High Proton Conducting Polymer Blend Electrolytes Based on Chitosan:Dextran with Constant Specific Capacitance and Energy Density

Nanocellulose/wood ash-reinforced starch-chitosan hydrogel composites for soil conditioning and their impact on pea plant growth

Hydrogels are 3-dimensional polymer networks capable of absorbing a large amount of water. Natural polymeric hydrogels are biodegradable, non-toxic and biocompatible. They can effectively retain nutrients for the plant and can be used as soil conditioners. This study uses a chemical cross-linking technique to synthesize starch and chitosan-based hydrogel using citric acid as a cross-linker. Additionally, hydrogel composites were developed by incorporating wood ash, nano-cellulose, and NPK (nitrogen-phosphorus-potassium) fertilizer as fillers to enhance their properties. The formulated hydrogel/hydrogel composite samples were characterized by FTIR spectroscopy, SEM analysis, X-ray diffraction and thermo-gravimetric analysis. The experiment results showed the chemical cross-linking among the polymeric chain and the semi-crystalline nature of the hydrogel/hydrogel composite samples. The swelling capacity of the hydrogel/hydrogel composite samples was 200-420% (in distilled water) and 104-220% (in saline medium) and demonstrated biodegradability within 110 days. The NPK reinforced hydrogel composite showed an excellent effect on the growth of pea plants (leaves count = 37, stem height = 20.2 cm), and could be effectively used as soil conditioners for agricultural applications. Considering the ability of hydrogel composites to reduce irrigation needs, enhance nutrient retention, and improve crop production, these novel hydrogel composites present an economically viable solution for sustainable agricultural practices.

Graphene oxide reinforced biopolymeric (chitosan) hydrogels for controlled cephradine release

In the current study, chitosan, poly (N-vinyl-2-pyrolidone) and polyamidoamine based hydrogels were prepared by Solution Casting Method using different quantity of graphene oxide (GO) for controlled cephradine (CPD) release. The hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, thermal analysis, scanning electron microscope and atomic force microscopy. FTIR results endorsed the presence of particular functionalities and developed interfaces in hydrogels. The thermal stability was directly proportional to the amount of GO. Antibacterial activity was investigated against gram-negative bacteria resultantly; CAD-2 exhibited maximum bactericidal activity against Escherichia coli and Psuedomonas aeruginosa. In addition, in-vitro biodegradation was examined in phosphate buffer saline solution and proteinase K for 21 and 07 days respectively. The maximum swelling was exhibited by CAD-133777 % in distilled water that was governed by quasi-Fickian diffusion. The swelling volumes were inversely proportional to the amount of GO. In the same way, pH sensitive CPD release was detected by UV visible spectrophotometer that followed zero order and Higuchi models. However, in 4 h, 89.4 % and 83.7 % of CPD was released in PBS and SIF solution correspondingly. Therefore, the chitosan-based biocompatible and biodegradable hydrogel platforms offered substantial potential for the controlled CPD release in medico-biological applications.

The Study of Ion Transport Parameters in MC-Based Electrolyte Membranes Using EIS and Their Applications for EDLC Devices

A solution cast technique was utilized to create a plasticized biopolymer-based electrolyte system. The system was prepared from methylcellulose (MC) polymer as the hosting material and potassium iodide (KI) salt as the ionic source. The electrolyte produced with sufficient conductivity was evaluated in an electrochemical double-layer capacitor (EDLC). Electrolyte systems’ electrical, structural, and electrochemical properties have been examined using various electrochemical and FTIR spectroscopic techniques. From the electrochemical impedance spectroscopy (EIS), a maximum ionic conductivity of 5.14 × 10⁻⁴ S cm⁻¹ for the system with 50% plasticizer was recorded. From the EEC modeling, the ion transport parameters were evaluated. The extent of interaction between the components of the prepared electrolyte was investigated using Fourier transformed infrared spectroscopy (FTIR). For the electrolyte system (MC-KI-glycerol), the t_ion and electrochemical windows were 0.964 and 2.2 V, respectively. Another electrochemical property of electrolytes is transference number measurement (TNM), in which the ion predominantly responsibility was examined in an attempt to track the transport mechanism. The non-Faradaic nature of charge storing was proved from the absence of a redox peak in the cyclic voltammetry profile (CV). Several decisive parameters have been specified, such as specific capacitance (C_s), coulombic efficiency (η), energy density (E_d), and power density (P_d) at the first cycle, which were 68 F g⁻¹, 67%, 7.88 Wh kg⁻¹, and 1360 Wh kg⁻¹, respectively. Ultimately, during the 400th cycle, the series resistance ESR varied from 70 to 310 ohms.

Evaluation of an Injectable Hydrogel Based on Hyaluronic Acid-chitosan/β-glycerophosphate-loaded Mesenchymal Stem Cells in Enhancing the Therapeutic Efficacy of Myocardial Infarction

Myocardial infarction (MI), which is due to cardiac dysfunction, results in morbidity and mortality. Moreover, the cellular activity of transplanted mesenchymal stem cells (MSCs)generally limits their therapeutic efficacy in the treatment of MI. Here, inject able hyaluronic acid-chitosan/β-glycerophosphate (HA-CS/β-GP) hydrogel-loaded MSCs were prepared, after which their effects on the treatment of MI were investigated. The synthesized HA-CS/β-GP hydrogels exhibited swelling ratio (SR), an in vitro degradation value, and a gelatin time of 82.19 ± 4.1, 88.18% ± 2.4%, and 9 s, respectively. Further, rheological studies revealed that the elastic modulus of the HA-CS/β-GP hydrogels was ≥230 Pa, exhibiting large elastic to viscous modulus ratio, which indicated their mechanical strength. Furthermore, the in vitro 3T3 cell and MSC culture studies confirmed the good biocompatibility of the HA-CS and HA-CS/β-GP hydrogels. The implantation of the synthesized hydrogels in the mouse MI model considerably improved the therapeutic effect of the MSCs (enhanced cardiac function, reduced cardiomyocyte apoptosis, and increased vascularization) for the first time. The innovative synergistic strategy of combining injectable HA-CS and HA-CS/β-GP hydro gels with MSCs might be suitable for the effective treatment of cardiac morbidity due to MIs. This article is protected by copyright. All rights reserved.

Bio-Based Plasticized PVA Based Polymer Blend Electrolytes for Energy Storage EDLC Devices: Ion Transport Parameters and Electrochemical Properties

This report shows a simple solution cast methodology to prepare plasticized polyvinyl alcohol (PVA)/methylcellulose (MC)-ammonium iodide (NH₄I) electrolyte at room temperature. The maximum conducting membrane has a conductivity of 3.21 × 10^-3 S/cm. It is shown that the number density, mobility and diffusion coefficient of ions are enhanced by increasing the glycerol. A number of electric and electrochemical properties of the electrolyte-impedance, dielectric properties, transference numbers, potential window, energy density, specific capacitance (C_s) and power density-were determined. From the determined electric and electrochemical properties, it is shown that PVA: MC-NH₄I proton conducting polymer electrolyte (PE) is adequate for utilization in energy storage device (ESD). The decrease of charge transfer resistance with increasing plasticizer was observed from Bode plot. The analysis of dielectric properties has indicated that the plasticizer is a novel approach to increase the number of charge carriers. The electron and ion transference numbers were found. From the linear sweep voltammetry (LSV) response, the breakdown voltage of the electrolyte is determined. From Galvanostatic charge-discharge (GCD) measurement, the calculated C_s values are found to drop with increasing the number of cycles. The increment of internal resistance is shown by equivalent series resistance (ESR) plot. The energy and power density were studied over 250 cycles that results to the value of 5.38-3.59 Wh/kg and 757.58-347.22 W/kg, respectively.

Structural, Electrical and Electrochemical Properties of Glycerolized Biopolymers Based on Chitosan (CS): Methylcellulose (MC) for Energy Storage Application

In this work, a pair of biopolymer materials has been used to prepare high ion-conducting electrolytes for energy storage application (ESA). The chitosan:methylcellulose (CS:MC) blend was selected as a host for the ammonium thiocyanate NH₄SCN dopant salt. Three different concentrations of glycerol was successfully incorporated as a plasticizer into the CS–MC–NH₄SCN electrolyte system. The structural, electrical, and ion transport properties were investigated. The highest conductivity of 2.29 × 10⁻⁴ S cm⁻¹ is recorded for the electrolyte incorporated 42 wt.% of plasticizer. The complexation and interaction of polymer electrolyte components are studied using the FTIR spectra. The deconvolution (DVN) of FTIR peaks as a sensitive method was used to calculate ion transport parameters. The percentage of free ions is found to influence the transport parameters of number density (n), ionic mobility (µ), and diffusion coefficient (D). All electrolytes in this work obey the non-Debye behavior. The highest conductivity electrolyte exhibits the dominancy of ions, where the ionic transference number, t_ion value of (0.976) is near to infinity with a voltage of breakdown of 2.11 V. The fabricated electrochemical double-layer capacitor (EDLC) achieves the highest specific capacitance, C_s of 98.08 F/g at 10 mV/s by using the cyclic voltammetry (CV) technique.

Convenient conversion of hazardous nitrobenzene derivatives to aniline analogues by Ag nanoparticles, stabilized on a naturally magnetic pumice/chitosan substrate

Herein, silver nanoparticles (Ag NPs), as an effective catalyst for the reduction process of nitrobenzene derivatives to non-hazardous and useful aniline derivatives, are conveniently synthesized on an inherently magnetic substrate. For this purpose, an efficient combination of volcanic pumice (VP), which is an extremely porous igneous rock, and a chitosan (CTS) polymeric network is prepared and suitably used for the stabilization of the Ag NPs. High magnetic properties of the fabricated Ag@VP/CTS composite, which have been confirmed via vibrating-sample magnetometer (VSM) analysis, are the first and foremost advantage of the introduced catalytic system since it gives us the opportunity to easily separate the particles and perform purification processes. Briefly, higher yields were obtained in the reduction reactions of nitrobenzenes (NBs) under very mild conditions in a short reaction time. Also, along with the natural biocompatible ingredients (VP and CTS) in the structure, excellent recyclability has been observed for the fabricated Ag@VP/CTS catalytic system, which convinces us to do scaling-up and suggests the presented system can be used for industrial applications.

Saeed S, Brza MA, Abdulwahid RT, Hamsan MH, M. Abdullah R, Kadir MFZ, Muzakir SK. Investigation of Ion Transport Parameters and Electrochemical Performance of Plasticized Biocompatible Chitosan-Based Proton Conducting Polymer Composite Electrolytes

In this study, biopolymer composite electrolytes based on chitosan:ammonium iodide:Zn(II)-complex plasticized with glycerol were successfully prepared using the solution casting technique. Various electrical and electrochemical parameters of the biopolymer composite electrolytes' films were evaluated prior to device application. The highest conducting plasticized membrane was found to have a conductivity of 1.17 × 10-4 S/cm. It is shown that the number density, mobility, and diffusion coefficient of cations and anions fractions are increased with the glycerol amount. Field emission scanning electron microscope and Fourier transform infrared spectroscopy techniques are used to study the morphology and structure of the films. The non-Debye type of relaxation process was confirmed from the peak appearance of the dielectric relaxation study. The obtained transference number of ions (cations and anions) and electrons for the highest conducting sample were identified to be 0.98 and 0.02, respectively. Linear sweep voltammetry shows that the electrochemical stability of the highest conducting plasticized system is 1.37 V. The cyclic voltammetry response displayed no redox reaction peaks over its entire potential range. It was discovered that the addition of Zn(II)-complex and glycerol plasticizer improved the electric double-layer capacitor device performances. Numerous crucial parameters of the electric double-layer capacitor device were obtained from the charge-discharge profile. The prepared electric double-layer capacitor device showed that the initial values of specific capacitance, equivalence series resistance, energy density, and power density are 36 F/g, 177 Ω, 4.1 Wh/kg, and 480 W/kg, respectively.

Synthesis of Porous Proton Ion Conducting Solid Polymer Blend Electrolytes Based on PVA: CS Polymers: Structural, Morphological and Electrochemical Properties

In this study, porous cationic hydrogen (H+) conducting polymer blend electrolytes with an amorphous structure were prepared using a casting technique. Poly(vinyl alcohol) (PVA), chitosan (CS), and NH4SCN were used as raw materials. The peak broadening and drop in intensity of the X-ray diffraction (XRD) pattern of the electrolyte systems established the growth of the amorphous phase. The porous structure is associated with the amorphous nature, which was visualized through the field-emission scanning electron microscope (FESEM) images. The enhancement of DC ionic conductivity with increasing salt content was observed up to 40 wt.% of the added salt. The dielectric and electric modulus results were helpful in understanding the ionic conductivity behavior. The transfer number measurement (TNM) technique was used to determine the ion (tion) and electron (telec) transference numbers. The high electrochemical stability up to 2.25 V was recorded using the linear sweep voltammetry (LSV) technique.

Blending and Characteristics of Electrochemical Double-Layer Capacitor Device Assembled from Plasticized Proton Ion Conducting Chitosan:Dextran:NH4PF6 Polymer Electrolytes

This research paper investigates the electrochemical performance of chitosan (CS): dextran (DX) polymer-blend electrolytes (PBEs), which have been developed successfully with the incorporation of ammonium hexafluorophosphate (NH₄PF₆). X-ray diffraction (XRD) analysis indicates that the plasticized electrolyte system with the highest value of direct current (DC) ionic conductivity is the most amorphous system. The glycerol addition increased the amorphous phase and improved the ionic dissociation, which contributed to the enhancement of the fabricated device’s performance. Transference number analysis (TNM) has shown that the charge transport process is mainly by ions rather than electrons, as t_ion = 0.957. The CS:DX:NH₄PF₆ system was found to decompose as the voltage goes beyond 1.5 V. Linear sweep voltammetry (LSV) revealed that the potential window for the most plasticized system is 1.5 V. The fabricated electrochemical double-layer capacitor (EDLC) was analyzed with cyclic voltammetry (CV) and charge-discharge analysis. The results from CV verify that the EDLC in this work holds the characteristics of a capacitor. The imperative parameters of the fabricated EDLC such as specific capacitance and internal resistance were found to be 102.9 F/g and 30 Ω, respectively. The energy stored and power delivered by the EDLC were 11.6 Wh/kg and 2741.2 W/kg, respectively.

Hadi J, Dannoun EMA, Abdulwahid RT, R. Saeed S, Shahab Marf A, Karim WO, Kadir MF. The Study of Plasticized Amorphous Biopolymer Blend Electrolytes Based on Polyvinyl Alcohol (PVA): Chitosan with High Ion Conductivity for Energy Storage Electrical Double-Layer Capacitors (EDLC) Device Application

In this study, plasticized films of polyvinyl alcohol (PVA): chitosan (CS) based electrolyte impregnated with ammonium thiocyanate (NH4SCN) were successfully prepared using a solution-casting technique. The structural features of the electrolyte films were investigated through the X-ray diffraction (XRD) pattern. The enrichment of the amorphous phase with increasing glycerol concentration was confirmed by observing broad humps. The electrical impedance spectroscopy (EIS) portrays the improvement of ionic conductivity from 10-5 S/cm to 10-3 S/cm upon the addition of plasticizer. The electrolytes incorporated with 28 wt.% and 42 wt.% of glycerol were observed to be mainly ionic conductor as the ionic transference number measurement (TNM) was found to be 0.97 and 0.989, respectively. The linear sweep voltammetry (LSV) investigation indicates that the maximum conducting sample is stable up to 2 V. An electrolyte with the highest conductivity was used to make an energy storage electrical double-layer capacitor (EDLC) device. The cyclic voltammetry (CV) plot depicts no distinguishable peaks in the polarization curve, which means no redox reaction has occurred at the electrode/electrolyte interface. The fabricated EDLC displays the initial specific capacitance, equivalent series resistance, energy density, and power density of 35.5 F/g, 65 Ω, 4.9 Wh/kg, and 399 W/kg, respectively.

Nofal M, San S, Abdulwahid RT, Raza Saeed S, Brza MA, Kadir MFZ, Mohammed SJ, Al-Zangana S. From Cellulose, Shrimp and Crab Shells to Energy Storage EDLC Cells: The Study of Structural and Electrochemical Properties of Proton Conducting Chitosan-Based Biopolymer Blend Electrolytes

In this study, solid polymer blend electrolytes (SPBEs) based on chitosan (CS) and methylcellulose (MC) incorporated with different concentrations of ammonium fluoride (NH₄F) salt were synthesized using a solution cast technique. Both Fourier transformation infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results confirmed a strong interaction and dispersion of the amorphous region within the CS:MC system in the presence of NH₄F. To gain better insights into the electrical properties of the samples, the results of electrochemical impedance spectroscopy (EIS) were analyzed by electrical equivalent circuit (EEC) modeling. The highest conductivity of 2.96 × 10⁻³ S cm⁻¹ was recorded for the sample incorporated with 40 wt.% of NH₄F. Through transference number measurement (TNM) analysis, the fraction of ions was specified. The electrochemical stability of the electrolyte sample was found to be up to 2.3 V via the linear sweep voltammetry (LSV) study. The value of specific capacitance was determined to be around 58.3 F/g. The stability test showed that the electrical double layer capacitor (EDLC) system can be recharged and discharged for up to 100 cycles with an average specific capacitance of 64.1 F/g. The synthesized EDLC cell was found to exhibit high efficiency (90%). In the 1st cycle, the values of internal resistance, energy density and power density of the EDLC cell were determined to be 65 Ω, 9.3 Wh/kg and 1282 W/kg, respectively.

Metal Complex as a Novel Approach to Enhance the Amorphous Phase and Improve the EDLC Performance of Plasticized Proton Conducting Chitosan-Based Polymer Electrolyte

This work indicates that glycerolized chitosan-NH₄F polymer electrolytes incorporated with zinc metal complexes are crucial for EDLC application. The ionic conductivity of the plasticized system was improved drastically from 9.52 × 10⁻⁴ S/cm to 1.71 × 10⁻³ S/cm with the addition of a zinc metal complex. The XRD results demonstrated that the amorphous phase was enhanced for the system containing the zinc metal complex. The transference number of ions (t_ion) and electrons (t_e) were measured for two of the highest conducting electrolyte systems. It confirmed that the ions were the dominant charge carriers in both systems as t_ion values for CSNHG4 and CSNHG5 electrolytes were 0.976 and 0.966, respectively. From the examination of LSV, zinc improved the electrolyte electrochemical stability to 2.25 V. The achieved specific capacitance from the CV plot reveals the role of the metal complex on storage properties. The charge–discharge profile was obtained for the system incorporated with the metal complex. The obtained specific capacitance ranged from 69.7 to 77.6 F/g. The energy and power densities became stable from 7.8 to 8.5 Wh/kg and 1041.7 to 248.2 W/kg, respectively, as the EDLC finalized the cycles.

Nofal M, Karim WO, Brevik I, Brza MA, Abdulwahid RT, Al-Zangana S, Kadir MFZ. Structural, Impedance and Electrochemical Characteristics of Electrical Double Layer Capacitor Devices Based on Chitosan: Dextran Biopolymer Blend Electrolytes

This report presents the preparation and characterizations of solid biopolymer blend electrolyte films of chitosan as cationic polysaccharide and anionic dextran (CS: Dextran) doped with ammonium iodide (NH4I) to be utilized as electrolyte and electrode separator in electrical double-layer capacitor (EDLC) devices. FTIR and XRD techniques were used to study the structural behavior of the films. From the FTIR band analysis, shifting and broadening of the bands were observed with increasing salt concentration. The XRD analysis indicates amorphousness of the blended electrolyte samples whereby the peaks underwent broadening. The analysis of the impedance spectra emphasized that incorporation of 40 wt.% of NH4I salt into polymer electrolyte exhibited a relatively high conductivity (5.16 × 10-3 S/cm). The transference number measurement (TNM) confirmed that ion (tion = 0.928) is the main charge carriers in the conduction process. The linear sweep voltammetry (LSV) revealed the extent of durability of the relatively high conducting film which was 1.8 V. The mechanism of charge storage within the fabricated EDLC has been explained to be fully capacitive behavior with no redox peaks appearance in the cyclic voltammogram (CV). From this findings, four important parameters of the EDLC; specific capacitance, equivalent series resistance, energy density and power density were calculated as 67.5 F/g, 160 ohm, 7.59 Wh/kg and 520.8 W/kg, respectively.

Electrochemical Characteristics of Glycerolized PEO-Based Polymer Electrolytes

In this article, poly(ethylene oxide)-based polymer electrolyte films doped with ammonium iodide (NH4I) and plasticized with glycerol were provided by a solution casting method. In the unplasticized system, the maximum ionic conductivity of 3.96 × 10-5 S cm-1 was achieved by the electrolyte comprised of 70 wt. % PEO:30 wt. % NH4I. The conductivity was further enhanced up to (1.77×10-4 S cm-1) for the plasticized system when 10 wt. % glycerol was added to the highest conducting unplasticized one at ambient temperature. The films were characterized by various techniques to evaluate their electrochemical performance. The results of impedance spectroscopy revealed that bulk resistance (Rb) considerably decreased for the highest plasticized polymer electrolyte. The dielectric properties and electric modulus parameters were studied in detail. The LSV analysis verified that the plasticized system can be used in energy storage devices with electrochemical stability up to 1.09 V and the TNM data elucidated that the ions were the main charge carrier. The values of the ion transference number (tion) and electron transfer number (tel) were calculated. The nonappearance of any redox peaks in the cyclic voltammograms indicated that the chemical reaction had not occurred at the electrode/electrolyte interface.

Ionic Conductivity and Structure of Chitosan Films Modified with Lactic Acid-Choline Chloride NADES

The natural deep eutectic solvent (NADES) based on choline chloride (ChCl) and lactic acid (LA) was used for the preparation of chitosan (CS) films by the solution casting method. The content of NADES in films was from 0 to 82 wt%. The impact of NADES on the morphology and crystalline structure of films was investigated using scanning electron microscopy as well as wide-angle and small-angle X-ray scattering. The experimental results allow to propose CS chains swelling in NADES. FTIR spectroscopy confirms the interactions between CS and NADES components via the formation of hydrogen and ion bonds. The thermal properties of the composite films were studied by simultaneous thermogravimetric and differential thermal analysis. Thermomechanical analysis demonstrated appearance of two transitions at temperatures between -23 and -5 °C and 54-102 °C depending on NADES content. It was found that electrical conductivity of film with 82 wt% of NADES reaches 1.7 mS/cm. The influence of the composition and structure of films on the charge carriers concentration and their mobility is discussed.

Ion Transport Study in CS: POZ Based Polymer Membrane Electrolytes Using Trukhan Model

In this work, analysis of ion transport parameters of polymer blend electrolytes incorporated with magnesium trifluoromethanesulfonate (Mg(CF₃SO₃)₂) was carried out by employing the Trukhan model. A solution cast technique was used to obtain the polymer blend electrolytes composed of chitosan (CS) and poly (2-ethyl-2-oxazoline) (POZ). From X-ray diffraction (XRD) patterns, improvement in amorphous phase for the blend samples has been observed in comparison to the pure state of CS. From impedance plot, bulk resistance (R_b) was found to decrease with increasing temperature. Based on direct current (DC) conductivity (σ_dc) patterns, considerations on the ion transport models of Arrhenius and Vogel–Tammann–Fulcher (VTF) were given. Analysis of the dielectric properties was carried out at different temperatures and the obtained results were linked to the ion transport mechanism. It is demonstrated in the real part of electrical modulus that chitosan-salt systems are extremely capacitive. The asymmetric peak of the imaginary part (M_i) of electric modulus indicated that there is non-Debye type of relaxation for ions. From frequency dependence of dielectric loss (ε″) and the imaginary part (M_i) of electric modulus, suitable coupling among polymer segmental and ionic motions was identified. Two techniques were used to analyze the viscoelastic relaxation dynamic of ions. The Trukhan model was used to determine the diffusion coefficient (D) by using the frequency related to peak frequencies and loss tangent maximum heights (tanδ_max). The Einstein–Nernst equation was applied to determine the carrier number density (n) and mobility. The ion transport parameters, such as D, n and mobility (μ), at room temperature, were found to be 4 × 10⁻⁵ cm²/s, 3.4 × 10¹⁵ cm⁻³, and 1.2 × 10⁻⁴ cm²/Vs, respectively. Finally, it was shown that an increase in temperature can also cause these parameters to increase.