Polyaniline Chitosan Research Articles

Sensitive determination of bisphenol S from food samples using chitosan modified polyaniline: Detection optimization via Box Behnken Design

Increased global awareness and the selective ban on bisphenol A (BPA) toxicity have prompted manufacturers to seek alternatives. Bisphenol S (BPS) emerges as one such alternative for potential food packaging replacement. However, BPS is not exempt from toxicity concerns. In this study, we demonstrate a straightforward method using a polyaniline/chitosan (PANI/Cht) composite drop-coated onto a screen-printed carbon electrode to selectively and sensitively detect BPS in food samples. PANI/Cht sensitivity was optimized through Box Behnken Design, considering factors such as dosage, pH, and contact time. ANOVA analysis highlighted dosage and contact time as significant in sensitive BPS detection. The PANI/Cht sensor exhibits excellent linearity (0.2–50 µM) with a low detection limit of 18.65 nM. Furthermore, the sensor showcases satisfactory reproducibility, selectivity, long-term stability, and recoveries for spiked BPS in real food matrices.

Development of polyaniline/chitosan (PANI/CTS) and TiO2-PANI/CTS nanocomposites as anti-corrosion coatings: Synthesis and characterization

Polyaniline/chitosan (PANI/CTS) and TiO2-PANI/CTS nanocomposites were synthesized via in situ oxidative polymerization and characterized by different spectroscopies techniques. The interaction of PANI with the CTS structure and that of the TiO2 nanoparticles with the PANI/CTS copolymer matrix were confirmed by Fourier transform infrared spectroscopy (FT-IR). X-ray diffraction (XRD) analyses of the synthesized nanocomposites show a crystalline structure like their base materials (CTS, PANI and TiO2). The incorporation of PANI, CTS, and TiO2 in the formation of nanocomposites was confirmed by scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS). Thermogravimetric and differential scanning calorimetry (TGA and DSC) analyses indicate that the PANI/CTS and TiO2-PANI/CTS nanocomposites present greater resistance to thermal decomposition in relation to the CTS and PANI polymers, as well as the highest glass transition temperature (Tg). The anti-corrosion coatings were made by mixing the polymers and synthesized nanocomposites in an alkyd resin (AR) and deposited on 1018 carbon steel and evaluated in 3.5 wt% NaCl solution by linear polarization and electrochemical impedance spectroscopy (EIS) techniques. The best performance against corrosion was observed for the coating made from TiO2-PANI/CTS, since it shows the noblest values in potential, as well as the highest protection efficiencies, even after its immersion for 30 days, which is attributed to the high degree of cross-linking that the nanocomposite has, forming a dense protective film on the steel surface.

Polyaniline-chitosan modified on screen-printed carbon electrode for the electrochemical detection of perfluorooctanoic acid

The overwhelming utilisation of perfluorooctanoic acid (PFOA) for household and industrial applications has posed a severe risk to human health and environmental pollution. Therefore, this study was performed to fabricate a polyaniline-chitosan (PANI-CHT) composite using CHT extracted from crab shells and modified with Screen-Printed Carbon Electrode (SPCE) for the development of an electrochemical sensor to detect PFOA. The physicochemical properties of CHT, PANI, and PANI-CHT were characterised using ATR-FTIR, XRD and SEM-EDX. In addition, the electrochemical performance of the SPCE-modified PANI-CHT 1:1 composite was evaluated through cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Based on the results, PANI-CHT 1:1 showed a linear correlation coefficient of R2 = 0.9954 with a LOD of 1.08 ppb in a linear range of 5–150 ppb. The physicochemical analyses demonstrate the successful blending of CHT with PANI, which enhanced the effective active sites on the surface of SPCE. Upon the practical assessment of the fabricated composite using spiked water samples, the sensor recorded an acceptable recovery percentage range of 96–103 %. Overall, the proposed sensor exhibited great sensitivity, excellent reproducibility, and good stability for the detection of PFOA and with a promising performance.

Effect of polyaniline on the structural, conductivity, and dielectric properties of chitosan

Polyaniline-chitosan (PANI-Cs) blends were prepared by in situ oxidative polymerization with acetic (CH3COOH) acid and hydrochloric (HCl) acid as dopants. Using Fourier transform infrared (FTIR) spectroscopy, the C N and C C stretching of quinoid and benzenoid of PANI in the PANI-Cs blends was confirmed at ranges 1528cm−1 to 1571cm−1 and 1490cm−1 to 1493cm−1, respectively. PANI emeraldine state was stipulated in all samples and PANI-Cs HCl samples have the highest degree of oxidation which is 48.56±0.23%. The ultraviolet-visible (UV–vis) spectroscopy identified the glucopyranose of Cs (282–308 nm), and π−π* transition of benzenoid (389–437 nm) and quinoid rings (551–554 nm) of PANI. The PANI-Cs blends yielded optical band gap values of 1.968±0.014 to 2.009±0.005 eV due to the presence of PANI. One-way ANOVA was also performed, and results showed the significant effect of using different dopants towards the degree of oxidation of the samples. Frequency dependent behavior was observed to the PANI-Cs samples with AC conductivity values around 1.2–4.1 Scm−1 at 105–107 Hz. The 102 Hz dielectric peak intensity of the samples varied due to influence of dopants on charge polarization. Lastly, PANI-Cs samples showed dominance of DC loss and relaxation at low frequencies 10–103 Hz.

Preparation of Multicomponent Biocomposites and Characterization of Their Physicochemical and Mechanical Properties

This work focused on a mutual comparison and characterization of the physicochemical properties of three-component polymer composites. Binary polyaniline–chitosan (PANI–CHT) composites were synthesized by in situ polymerization of PANI onto CHT. Ternary composites were prepared by blending with a third component, polyvinyl alcohol (PVA). Composites with variable PANI:CHT (25:75, 50:50 and 75:25) weight ratios were prepared whilst fixing the composition of PVA. The structure and physicochemical properties of the composites were evaluated using thermal analysis (thermogravimetric analysis (TGA), differential scanning calorimetry (DSC)) and spectroscopic methods (infrared (IR), nuclear magnetic resonance (NMR)). The equilibrium and dynamic adsorption properties of composites were evaluated by solvent swelling in water, water vapour adsorption and dye adsorption isotherms. The electrical conductivity was estimated using current–voltage curves. The mechanical properties of the samples were evaluated using dynamic mechanical analysis (DMA) and correlated with the structural parameters of the composites. The adsorption and swelling properties paralleled the change in the electrical and mechanical properties of the materials. In most cases, samples with higher content of chitosan exhibit higher adsorption and mechanical properties, and lower conductivity. Acid-doped samples showed much higher adsorption, swelling, and electrical conductivity than their undoped analogues.

Chitosan, starch, polyaniline and polypyrrole biocomposite with sugarcane bagasse for the efficient removal of Acid Black dye

Polymeric biocomposites (Polyaniline/sugarcane bagasse (Pan/SB), polypyrrole (PPy/SB), polyaniline/chitosan (PAn/Ch), polyaniline/starch (PAn/St) and polypyrrole/starch (PPy/St)) were prepared and applied for Acid Black-234 (AB-234) dye removal as a function of pH, reaction time, adsorbent dose, initial dye concentration and temperature. The optimum pH for the efficient adsorption for SB, PPy/SB, PAn/SB, PPy/Ch, PAn/Ch, PPy/St and PAn/St were 2, 3, 4, 4, 5, 3 and 3, respectively using adsorbent dose of 0.05 g for the reaction time of 60 min. The pseudo-first-order-kinetic model better explained the biosorption processes of SB, PAn/SB, PAn/Ch, PPy/St and PAn/St, while pseudo-second-order kinetic model better fitted to the kinetic data of PPy/SB and PPy/Ch. It was observed that the biosorption process of dye showed the satisfactory fitness for Langmuir isotherm for the biosorbents with maximum adsorption capacities 52.6, 100, 90.91, 90.0, 71.4, 66.6 and 62.5 for SB, PPy/SB, PAn/SB, PPy/Ch, PAn/Ch, PPy/St and PAn/St, respectively. The thermodynamic study revealed the exothermic nature of adsorption of dye on to biocomposites. Results revealed that polymeric biocomposites are efficient adsorbent and could possibly be used for the adsorption of dyes from textile wastewater.

Ar dielectric barrier discharge jet (DBDjet) plasma treatment of reduced graphene oxide (rGO)–polyaniline (PANI)–chitosan (CS) nanocomposite on carbon cloth for supercapacitor application

A low-temperature (< 42 °C) Ar dielectric barrier discharge jet (DBDjet) is used to treat screen-printed reduced graphene oxide (rGO)–polyaniline (PANI)–chitosan (CS) nanocomposites used as the electrodes of gel-electrolyte supercapacitors. X-ray photoelectron spectroscopy results indicate decreased C–O bonding content, suggesting a reaction with some CS, as well as increased C–N and –COOH contents that could be responsible for the improved hydrophilicity and the resulting enhancement in the capacity of the supercapacitor. Galvanostatic charging discharging measurements indicate that Ar DBDjet treatment improves the capacitance by 166%; these results are confirmed by cyclic voltammetry. Our results demonstrate that without substantial heating, Ar DBDjet reactive plasma species alone can improve the hydrophilicity of rGO–PANI–CS nanocomposites on carbon cloth.

Safeguarding the catalytic activity and stability of polyaniline chitosan silver nanocomposite bound beta-galactosidase against product inhibitors and structurally related compound

In this study, an attempt has been made to evaluate the effect of products of β-galactosidase (βGS) catalyzed reaction i.e. glucose and galactose and their structurally related compound vitamin C (VC) on the catalytic activity of native and PANI-CS-NC and PANI-CS-Ag-NC adsorbed βGS. Results indicated a decline in catalytic activity of soluble enzyme in the presence of all investigated compounds. The order of inhibition was found to be VC < glucose < galactose. However, the immobilized preparations were found more resistant to inactivation caused by the added compounds. About 48% activity was retained by PANI-CS-Ag-NC-βGS in the presence of galactose (5%, w/v), while the native enzyme exhibited only 18% of its original activity. A significant decrease in absorbance and fluorescence intensity was evaluated in soluble enzyme incubated in the presence of all investigated compounds. Three-dimensional fluorescence graphs, CD and FT-IR spectroscopic studies illustrated noteworthy conformational changes in the secondary structure and microenvironment of the soluble enzyme in the presence of VC and tested sugars. These results suggest that both PANI-CS-NC and PANI-CS-Ag-NC bound βGS are more resistant to the exposure caused by the higher concentration of added glucose, galactose, and VC and, therefore, can be effectively utilized for the production of a hassle-free lactose nano-biosensor.

Synthesis and Characterization of Acetic Acid-Doped Polyaniline and Polyaniline⁻Chitosan Composite.

Polyaniline–chitosan (PAni–Cs) composite films were synthesized using a solution casting method with varying PAni concentrations. Polyaniline powders used in the composite synthesis were polymerized using acetic acid as the dopant media. Raman spectroscopy revealed that the PAni powders synthesized using hydrochloric acid and acetic acid did not exhibit significant difference to the chemical features of PAni, implying that PAni was formed in varying concentrations of the dopant media. The presence of agglomerated particles on the surface of the Cs composite, which may have been due to the presence of PAni powders, was observed with scanning electron microscope–energy dispersive X-ray spectroscopy (SEM–EDX). Ultraviolet–visible (UV–Vis) spectroscopy further showed the interaction of PAni with Cs where the Cs characteristic peak shifted to a higher wavelength. Cell viability assay also revealed that the synthesized PAni–Cs composites were nontoxic and may be utilized for future biomedical applications.

Effect of metal ions present in milk on the structure and functional integrity of native and polyaniline chitosan nanocomposites bound β-galactosidase: A multi-spectroscopic approach

β-Galactosidase is vital to dairy industries because it catalyzes the hydrolysis of lactose into glucose and galactose making it useful for lactose intolerant patients to consume milk and its products. The present study demonstrates the effect of metal ions commonly found in milk, namely Zn2+, K+, Ca2+ and Mn2+ on the activity of native and polyaniline chitosan nanocomposites bound Aspergillus oryzae β-galactosidase. In polyaniline chitosan silver nanocomposite adsorbed β-galactosidase, a multi-fold enhancement in catalytic activity was observed in the presence of cocktail of Zn2+, K+, Ca2+ and Mn2+ ions. 3D fluorescence, CD and FTIR studies established significant conformational changes in the secondary structure of polyaniline chitosan silver nanocomposite bound β-galactosidase on addition of metal ions as compared to the native and other bound enzyme. This enhanced catalytic efficiency of the immobilized enzyme in presence of metal ions can promote its economic use for lactose hydrolysis in milk.

Elucidating the binding efficacy of β‐galactosidase on polyaniline–chitosan nanocomposite and polyaniline–chitosan–silver nanocomposite: activity and molecular docking insights

AbstractBACKGROUNDAspergillus oryzae β‐galactosidase (β‐gal; EC 3.2.1.23) was physically adsorbed on polyaniline–chitosan nanocomposite (PANI‐CS‐NC) and polyaniline–chitosan–silver nanocomposite (PANI‐CS‐Ag‐NC). Stability and kinetic studies were assessed, along with reusability and molecular docking interactions.RESULTSAccording to transmission electron microscopy images, the sizes of the respective NCs were found to be in the range of 23–39 and 6–18 nm. The η (effectiveness factor) values for PANI‐CS‐NC‐ and PANI‐CS‐Ag‐NC‐bound β‐gal were calculated to be 0.89 and 1.23, respectively, suggesting an enhancement in the activity of the enzyme in the presence of silver ions. Significant broadening was observed in pH and temperature profiles. Kinetic properties of PANI‐CS‐NC‐ and PANI‐CS‐Ag‐NC‐bound β‐gal showed lower Km, and two‐ and fourfold higher Vmax, respectively, compared to free enzyme. PANI‐CS‐Ag‐NC‐bound β‐gal was able to retain 94% of its initial activity after 10 repeated uses. Circular dichroism analysis revealed conformational changes in the secondary structure of protein upon immobilization. The genotoxic assessment revealed non‐toxic behaviour of both free and enzyme‐bound NC. The rate of lactose hydrolysis at 50 °C exhibited by PANI‐CS‐‐Ag‐NC bound β‐gal was 7% higher than that for the native enzyme. In‐silico analysis showed efficient binding of β‐gal on PANI‐CS‐ NCs due to interaction with residues that were exclusive of the active site of the enzyme.CONCLUSIONPANI‐CS‐Ag‐NC‐bound β‐gal preparation proved to be a robust nano‐biocatalyst due to remarkable enhancement in catalytic activity along with excellent stability and reusability characteristics, which could be further utilized for efficient construction of nano‐biosensors for producing lactose‐free dairy products to feed lactose‐intolerant patients. © 2018 Society of Chemical Industry

Electroconductive 3D polymeric network production by using polyaniline/chitosan-based hydrogel

Herein, polyaniline/chitosan(PANI/CTS)-based electroconductive hydrogel was produced by photocrosslinked network in which CTS was used as a main component. Firstly, glycidyl methacrylate (GMA) was grafted on the CTS backbone to form CTS-g-GMA. Then, a three-dimensional polymeric network consisting of CTS-g-GMA and poly(ethylene glycol)diacrylate (PEGDA) was obtained by using photocrosslinking technique. At last, aniline monomer solution prepared by utilizing three different aniline concentrations (0.08, 0.16 and 0,32 M) was absorbed into (CTS-g-GMA)-PEGDA crosslinked structure to form [(CTS-g-GMA)-PEGDA]-PANI electroconductive semi interpenetrating network. FT-IR, XRD, SEM, TGA analyses and cytotoxicity test were performed for the produced samples. Conductivities of the hydrogels were determined by four-point probe technique. According to the conductivity measurements, among the PANI/CTS-based hydrogels, [(CTS-g-GMA)-PEGDA]-PANI(0.32 M) has the highest conductivity value (7437 × 10−3 S/cm). The obtained results showed that the fabricated electroconductive hydrogel (ECHs) in this study is a promising candidate owing to its advantages for biomedical applications especially biosensors in the future.

A flexible polyaniline-based bioelectronic patch.

Bioelectronic materials based on conjugated polymers are being developed in the hope to interface with electroresponsive tissues. We have recently demonstrated that a polyaniline chitosan patch can efficiently electro-couple with cardiac tissue modulating its electrophysiology. As a promising bioelectronic material that can be tailored to different types of devices, we investigate here the impact of varying the synthesis conditions and time of the in situ polymerization of aniline (An) on the sheet resistance of the bioelectronic patch. The sheet resistance increases significantly for samples that have either the lowest molar ratio of oxidant to monomer or the highest molar ratio of dopant to monomer, while the polymerization time does not have a significant effect on the electrical properties. Conductive atomic force microscopy reveals that the patch with the lowest sheet resistance has a connected network of the conductive phase. In contrast, patches with higher sheet resistances exhibit conductive areas of lower current signals or isolated conductive islands of high current signals. Having identified the formulation that results in patches with optimal electrical properties, we used it to fabricate patches that were implanted in rats for two weeks. It is shown that the patch retains an electroactive nature, and only mild inflammation is observed with fibrous tissue encapsulating the patch.

Biocompatibility Assessment of Conducting PANI/Chitosan Nanofibers for Wound Healing Applications.

As electroactive polymers have recently presented potential in applications in the tissue engineering and biomedical field, this study is aiming at the fabrication of composite nanofibrous membranes containing conducting polyaniline and at the evaluation of their biocompatibility. For that purpose, conducting polyaniline–chitosan (PANI/CS) defect free nanofibres of different ratios (1:3; 3:5 and 1:1) were produced with the electrospinning method. They were characterized as for their morphology, hydrophilicity and electrical conductivity. The membranes were then evaluated for their cellular biocompatibility in terms of cell attachment, morphology and cell proliferation. The effect of the PANI content on the membrane properties is discussed. Increase in PANI content resulted in membranes with higher hydrophobicity and higher electrical conductivity. It was found that none of the membranes showed any toxic effects on osteoblasts and fibroblasts, and that they all supported cell attachment and growth, even to a greater extent than tissue culture plastic. The membrane with the PANI/CS ratio 1:3 supports better cell attachment and proliferation for both cell lines due to a synergistic effect of hydrophilicity retention due to the high chitosan content and the conductivity that PANI introduced to the membrane.

Synthesis of silver-anchored polyaniline–chitosan magnetic nanocomposite: a smart system for catalysis

A novel and smart four component system composed of chitosan, polyaniline, magnetite and silver was exploited for catalysis.

Polyaniline–chitosan nanocomposite: High performance hydrogen sensor from new principle

A high selectivity and response towards hydrogen gas is realized with a composite of polyaniline nanofibers embedded in chitosan matrix. The enhanced response originated from the new sensing mechanism related with the composite nature of chitosan and polyaniline. Based on the high gas sensing performance through nanostructured resistive polyaniline nanofibers, the swelling of chitosan as the matrix distributing among the resistor network controls the hopping conduction between the nanofibers. This gate control of chitosan on the polyaniline conduction claims a new type of sensor mechanism resulting in a reverse polarity in conductivity change with respect to the conductivity change of polyaniline. The response-reversal can enhance the sensing response. Furthermore, the highly enhanced selectivity for hydrogen was also achieved through filtration action of chitosan for large size and polar molecules. We thus demonstrate a new material and structural design of solid state sensor for improvement in selectivity and response.

Batch sorption studies on the removal of fluoride ions from water using eco-friendly conducting polymer/bio-polymer composites

Batch sorption system using eco-friendly conducting polymer/bio-polymer composites viz. polyaniline/chitosan (PANi/Ch) and polypyrrole/chitosan (PPy/Ch) as adsorbents were investigated to ensnare fluoride ions from aqueous solutions. The system variables studied include initial concentration of the sorbate, agitation time, adsorbent dose, pH, co-ions and temperature. The experimental data fitted well to the Langmuir and Freundlich isotherms. The amounts of fluoride ions adsorbed per unit mass of the adsorbents were found to be 5.9 mg/g for PANi/Ch and 6.7 for PPy/Ch, at 50 °C from 10 mg/L fluoride solution. Thermodynamic parameters indicated that the removal of fluoride ions is an endothermic process. FT-IR, X-ray, SEM and EDAX patterns of the polymer composites before and after exposure to fluoride ions suggested that the defluoridation occurs via dopant-exchange mechanism on the N-atoms present in these constituent polymers.

Chitosan/polyaniline hybrid conducting biopolymer base impedimetric immunosensor to detect Ochratoxin-A

Chitosan (CS)–polyaniline (PANI) hybrid conducting biopolymer film was obtained on indium–tin-oxide (ITO) electrode using electrochemical polymerization process. Fourier transform infrared (FT-IR) spectra of PANI–CS had showed covalent and hydrogen binding between PANI and CS molecules. Electrochemical impedance spectroscopy (EIS) measurements had showed low charge transfer resistance ( R CT) of PANI–CS and PANI. Successive rabbit antibody (IgGs) immobilization on PANI–CS, CS and PANI matrixes surface were confirmed with FT-IR and EIS measurements. Ochratoxin-A (OTA) interaction with IgGs had increased R CT values and showed linear response up to 10 ng/mL OTA concentration in electrolyte. Relative change in R CT was higher in PANI–CS due to higher proportion of carboxylic and hydroxyl functionalities at PANI–CS matrix surfaces. The absolute sensitivity of PANI, CS, and PANI–CS were 16 ± 6, 22 ± 9 and 53 ± 8 Ω mL/ng, respectively derived from slope of linear response up to 10 ng/mL with 1 ng/mL minimum detection limit.