Polyaniline Nanomaterials Research Articles

Modulating interfacial polymerization by combination of organic phase additives and trimesoyl chloride for preparing high-performance thin-film nanocomposite reverse osmosis membranes

Incorporating hydrophilic nanoparticles into organic phase during interfacial polymerization (IP) to establish covalent bonds with organic phase monomers has proven to be a successful approach for fabricating high-performance thin-film nanocomposite (TFN) reverse osmosis (RO) membranes. However, the effect of covalent bonds number on the membrane structure and properties remains uncertain. Herein, hydrochloric acid doped polyaniline (PANI-HCl) with a small amount of amine groups and inherent polyaniline (PANI-base) nanomaterials with a larger amount of amine groups were prepared as organic phase additives for preparing high-performance TFN RO membranes. The amine groups on the nanoparticles can bond covalently with the acyl chloride groups of trimethyl chloride (TMC), leading to the accumulation of TMCs at organic/aqueous interface and accelerates IP reaction rate, resulting in a thinner, denser polyamide layer with more leaf-like structures and free volume. The water permeance of the PANI-base-RO membrane was improved by 62.5 % from 0.8 to 1.3 Lm−2h−1bar−1, and the NaCl rejection was improved from 97.6 % to 99.4 % compared with the pristine membrane. Overall, this work highlights the beneficial impact of organic phase additives with more amine groups on enhancing the desalination performance of RO membranes, providing valuable insights for the structural design of additives and dispersing medium selection.

Employing NaYF4: Yb, Tm upconversion particles (UCPs) in combination with rGO and PANI nanomaterials for the fabrication of radiation-curable anticorrosion composites/coatings

Upconversion particles (UCPs) able to emit photons from the ultraviolet to near-infrared (NIR) region of the electromagnetic spectrum when excited by a NIR laser may be used as internal radiation sources for the manufacture of thick composites with uniform and deep polymerization. In this work, NaYF4: Yb, Tm-based UCPs were synthesized and employed to cure composites using a dual curing method via UV and blue light produced from the UCPs to activate the photo-initiators (PIs), and the resulting cure depth and degree of double bond conversion (DC) were measured. In addition, the influence of UCP content and laser power on cure depth and DC was investigated. The emission rate of the UCPs demonstrated a non-linear, wavelength-specific relationship with increasing laser power and exposure time. Using optimal conditions, 62 % DC with a 2.5 cm cure depth was achieved. For the first time, the ability of UCPs to cure composites in the presence of reduced graphene oxide (rGO) and polyaniline (PANI) nanoparticles was studied. Results indicated that DC was almost consistent across samples (except the sample containing 1 wt% rGO), although the addition of nanomaterials decreased DC and cure depth. The addition of 0.5–0.5 wt% rGO-PANI increased the nanocomposites' compressive strength and strain at failure by 66 and 37 %, respectively. The nanocomposite formulations were applied to steel and the anti-corrosion properties were also investigated. The findings revealed low-frequency impedance (|Z|10 mHz) numbers higher than 1010 Ω.cm2 up to 4 w immersion duration, proving this coating's exceptional barrier anti-corrosion capabilities.

Construction of polyaniline/MnO2 core-shell nanocomposites in carbonized wood tracheids for high-performance all-solid-state asymmetric supercapacitors

Polyaniline (PANI) nanomaterials or carbon nanotubes (CNTs) are first synthesized on the tracheid wall of activated wood carbon (AWC) to obtain PANI@AWC and CNT@AWC, respectively. Then MnO2 nanosheets are electrodeposited on the outer surface of the PANI nanomaterials to form a core-shell structure. The introduction of PANI in wood tracheids not only increases the loading of MnO2, but also improves the electrical conductivity and structural stability, and the core-shell structure can synergistically store energy. Then using the MnO2/PANI@AWC composite electrode as an anode and using CNT@AWC as a cathode, a high-performance all-solid-state asymmetric supercapacitor with high energy density and high cycling stability is successfully constructed. This supercapacitor has a wide working voltage of 0–1.8 V and a high energy density of 0.875 mWh cm−2 at 9 mW cm−2. The capacitance retention rate is as high as 93.21 % after 10,000 charge-discharge cycles. Therefore, wood-based composites with aligned tracheids have great potential in the development of high-power and high-energy-density energy storage devices.

Fabrication of conductive polyaniline nanomaterials based on redispersed cellulose nanofibrils

Dewatering or drying of diluted cellulose nanofibril suspensions is an effective way for reducing the costs of transportation and storage. In this study, poly(vinylpyrrolidone) (PVP) was introduced into a redispersing system of concentrated CNFs, and the obtained redispersed CNFs were used for fabricating CNF/PANI (polyaniline) nanomaterials by in situ polymerization method. The results showed that mechanical grinding with grinding gap of − 20 μm was an effective way to redisperse the concentrated CNFs, especially when the PVP was added in the redispersing process. The conductivity of the redispersed CNF/PANI film reached 1.08 S/cm and the specific capacitance reached 118.3 F/g (at 0.3 A/g), when the concentrated CNFs were redispersed with 5% PVP. During the polymerization process, PVP facilitated the PANI coating on the CNFs uniformly as steric stabilizer. This study provided a basis for the application of redispersed CNFs in conductive nanomaterials area.

Room Temperature Operating, Fast and Reusable Polyaniline Sensor Synthesized Ultrasonically Using Organic and Inorganic Acid Dopants

In this paper we report a simple, green method for synthesis of polyaniline (PANI) nanoparticles by chemical oxidative polymerization with the assistance of ultrasonic irradiation. The polyaniline nanomaterials were synthesized with several organic acid dopants (tartaric acid (C4H6O6) and oxalic acid (C2H2O4)) and inorganic acid dopants (hydrochloric acid (HCl) and perchloric acid (HClO4)). A comparative study of the effect of the organic and inorganic acid dopants on the sensing properties of PANI for ammonia (NH3) vapors at room temperature was performed. It was observed that the electrical properties of the doped PANI depended on the type of the acid dopant. A remarkable change in resistance was observed upon doping with the different acid dopants. Structural and morphological studies and composition analysis were performed by UV-visible, FTIR, XRD and SEM techniques. The highest conductivity was obtained for PANI with HClO4 acid dopant while the lowest conductivity was obtained for PANI with tartaric acid dopant. The results showed that PANI doped with tartaric acid was an excellent sensor with fast response time and an enhanced sensitivity (26.1% for 5 ppm and 56% for 100 ppm) for NH3 gas at room temperature. PANI doped with organic acids showed faster recovery following NH3 treatment as compared to PANI doped with inorganic acid dopants. The PANI doped with tartaric acid sensor showed excellent stability for 350 days. In summary ultrasonic irradiation and the nature of the dopants showed significant effects on enhancing the sensing performance.

Evaluation of membrane tailored with biocompatible halloysite‒polyaniline nanomaterial for efficient removal of carcinogenic disinfection by‒products precursor from water

Humic acid (HA) is the main component of natural organic matter that generates carcinogenic by‒products during disinfection and its removal from water resources is challenging. Biocompatible halloysite (HNTs) nanomaterial decorated with polyaniline (HNTs‒PANI) was synthesized via polymerization technique. HNTs‒PANI was added to prepare polyethersulfone mixed matrix membranes (MMMs). The influence of HNTs‒PANI concentration on HA removal efficiency was studied by varying the HNTs‒PANI (0.5, 1 and 1.5 wt%). The characterization studies of MMMs revealed that the addition of HNTs‒PANI improved the morphology of the membranes, surface properties, chemical stability and thermal property. The amine and hydroxyl groups within the MMMs improved the membrane wettability. The addition of HNTs‒PANI within the MMMs had significantly enhanced the pure water flux and HA filtration. YHP2 MMM with 1 wt% of HNTs‒PANI demonstrated sieving coefficient of 0.10 and the highest HA removal efficiency of 91% greater than the neat PES membrane. Furthermore, the antifouling property of the MMMs was studied using HA as foulant. 1 wt% of HNTs‒PANI added MMM showed a high flux recovery ratio (94.9%) with low total fouling of 12% and low irreversible fouling of 5%, respectively. Thus, HNTs‒PANI was an efficient nanomaterial for enhancing the pure water flux, removal efficiency and antifouling property to treat water contaminated with HA.

Chloride ion storage performance of polyaniline/graphene nanocomposite in aqueous sodium chloride solution

The use of anion storage materials has played an important role in the development of electrochemical energy storage systems and water desalination. Herein, the graphene-supported polyaniline (PANI/GN) nanomaterial is developed as a new chloride ion storage electrode in aqueous sodium chloride solution. The as-prepared PANI/GN electrode exhibits highly reversible electrochemical stability in both a three-electrode system and a full desalination battery using a sodium ion storage electrode. Competitive electrochemical properties with a reversible capacity of 126 mA h g−1, a coulombic efficiency of more than 95 % and a high rate capability are achieved for the PANI/GN electrode compared to the previously reported electrodes of metals, antimony oxychloride, and polypyrrole. The anionic chloride species instead of covalent chloride species in the as-prepared PANI/GN is demonstrated to be electrochemically active.

Optimization and thermal effects of polyaniline nanomaterial synthesized by chemical oxidative polymerization method


 
 
 Scientific zone has a great attention to the polyaniline (PANI) nanomaterials which is an organic, conductive and a conjugated polymer. It has variety of applications such as in batteries, microelectronics displays, antistatic coatings, electromagnetic shielding materials and actuators. PANI was synthesized by using chemical oxidative polymerization method. The preparation process carried out by the main reagent aniline (C6H7N) with the ammonium peroxydisulpate (APS) ((NH4)2S2O8) which act as an oxidant and hydrochloric acid (HCL) as a dopant in an ambient temperature. The synthesized polymer materials are annealed at different temperatures such as 200°C,300°C and 400°C. After annealed treatment, the weight percentage of polymer material are changed were decreases with increase the temperature of pure PANI (0.441g),200°C(0.172g), 300°C(0.147g), 400°C (0.105g). Then the obtained polymer materials are characterized by FTIR, UV-Visible, Particle size analysis (PSA) and Antibacterial analysis. FTIR is used to determine the functional group of polymer nanomaterials. UVVisible exhibits the quantitative information about the polymer nanomaterials by using its band gap. The size of the individual particles and the size distribution range of the respective samples are determined by the Particle Size Analyzer (PSA). Antibacterial activity is used to find the polymer nanomaterials which kills bacteria, or bacteriostatic,which slow down the growth of bacteria. These profiling techniques are used to find the properties like functional group, quantitative information, particle size, antibacterial activity of respective polyaniline nanomaterial samples.
 
 

Influence of annealing temperature on optical, chemical and particle size properties of polyaniline nanomaterial


 
 
 Polyaniline is a representative conducting polymer because of its high electrical conductivity in doped state and it’s used in various fields of science and engineering because of its unique characteristics. Polymers are playing a dominant role in many areas such as material sciences, textile industries and chemical industries. Monomers of aniline are combined together to form a polymer of polyaniline by chemical oxidative polymerization method. The process of synthesis includes 1.5 M of aniline (C6H5N) as main reagent which causes chemical reaction, Sulfuric acid (H2SO4) as a dopant which alters its original electric and optical properties and Ammonium Peroxydisulfate (APS) as an oxidant which has the ability to oxidize and accept electrons. The synthesized nanoparticles are subjected to heating process at two different temperatures (200˚C and 400˚C). The prepared polymer material is characterized by UV-Visible Spectroscopy,Fourier Transform Infra-Red Spectroscopy, Particle Size Analyzer and antibacterial activity. The electron transition from ground state to excited state was revealed by UVVis Spectroscopy. Polymeric materials are identified using FTIR spectroscopy and it also exhibits the chemical bonds and structure of the sample. Particle Size Analyzer represents the mean size of the polyaniline sample. The overwhelming potential application of polyaniline includes manufacturing of circuit board, corrosion resistance, and fabrication of smart textiles.
 
 

Synthesis and characterization of polyaniline nanomaterials with different molar ratio of monomer


 
 
 Formation of polymer nanomaterials are achieved by the process of polymerization and there was an availability of different methods such as chemical oxidative polymerization,electro chemical polymerization, In-situ oxidative polymerization and emulsion polymerization etc., Many monomers combine to form polymers under certain conditions by chemical reactions between the monomers. The chemical oxidative polymerization was most commonly used method to synthesize PANI and the synthesis process involved various molar ratio of aniline (0.1M, 0.2M, 0.3M) in which APS was used as an oxidant with dopant of HCl. This study revealed that the properties changed based on their initial conditions. The prepared aromatic polyaniline was characterized by FT-IR, UV-VIS,Particle size analyzer techniques and anti-bacterial activity of the sample was analyzed.FT-IR spectroscopy gives deep view of many functional groups that were present in a system by measuring vibrational frequencies of chemical bonds involved. UV-VIS was a good tool to identify, characterize and to study the optical properties of nanomaterials.In particle size analyzer, the size of a particle was measured using the instrument laser diffraction particle size analyzer (SALD-2300). The synthesized polyaniline had the tendency to resist the growth of both gram positive and gram negative bacteria. These organic conducting polymers were sometimes called “smart polymers” and have varies application in medical, OLED, solar cell, batteries and sensor etc.,
 
 

Normal and reverse AOT micelles assisted interfacial polymerization for polyaniline nanostructures

We report here the synthesis of polyaniline (PANI) nanomaterials using sodium bis (2-ethylhexyl) sulfosuccinate (AOT) micelles assisted chemical oxidative interfacial polymerization. We have employed two interfaces (chloroform-water and hexane-water) and two oxidizing agents (ammonium persulfate and ferric chloride). The anionic surfactant sodium bis (2-ethylhexyl) sulfosuccinate (AOT) forms normal micelles in aqueous solution and reverse micelles in hydrophobic solvents like hexane or chloroform. The factors influencing the properties and morphologies of polyaniline nanomaterials such as monomer: surfactant ratio, monomer: oxidant ratio, types of interfaces and oxidants used have been studied. Powder X-ray diffraction of the polyaniline nanomaterials have revealed that polyaniline samples were semi-crystalline in nature. Morphology of polyaniline samples studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have revealed that most of the polyaniline nanomaterials synthesized using ferric chloride possess spherical nature, whereas polyaniline samples synthesized using ammonium persulfate (APS) possess short nanofibers especially at lower aniline/AOT mole ratio in feed (12.5–6.5). The four probe electrical conductivity of the samples were found to be of the order of 1.8 × 10−1 to 8.6 × 10−1 S/cm. Thermal stability of the polyaniline samples recorded by thermogravimetric analysis (TGA) have revealed that polyaniline samples were thermally stable up to 275 °C for 10% weight loss. Interfacial polymerization of aniline monomer using reverse micelles of AOT in hexane phase and ammonium persulfate as oxidizing agent in aqueous phase have been proved to be efficient method for the synthesis of short polyaniline nanofibers.

Some Important Issues of the Commercial Production of 1-D Nano-PANI.

One-dimensional polyaniline nano-materials (1-D nano-PANI) have great promise applications in supercapacitors, sensors and actuators, electrochromic devices, anticorrosive coatings, and other nanometer devices. Consequently, commercial production of 1-D nano-PANI at large-scale needs to be quickly developed to ensure widespread usage of this material. Until now, approaches—including hard template methods, soft template methods, interfacial polymerization, rapid mixing polymerization, dilute polymerization, and electrochemical polymerization—have been reported to be used to preparation of this material. Herein, some important issues dealing with commercial production of 1-D nano-PANI are proposed based on the complexity of the synthetic process, its characters, and the aspects of waste production and treatment in particular. In addition, potential solutions to these important issues are also proposed.

Fabrication of high performance printed flexible conductors by doping of polyaniline nanomaterials into silver paste

An innovation application of doping conjugated polyaniline nano-dendrites (PANIs) into electrical conductive composites (ECCs) to prepare advanced flexible or stretchable printing circuits with better electrical conductivity and mechanical stability.

Synthesis and biocompatibility assessment of polyaniline nanomaterials

To investigate the biocompatibility of polyaniline nanomaterials as the drug carrier, polyaniline nanospheres with high-molecular weight (Mw ~48,000) and nanofibers with low-molecular weight (Mw ~4000) were prepared and cytotoxicity, acute oral toxicity test, and histopathology examination were performed. Cytotoxicity test showed that both nanofibers and nanospheres were quite toxic to BV2 microglia cells at higher concentration and the former were more toxic than the latter. No clear sign of acute toxicity was found after oral administration. However, histopathology section demonstrated slight liver damage present when administrated polyaniline nanofibers with 100 mg/mL. The results revealed that the higher of the molecular weight, the lower toxicity it had. Preparing polyaniline with higher molecular weight may be one of the methods to obtain polyaniline with good biocompatibility. The results gave a better understanding of biocompatibility of polyaniline nanomaterial and made it more practical in medical field.

Synthesis and Properties of Fe<sub>3</sub>O<sub>4</sub>/Polyaniline Nanomaterial and Its Ability of Removing Arsenic in Wastewater

Synthesis and Properties of Fe<sub>3</sub>O<sub>4</sub>/Polyaniline Nanomaterial and Its Ability of Removing Arsenic in Wastewater

Polyaniline films with modified nanostructure for bifunctional flexible multicolor electrochromic and supercapacitor applications

The flexible polyaniline (PANI) thin films with modified nanostructure are prepared on flexible indium tin oxide (ITO)/polyethylene terephthalate (PET) substrates by combination of galvanostatic and cyclic voltammetric electrodeposition techniques. The electrochemical properties of as-prepared PANI nanomaterials are investigated by using the PANI film as an active material of the electrode for primary electrochromic device and electrochemical supercapacitor. This film presents a remarkable mechanical flexibility, high coloration efficiency of 80.9 cm2 C−1 at 630 nm and noticeable multicolor performances with reversible color change of transparent, pale yellow, green, blue and blue-purple. Further, a smart supercapacitor is presented, and the level of energy storage can be monitored by the change of optical performance. The film displays the highest specific capacitance of 473.3 F g−1 at the scan rate of 0.03 V s−1. The high-performance PNAI film exhibits promising features for various emerging flexible and multicolor electronics and optoelectronic devices combining energy storage and electrochromism.

Facile Synthesis of Polyaniline Nanotubes Using Self-Assembly Method Based on the Hydrogen Bonding: Mechanism and Application in Gas Sensing.

Based on hydrogen bonding, the highly uniform polyaniline (PANI) nanotubes were synthesized by self-assembly method using citric acid (CA) as the dopant and the structure-directing agent by optimizing the molar ratio of CA to aniline monomer (Ani). Synthesis conditions like reaction temperature and mechanical stirring were considered to explore the effects of hydrogen bonding on the morphologies. The effects of CA on the final morphology of the products were also investigated. The as-synthesized CA doped polyaniline (PANI) nanomaterials were further deposited on the plate electrodes for the test of gas sensing performance to ammonia (NH3). The sensitivity to various concentrations of NH3, the repeatability, and the stability of the sensors were also tested and analyzed. As a result, it was found that the PANI nanomaterial synthesized at the CA/Ani molar ratio of 0.5 has highly uniform tubular morphology and shows the best sensing performance to NH3. It makes the PANI nanotubes a promising material for high performance gas sensing to NH3.

Growth of polyaniline nanomaterials in rapid-mixing polymerization

The morphology and microstructure of polyaniline (PANI) nanomaterials during the rapid-mixing polymerization were investigated with different oxidants and polymerizing times, as well as their yields, electrical conductivities and electrochemical performance. Extending the polymerizing time, the PANI nanofibers synthesized with ammonium peroxydisulfate (APS) became thicker and aggregated, but remained their original length; the PANI nanorods synthesized with FeCl3 grew from nanorods into nanofibers and kept their primary diameter; while the surface of the PANI nanofibers synthesized with H2O2/Fe2+ become rougher as a coralloid morphology. For all three cases, the yields of the PANI nanomaterials increased, while their electrical conductivities and specific capacitances decreased with prolonging the polymerizing time, especially from 12h to 24h. The PANI nanorods synthesized with APS within 12h possessed the best comprehensive performance.

Synthesis of uniform polyaniline nanosheets and nanotubes: Dependence of morphology on the pH

Polyaniline (PANI) nanomaterials were synthesized by simplified template-free method with ammonium persulfate (APS) as an oxidant. The strong dependence of morphology of polyaniline on the initial pH of the reaction solution has been found. PANI morphology transformed from nanosheets to nanotubes with the decreasing initial pH from 6.70~6.50 to 5.30~5.00, and nanotubes changed further to irregular granules with the decreasing pH lower than 2.26. Polyaniline nanosheets were highly crystalline (2θ=6.2°) but poor in conductivity (5.7×10-5 S/cm) and electroactivity due to low doping level. Though polyaniline nanotubes were poorly crystalline, it had a relative high conductivity (3.4×10-2 S/cm) and maintained the electroactivity in acidic and neutral media which had potential applications in biomedical fields such as tissue engineering and biosensor.

Green Synthesis of Novel Polyaniline Nanofibers: Application in pH Sensing.

An optically active polyaniline nanomaterial (PANI-Nap), doped with (S)-naproxen, was developed and evaluated as a potent pH sensor. We synthesized the material in one pot by the addition of the dopant, (S)-naproxen, prior to polymerization, followed by the addition of the oxidizing agent (ammonium persulfate) that causes polymerization of the aniline. This green chemistry approach allowed us to take only 1 h to produce a water-soluble and stable nanomaterial. UV-visible spectroscopy, fluorescence spectroscopy, FT-IR spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the designed nanomaterial. This nanomaterial exhibited excellent pH sensing properties and showed long term stability (up to one month) without loss of sensor performance.