Polymer Polyaniline Research Articles

Polyelectrolyte complex membranes for zinc-ion cathode by polymerization of polyaniline

Although lithium batteries dominate the rechargeable battery market, concern over safety and material supply have motivated scientists to develop non-lithium-based alternative such as zinc-ion batteries (ZIBs). This work focuses on the development of polyelectrolyte complex-based cathode for ZIBs using a mild aqueous electrolyte such as ZnCl2 instead of KOH and to be further developed into wearable electronics. Composite polyelectrolyte complex electrodes with carbon black and polyaniline (PANI), or manganese oxide (MnO2) as active materials were prepared. The membranes were then further modified by electropolymerization of PANI to enhance the battery performance. Results show that electropolymerization leads to a threefold increase in ZIB performance with increased current density, power density, and specific energy capacity. Zinc chloride (ZnCl2; 1 m) was used as a mild electrolyte instead of potassium chloride (KOH; 6 m) leading to a reduced performance yet allowing for potential use in skin contact and wearable electronics. All the membranes were assembled into ZIB and tested using the battery testing machine. Scanning electron microscopy was used to observe the morphology of the electropolymerized PANI while attenuated total reflection Fourier transform infrared spectroscopy was used to confirm the chemical nature of PANI.

Multi-functional flexible PANI-based material for the development of efficient heating sensing equipment: integrating intelligent heating, motion detection, moisture absorption and ultraviolet protection function

With the advancement of technology and the improvement of living standards, multifunctional composite materials are increasingly attracting attention. Conductive polymer polyaniline (PANI), a key component in the fabrication of intelligent composite materials, is widely used in various fields because of its unique properties. When FeCl3 was used as the oxidant, the PANI-based composite material demonstrated a significant increase in maximum saturation temperature from 34.10 °C to 47.43 °C, under a voltage range of 6–12 V. It also exhibited a sensitivity of 1.0960 kPa−1 (greater than 1 kPa−1) at a low pressure of 0.5 kPa, and its response/recovery time is 200 ms for both. Its maximum capillary rise height reached 7.7 cm. Additionally, the PANI-based composite material achieved a UPF value 40+, effectively blocking over 97.5 % of ultraviolet rays. It also absorbed over 90 % of electromagnetic waves within the 0–18 GHz frequency range. The wear resistance has also been significantly improved compared to pure cotton fabrics, with the friction times reaching 1370 before damage when FeCl3 is used as the oxidant for this composite material. The PANI-based composite material developed in this study functions of intelligent heating, motion detection, moisture absorption, and UV protection functions. It holds the potential to develop efficient heating and sensing devices, offering a solution for the design of the next generation of multifunctional flexible composite materials.

Preparation and infrared shielding of polyaniline@MWCNTs flexible electrochromic device based on cotton fabric

Electrochromic fabric was formed by interfacial polymerization of polyaniline (PANI) and multi-walled carbon nanotubes (MWCNTs) on the surface of cotton cloth. The morphology and properties of the composite films were controlled by changing the content of multi-walled carbon nanotubes. The electrochromic properties of the fabric and its application in the field of near-infrared thermal shielding were studied. It is found that the electrochromic fabric with MWCNTs have better electrochemical and color-changing properties. Electrochromic fabrics achieve color changes from light yellow to yellow-green to dark green in the voltage range of -1.0 to 1.2V, and maintain a fast color switching time (2.15s for coloring, 1.89s for bleaching) after 600 cycles. The reflection contrast (ΔR) at 500nm is 23.01%. Moreover, the electrochromic devices are assembled with fabrics. The device has obvious discoloration and good bending stability. In addition, the thermal shielding is realized by using their reflection characteristics in the visual-near-infrared region. The results show that the electrochromic device has a low surface temperature at different environmental condition, and the thermal reduction from the original state to the bleached state is up to 3.8 ° C, indicating the potential application of the device in thermal regulation.

Design of large-spacing, high-stability PANI-NixV2O5 nanobelts as cathode for aqueous zinc-ion batteries using an organic-inorganic co-embedding strategy

Aqueous zinc-ion batteries (AZIBs), distinguished by their high safety and cost-effectiveness, hold significant promise for grid-level energy storage systems. However, the strong interactions between zinc ions and the host lattice of materials lead to suboptimal cycling stability and rate performance. To address this, we present a novel superlattice structure incorporating conductive polymer (PANI) and metal cation (Ni2+) double interlayers, which can be utilized as cathodes for AZIBs. The incorporation of the conductive host polymer polyaniline (PANI) reduces the valence state of vanadium, enhances the electrical conductivity, and effectively expands the channels for zinc ion insertion. Additionally, metal cations (Ni2+) can effectively induce the synergistic interactions with zinc ions, thereby mitigating the electrostatic interactions with the V2O5 host. Consequently, the assembled Zn//PANI-NixV2O5 (PNV) battery exhibits a specific capacity of up to 470 mAh g−1 at 0.1 A g−1, and retains 89.5 % of its capacity after 1000 cycles at 5 A g−1.

Ternary one-dimensional photonic crystal biosensors for efficient bacteria detection: Role of quantum dots and material combinations

A ternary one-dimensional photonic crystal biosensor was proposed for quick and easy bacterial detection. The Air/(AMB)N/D/(AMB)N/Glass structure is formed by a defect layer between two identical periodic structures filled with samples of normal blood and bacteria-infected blood. Three categories of inorganic, organic, and inorganic/organic hybrid materials were used to make the four combinations of proposed photonic crystal biosensors. Aluminum Gallium Nitride (AlxGa1-xN) quantum dots, Gallium Arsenide (GaAs), silica, and polyaniline polymer have been used in the proposed structures to observe and compare their effects are in the infrared and visible regions. The results indicate that incorporating AlxGa1-xN and GaAs quantum dot layers has increased the sensitivity. These designs have two photonic band gaps with multiple suitable detection modes in infrared and visible regions with an approximately linear behavior. A standard blood sample (TBN) and bacterial samples (TB1 to TB7) were distinguished using the optimal parameters.

Improvement in the performance of indium free dye sensitized solar cell by the use of polyaniline composite

The photovoltaic study of the fabricated dye sensitized solar cells is revealed in this paper. To provide indium free approach, fluorine doped tin oxide (FTO) and aluminium doped zinc oxide (AZO) glass substrate were used as charge collectors for counter electrodes and photoanode respectively. Also, a novel and natural mixed dye was used as sensitizer and mixture of doped polymer (polyaniline with metallic oxides of tin, vanadium and cerium) and iodide-triiodide couple was utilized as electrolyte for the cell. Optical band gap and light absorption performance of dyes were studied by ultraviolet–visible (UV–vis) spectroscopy. Surface morphology and elemental composition of polymer composites was studied using scanning electron microscopic (SEM) with energy dispersive X ray (EDX) analysis. Phase analysis of the composites was determined by X-ray diffraction and thermal behavior with the help of thermogravimetric analysis (TGA). Photovoltaic characteristics (I–V) and induced photon to current efficiency (IPCE) measurements were also investigated. Highest IPCE of 17.7 % was observed when polyaniline was doped with oxide of vanadium. Hence an efficient, green, indium free and novel cell is fabricated by the usage of different charge collector substrate, natural dye sensitizer and quasi solid-state electrolyte.

Towards remarkable corrosion protection by synergizing PANI with plasma-electrolyzed inorganic layer

Notwithstanding the increasing interest in the enhancement of the corrosion properties of active metallic materials, the role of organic corrosion barrier remains insufficiently understood with respect to the formation of structural microdefects in the inorganic layer and the decrease in the corrosion rate. The present work proposed the mechanism by which an organic polymer would improve the barrier properties of the defective TiO2 coating as an inorganic layer and thereby, improve corrosion protection. This protection mechanism enhances the hydrophobicity of the TiO2 surface because of the notable homogeneity of the organic polymer polyaniline (PANI). The adsorption of PANI on the surface of the TiO2 coating was verified using SEM and EDAX. The electrochemical performance was enhanced remarkably because of the integral synergy between TiO2 and PANI in the composite, which could be controlled by adjusting the number of deposition cycles. In addition, the novel protection mechanism of this hybrid layer was based on the counter anions stored within PANI. These were released as active corrosion inhibitors upon the onset of a severe chemical attack on the TiO2 layer or metal substrate. Thus, these composites reduced the diffusion of metal ions and prevented the penetration of corrosive ions, thereby yielding a remarkable corrosion resistance.

Molecular Dynamics Simulation Study on the Structural and Thermodynamic Analysis of Oxidized and Unoxidized Forms of Polyaniline.

The conducting polymer polyaniline (PANI) has shown significant interest for the development of electrified membranes (EMs) with superior antifouling characteristics. However, the blending and doping of PANI with other polymers and nanomaterials highly influence the properties of the membrane surface. PANI exists in two forms: oxidized, known as emeraldine salt (ES), and unoxidized, referred to as emeraldine base (EB). Therefore, understanding the different forms of PANI and the variations between the oxidized and unoxidized forms along the length of the polymer chain is intriguing. In this paper, we present the design of a novel copolymer consisting of EB and ES monomers with varying charge densities and different segmental arrangements. We present various intra- and intermolecular structural properties of the PANI chains using all-atom molecular dynamics (MD) simulations. Herein, we present a detailed conformational free energy analysis to understand the conformational transitions of the PANI chains. Our results show increased radius of gyration (Rg) values with increased charge density. Furthermore, we also present the H-bonding, free energy analysis, reduced density gradient (RDG), and solvent-accessible surface area (SASA) values for the observed conformational transitions of PANI. Therefore, these observations are crucial in understanding the complex behavior of chains for designing target-specific polymeric materials.

Ternary polymeric beads of chitosan-based polyaniline doped iron oxide used for removal of cadmium and lead ions from water: Kinetic, isotherm and mechanism studies

ABSTRACT In this study, the binary polymeric magnetic beads were synthesized successfully by one-pot polymerization of polyaniline (PA) doped magnetic iron oxide nanoparticles (MNPs) followed by chitosan (CTS) cross-linkage. The newly fabricated ternary magnetic beads (CTS@MPA) were applied to enhance the removal of Pb(II) and Cd(II) ions from the aqueous media. The prepared nanocomposite was characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and vibrating sample magnetometry (VSM). Adsorption experiments were carried out under optimum conditions. To evaluate the experimental data, the isotherm and kinetic models were conducted. The behavior of adsorption was assessed, and the coefficient of determination values demonstrated that the adsorption process best fitted the Freundlich model due to high values of R2 (0.957 & 0.981). The maximum adsorption capacity was obtained at 150.82 mg.g−1 and 169.21 mg.g−1 for Pb(II) and Cd(II) ions, respectively. Kinetic studies showed that adsorption follows a pseudo-second-order model (R2 = 0.952 & 0.985). Weber-Morris claims that intraparticle diffusion plays a significant role in the adsorption kinetics. Finally, the thermodynamic study is demonstrated, and the adsorption is endothermic, and the mechanism follows a physisorption pattern.

Biomimetic Ambient‐Pressure‐Dried Aerogels with Oriented Microstructures for Enhanced Electromagnetic Shielding

AbstractOriented aerogels, emerging as a new generation of lightweight electromagnetic interference (EMI) materials, often face complex synthesis processes. While creating an orderly oriented microstructure for EMI aerogels through ambient pressure drying (APD) shows promise, it remains a significant challenge. Here, inspired by the directional grown structure of the plant, a new strategy that employs rapid precursor orientation followed by slow cross‐linking to achieve the APD of directional EMI aerogels is proposed. This approach demonstrates that low‐temperature oriented polymerization of polyaniline enables strong cross‐linking with poly(3,4‐ethylenedioxythiophene) and alginate, forming a robust conductive directional skeleton and mitigating surface tension issues during mild drying. The resulting aerogel features high conductivity (48.84 S m−1), excellent flame retardancy, and impressive compressive strength. Notably, its sturdy frame allows for further enhancement with other functional materials, such as Mxene, through re‐processing and re‐drying. The tree‐branch‐like aerogel achieves a significantly improved EMI shielding effectiveness of 50.3 dB across an ultrawideband range of 8.2–40 GHz. This strategy offers a new idea for the straightforward preparation of functional aerogels with programmability and oriented microstructures using ambient drying.

Characterization and linear / nonlinear optical aspects of polyaniline (PANI) films incorporated with Ethylenediamine for low-cost limiting optical technologies

Polymer composite combined film with Polyaniline (PANI) and Ethylenediamine (EDA) were successfully synthesized via the spin coating technique on a glass substrate followed by different thermal annealing degrees and times. Successful incorporation of EDA into the PANI polymer matrix and the effect of the annealing temperature have been demonstrated by XRD, FTIR, FESEM and TEM. Using UV–Vis optical spectroscopy, we determine the absorption coefficient, band edge, and Urbach energy. The effects of different annealing temperatures and times on linear/nonlinear optical characteristics were investigated. The band gap of EDA-doped PANI films is reduced with the different thermal annealing from 3.43 eV to 3.19 eV, while the Urbach tail of the 100 °C/4h film which is 0.492 eV was decreased to 0.469 eV for 150 °C/1h sample. However, the absorbance and optical conductivity were both increased. Besides, the optical limiting effect assesses their potential to mitigate intense light. It was found from the study that for green wavelength 100 °C/4h film decreases the input power by 16.5 % whereas the 150 °C/1h sample shows superior limiting behavior of 99.96 %. It has been found that thermal annealing of the EDA-doped PANI films enhances the synthetic composite's optical characteristics, making the 150 °C/1h sample of EDA-doped PANI films appropriate for utilization in both energy applications and optoelectronics.

An environmentally sustainable ultrasonic-assisted exfoliation approach to graphene and its nanocompositing with polyaniline for supercapacitor applications

In the present work, a green high-yielding method for the preparation of graphene is introduced via ultrasonic-assisted liquid phase exfoliation (LPE) of graphite in a green solvent medium, since the common preparation method of graphene via graphite oxide is hazardous. A high concentration of 3.2 mg/ml graphene is achieved here in a comparatively short duration of 3 h ultrasonication. By using a mixed solvents strategy (acetophenone and isopropyl alcohol, 1:19 V/V), surface energy requirements needed for the exfoliation of graphite are satisfied here with acetophenone, where isopropyl alcohol further facilitated the exfoliation via non-conventional CH-π and OH-π interactions. Turbostratic graphene in high-yield (16 %) in a simple means of ultrasonic assisted LPE is the added attraction of the present procedure. The less-defective structure of graphene, its few-layered turbostratic nature, and edge functionalization of the sheets are evident from the material characterization via Raman spectroscopy, XRD, TEM-SAED, and XPS analyses. Here, we report a combination of the attractive conducting polymer polyaniline (PANI) with the as-prepared graphene for supercapacitor applications, where the PANI/graphene nanocomposites with different aniline concentrations (PANI1.125/G, PANI4.5/G, and PANI9/G) have been prepared via in-situ polymerization of aniline in the graphene dispersion. The structure and morphology of the nanocomposites are investigated using different characterization techniques which revealed that the molecular structure of the PANI is retained in the nanocomposites even with a strong interaction with graphene. FESEM and TEM images revealed the good coverage of graphene sheets with PANI that limit the volume change of PANI during the repeated charge-discharge processes. Electrochemical studies showed that PANI4.5/G has the highest specific capacitance of 126.16 mF/cm2 at a current density of 1 mA/cm2, resulting from the perfect combination of the pseudocapacitance behavior of the PANI along with the electrical double layer capacitance of graphene. A symmetric supercapacitor device is also fabricated with PANI4.5/G, which showed the highest areal capacitance of 116.38 mF/cm2 similar to that with three-electrode studies and also good cycling stability with 87 % capacitance retention in the specific capacitance after 6000 cycles. It also exhibited an energy density of 16 µWh/cm2 (0.29 Wh/kg) and a power density of 3.99 mW/cm2 (72.72 W/kg).

Evidence of Cooperative Effects for the Fe(phen)2(NCS)2 Spin Crossover Molecular Complex in Polyaniline Plus Iron Magnetite.

The spin crossover complex Fe(phen)2(NCS)2 and its composite, Fe(phen)2(NCS)2, combined with the conducting polymer polyaniline (PANI) plus varying concentrations of iron magnetite (Fe3O4) nanoparticles were studied. A cooperative effect is evident from the hysteresis width in the plot of magnetic susceptibility multiplied by temperature versus temperature (χmT versus T) for Fe(phen)2(NCS)2 with PANI plus varying concentrations of Fe3O4 nanoparticles. The hysteresis width in the composites vary no more than 2 K with respect to the pristine Fe(phen)2(NCS)2 spin crossover crystallites despite the fact that there exists a high degree of miscibility of the Fe(phen)2(NCS)2 spin crossover complex with the PANI. The Fe3O4 nanoparticles in the Fe(phen)2(NCS)2 plus PANI composite tend to agglomerate at higher concentrations regardless of the spin state of Fe(phen)2(NCS)2. Of note is that the Fe3O4 nanoparticles are shown to be antiferromagnetically coupled with the Fe(phen)2(NCS)2 when Fe(phen)2(NCS)2 is in the high spin state.

Periodate activation with polyaniline-derived carbon for bisphenol A degradation: Insight into the roles of nitrogen dopants and non-radical species formation

Periodate-based advanced oxidation processes (PI-AOPs) activated by carbon catalysts have shown promising application prospects in the removal of emerging contaminants. Herein, a series of N-doped carbon catalysts (NC) were prepared by in-situ pyrolysis of N-containing polymers (polyaniline) to unveil the potential mechanism of N dopants on PI activation. The optimized sample NC700 showed a satisfying degradation performance, achieving 100 % removal of bisphenol A (BPA) at a concentration of 10 mg/L within 90 min in the presence of 0.1 mM PI. The impacts of various N types on PI activation were systematically investigated by dynamic fitting and density functional theory computations. These analyses highlighted the crucial role of graphitic N configuration on carbon surface, which exhibited the highest adsorption energy and a positive correlation with the normalized degradation efficiency. The chemical quenching experiments and electrochemical experiments confirmed that the BPA oxidation mechanism was primarily mediated electron transfer by [NC-PI]* complex, with singlet oxygen (1O2) /superoxide radicals (O2•–) playing a supplementary role. In situ ATR-SERAS measurement strengthened the understanding of PI activation by carbon catalyst based on electron transfer pathway. Owing to the non-radical oxidation mechanism, the NC/PI system had a broad pH adaptability and great anti-interference ability against typical wastewater components. This study provides mechanistic insights into the carbon-driven PI activation process for wastewater treatment, advancing the practical application of PI-AOPs.

Sodium alginate supramolecular nanofibers in synergy with surface crack engineering to prepare tough and highly sensitive hydrogels

Soft and wet hydrogels often struggle to achieve both toughness and high sensitivity simultaneously, limiting their usefulness in flexible devices. To tackle this challenge, we devised a strategy that combines supramolecular sodium alginate nanofibers, utilizing Zr4+ as physical crosslinkers, with surface crack engineering via the micro-phase separation of polyaniline, to create a physically and chemically dual crosslinked polyacrylamide (PAM)/sodium alginate (SA)/polyaniline (PANI) hydrogel with exceptional toughness and high sensitivity. Owing to the supramolecular sodium alginate nanofibers, the dual crosslinked hydrogel exhibited a tensile strength of 0.391 MPa, an elongation at break of 568.9 %, and a toughness of 1.020 MJ/m3. The in-situ polymerized polyaniline layer, confined within the dense network, introduced micro-cracks onto the hydrogel surface, resulting in a high gauge factor of 11.4 for the fabricated hydrogel. Furthermore, integrating this hydrogel into a triboelectric nanogenerator transformed it into self-powered sensors capable of detecting external forces and generating various signals without power supply. These findings suggest that the developed hydrogel held great potential in diverse fields, including human motion detection, human-machine interaction, and wearable electronic devices.

Synergetic studies on the thermochemical activation and polyaniline integration on the adsorption properties of natural coal for chlorpyrifos pesticide: steric and energetic studies

Three types of synthetic coal-derived adsorbents were characterized as potential enhanced structurers during the removal of chlorpyrifos pesticide. The raw coal (CA) was activated into porous graphitic carbon (AC), and both CA and AC were blended with polyaniline polymers (PANI/CA and PANI/AC) forming two advanced composites. The adsorption performances of the modified structures in comparison with CA were evaluated based on both the steric and energetic parameters of the applied advanced isotherm model (the monolayer model of one energy). The uptake performances reflected higher capacities for the PANI hybridized form (235.8 mg/g (PANI/CA) and 309.75 mg/g (PANI/AC) as compared to AC (156.9 mg/g) and raw coal (135.8 mg/g). This signifies the impact of activation step and PANI blending on the surface and textural properties of coal. The steric investigation determined the saturation of the coal surface with extra active sites after the activation step (Nm(AC) = 62.05 mg/g) and the PANI integration (Nm(PANI/CA) = 113.5 mg/g and Nm(PANI/AC) = 169.7 mg/g) as compared to raw coal (Nm(CA) = 39.6 mg/g). This illustrated the reported uptake efficiencies of the modified samples, which can be attributed to the enhancement in the surface area and the incorporation of additional chemical groups. The results also reflect that each site can be loaded with 3–4 molecules of chlorpyrifos, which are arranged vertically and adsorbed by multi-molecular mechanisms. The energetic studies (< 40 kJ/mol) suggested the physical uptake of pesticide molecules by dipole bonding and hydrogen bonding processes. The thermodynamic functions donate the exothermic properties of 47reactions that occur spontaneously.

WO3 Nanoparticle/Biomass Derived N‐Doped Activated Carbon Decorated with Polyaniline Nanofibers Ternary Nanocomposite for High‐Performance Symmetric and Asymmetric Supercapacitor

AbstractSupercapacitors have captured the curiosity of researchers due to their extremely high energy storage capacity. Hybrid supercapacitors deliver high specific capacitance values compared to the exciting (electrical double layer capacitor) EDLC and pseudocapacitors. This work presents a simple and scalable synthetic method to design a hybrid ternary composite as electrode material. In this work, the combination of EDLC‐type behaviour material, i. e., sustainable biomass‐derived Nitrogen‐doped activated carbon (NAC) and pseudocapacitive behaviour electrode materials, i. e., metal oxides (tungsten oxide) and conductive polymer (polyaniline) are selected to achieve a high gravimetric capacity. The PANi/WO3/NAC (PWNAC) ternary composite is tested for symmetric and asymmetric supercapacitor (ASC). In a symmetric capacitor, PWNAC acts as both the positive and negative electrode, whereas in ASC, PWNAC acts as the positive electrode and NAC as the negative electrode. It is observed that the ASC shows a better capacitance value than symmetric. ASC operates at a potential range of 1.4 V in 1 M H2SO4 aqueous electrolyte, shows a maximum capacitance of 608.2 F/g at 0.5 A/g, and has long capacitance retention of 98.32 % of its initial capacitance after 2000 charge‐discharge cycles.

Non-enzymatic detection of 17β-estradiol in real samples using PANI@CeO2 nanocomposite

Herein, we developed a non-enzymatic biosensing platform using polyaniline (PANI) polymer matrix grafted with CeO2. The one-pot synthesized nanocomposite has been used for the detection of 17β-estradiol (E2). The homogeneous distribution of CeO2 onto the PANI matrix leads to an increase in surface area, conductivity, and effectiveness of the synthesized nanocomposite PANI@CeO2. The PANI@CeO2 nanocomposite was characterized using structural and morphological techniques. Further, the electrode fabrication was performed electrophoretically by depositing the PANI@CeO2 nanocomposite onto the ITO electrode. The PANI@CeO2/ITO showed enhanced electrochemical behavior as compared to PANI/ITO. Detection of E2 was carried out using the differential pulse voltametric technique (DPV). Linearity has been observed through the detection range of 1 µM–100 µM with LOD = 2.15 µM. The developed biosensor has been found to be stable and selective towards E2. It has been successfully utilized for the detection of E2 in real samples like tap water and human urine samples. Thus, this research encourages its use for more applications in clinical diagnosis and biomedical sciences.

Synergetic studies on the nitrogen functionalization and polyaniline hybridization on the uptake performances of acephate pesticides by raw coal: Steric and energetic studies

Three forms of modified coal-based adsorbents were developed and characterized as potential enhanced structurers during the removal of acephate pesticide. The raw coal (CA) was oxidized by nitric acid, forming nitrogen functionalized coal (N.CA), and both CA and N.CA were hybridized with polyaniline polymers (PANI/CA and PANI/N.CA). The adsorption performances of the modified structures in comparison with CA were evaluated based on both the steric and energetic parameters of the applied advanced isotherm model (the monolayer model of one energy). The uptake performances reflected higher capacities for the PANI hybridized form (261.9 mg/g (PANI/CA) and 316.6 mg/g (PANI/N.CA) as compared to N.CA (232.3 mg/g) and raw coal (201.2 mg/g). This signifies the impact of nitrogen functionalization and PANI hybridization on the surface properties of coal. The steric investigation determined the saturation of the coal surface with extra active sites after the nitric acid treatment (Nm (N.CA) = 103.5 mg/g) and the PANI hybridization (Nm (PANI/CA) = 119.07 mg/g and Nm (PANI/N.CA) = 146.4 mg/g) as compared to raw coal (Nm (CA) = 81.9 mg/g). This illustrated the reported uptake efficiencies of the modified samples, which can be attributed to the enhancement in the surface area (5.4 m2/g (CA), 18.3 m2/g (N.CA), 27.7 m2/g (PANI/CA), and 36.2 m2/g (PANI/N.CA)) and the incorporation of additional chemical groups (NO, C-N, and N-H). The results also reflect that each site can be loaded with three molecules of acephate, which are arranged vertically and adsorbed by multi-molecular mechanisms. The energetic studies (<40 kJ/mol) suggested the physical uptake of pesticide molecules by dipole bonding and hydrogen bonding processes. The thermodynamic functions reflect the exothermic properties of reactions that occur spontaneously.

Strategic Design of Conductive Biopolymer Surface Coatings for Sensing and Remediation Applications

Advancement in the utility of conductive polysaccharide-based (i.e., agar, alginate, pectin, cellulose) composite materials for charge transfer applications requires effective surface functionalization and dopant matching to overcome limitations in electron transfer in these dielectric materials. A promising approach is the design of a biomimetic nanocomposite material, coupled with Fe-carboxyl coordination chemistry to photoinitiate the radical polymerization of polyaniline (PANI) in a uniform manner throughout a templated polymer matrix. Results have shown the feasibility of establishing a responsive carbon-based sensor, capable of modulating charge transfer performance in the presence of differing dopants (i.e., hydrochloric acid, sulfuric acid, polyelectrolyte). The aim of this work is to expand upon previous findings by unraveling the dopant-specific charge transport mechanisms as they relate to the polarizability and mobility of the dopant. Additionally, a network-level understanding of how changing the identity of the polymer backbone and the conductive polymer (i.e., aniline, pyrrole, thiophene) alters the charge transfer efficiency and overall stability of the conductive matrix. Current-voltage (I-V) sweeps reveal that these n-doped conductive polymer nanocomposites show enhanced current flow and reduced internal resistance compared to non-functionalized controls. Lastly, once the network reached an equilibrated state, the addition of a model contaminant (mucin) showed a decrease in the potential; however, upon an applied voltage, the contaminant was removed, and the system recovered to its original state. Alternatively, the network was also evaluated for the remediation of model pollutants. Results show that upon an applied voltage in simulated textile wastewater, there was a 10% degradation of methylene blue within 1 hour. Thus, the backbone/dopant/conducting polymer relationship is critical to achieving optimal performance with various applications.