable performance compared with WO₃/pDC or WO₃/ZrO₂, which is applied as a representative ODS catalyst. For example, W₂N/pDC shows around 3.4 and 2.7 times of kinetic constant and turnover frequency (based on 5 min of reaction), respectively, compared to that of WO₃/ZrO₂. Moreover, the catalysts could be regenerated in a facile way. Therefore, W₂N/pDC could be produced facilely from pyrolysis (without ammonia feeding) of PTA/pANI, and W₂N, well‐dispersed on pDC, can be suggested as a very efficient oxidation catalyst for the desulfurization of liquid fuel.     

煤大分子酸掺杂聚苯胺的机理研究

聚苯胺的酸掺杂一直都集中在小分子无机酸和长链或是带有芳环的小分子有机酸方面，又对反应过程的研究甚少．选择烟煤作为一种煤大分子酸掺杂剂对苯胺聚合过程中的酸度和温度变化进行跟踪，并运用FTIR分析产物的结构．结果表明，煤与聚苯胺间存在较强的物理化学作用，煤掺杂制备聚苯胺的聚合机理随煤含量的变化有所差异，并且聚苯胺的导电机制仍属于极化子机制．     

聚苯胺/环氧树脂导静电涂料的研制

以聚苯胺(PAn)为导电填料,聚酰胺为固化剂,制备聚苯胺/环氧树脂导静电涂料。以冲击强度为考核指标,通过正交设计优化聚苯胺的加入量、固化剂的加入量和固化温度等参数。结果表明,聚苯胺的加入量影响较显著,固化剂的加入量影响也较明显,固化温度的影响较小。较佳的工艺条件为:聚苯胺的加入量为10%,固化剂的加入量为4%,固化温度为40℃。该条件下制得的涂膜附着力达到1级,硬度达2 H,冲击强度达50 cm,电阻率达106Ω.cm,并具有良好的物理化学性能,各项指标完全满足抗静电涂料的要求。     

聚苯胺防腐涂料在金属防护中的应用

综述了近年来国内外聚苯胺在金属腐蚀防护领域的研究状况。介绍了聚苯胺防腐涂层的制备方法、防腐机理。提出了聚苯胺防腐涂料目前存在的问题和今后的研究方向。     

PAn/Ni电磁屏蔽复合材料的研究

聚苯胺作为一种新型导电高分子材料,由于其质轻、环境稳定性好等特点,有应用于电磁屏蔽领域的巨大潜力.对一种先进的电磁屏蔽复合材料--导电聚苯胺PAn/Ni电磁屏蔽涂料进行研究,将高分子材料与金属粉末作为复合导电填料应用于涂料,并研制出在30～1000 MHz内屏蔽效能达60 dB的屏蔽涂料.通过对不同的组分和比例所得涂料的屏蔽效能测试,发现PAn与Ni粉之间在涂料中有复合效应存在.     

Polymer brush coatings for combating marine biofouling

A variety of functional polymer brushes and coatings have been developed for combating marine biofouling and biocorrosion with much less environmental impact than traditional biocides. This review summarizes recent developments in marine antifouling polymer brushes and coatings that are tethered to material surfaces and do not actively release biocides. Polymer brush coatings have been designed to inhibit molecular fouling, microfouling and macrofouling through incorporation or inclusion of multiple functionalities. Hydrophilic polymers, such as poly(ethylene glycol), hydrogels, zwitterionic polymers and polysaccharides, resist attachment of marine organisms effectively due to extensive hydration. Fouling release polymer coatings, based on fluoropolymers and poly(dimethylsiloxane) elastomers, minimize adhesion between marine organisms and material surfaces, leading to easy removal of biofoulants. Polycationic coatings are effective in reducing marine biofouling partly because of their good bactericidal properties. Recent advances in controlled radical polymerization and click chemistry have also allowed better molecular design and engineering of multifunctional brush coatings for improved antifouling efficacies.