AFM Analysis Research Articles

Synthesis of a novel next-generation positively charged polymer and its in-situ grafting into thin film composite membranes to enhance the performance for desalination

High efficiency of the polyamide membranes can be achieved by rationally tailoring the active layer, which empowers the membrane with better anti-fouling characteristics, high flux, and separation efficiencies. Herein, a next-generation anti-fouling positively charged copolymer of diallyldimethylammonium chloride (DADMAC) and N1, N1-diallyldodecane-1,12-diammonium chloride (DADAC) was synthesized and thoroughly characterized by TGA, FTIR, proton (1H) and the carbon (13C) NMR. The synthesized poly(DADMAC-co-DADAC), after conversion to poly(DADMAC-co-DADA) having free NH2 group, was in-Situ grafted while forming the active layer due to its rationally designed anchoring points of NH2 group. The in-Situ grafting resulted in a cross-linked polyamide active layer containing positively charged brushes of poly (DADMAC-co-DADA) at regular intervals. The AFM analysis has shown that the polyamide layer's surface roughness increased with the poly-(DADMAC-co-DADA) grafting concentration, which positively impacts the membranes' flux. When exposed to the water, the grafted poly-(DADMAC-co-DADA) expanded and spread a positively quaternary ammonium network on the membrane surface, effectively repelling the cations. The introduced membrane has shown high performance compared to the pristine polyamide membrane. The functionalized membranes have displayed a 3.5 times flux for 2000 ppm of NaCl while maintaining a good rejection at 93.1%. The anti-fouling behavior of the membranes was evaluated against the model positively charged CTAB (cetyltrimethylammonium bromide) foulants (2000 ppm). Poly- (DADMAC-co-DADA) grafted membranes have shown a high anti-fouling tendency. After 600 min (10 h) of continuous operation, the flux declined less than 15%, whereas the pristine polyamide membrane lost 99%. The poly-(DADMAC-co-DADA) grafted membranes recovered more than 93% of their maximum flux. Thus, the in-Situ grafting of positively charged polymer is a possible opportunity to develop the next generation of high-performance polyamide membranes.

Anti-inflammatory effects of tellurium dioxide -niobium pentoxide nanocomposite coatings on titanium implants

Replacement of joints is a significant subspecialty of bone replacement surgery that calls for mechanically robust and biologically compatible, or biocompatible, implants. In this study, incorporating tellurium dioxide with niobium pentoxide is an effective method to impart the coatings with antibacterial properties by a thermal decomposition method on titanium substrate. The developed coatings were treated for alkaline treatment and was subjected for in vitro study in 1.5 Kukubo’s simulated body fluid to enhance biogrowth and adhesion strength. The physico-chemical and surface characterization revealed the presence of nanocomposite coatings with the deposition apatite on the surface of titanium metal strip was confirmed by XRD, FTIR, EIS, CV, SEM and AFM analysis studies. The electrochemical experiments revealed that the developed coatings had high adhesion strength and great biomimetic growth characteristics. The antibacterial test was used to evaluate the antibacterial properties of tellurium dioxide-niobium pentoxide coatings respectively. Antibacterial assays determined that treatment with nanocomposite coating at concentrations of 0.62 to 5 µg/mL induced a decay in the growth of both Gram-negative and Gram-positive bacteria. The highest zone of inhibition was observed for Staphylococcus aureus and Escherichia coli respectively. These properties show that for the first time, tellurium dioxide-niobium pentoxide nanocomposite coating can be used as a powerful inflammatory agent. In summary, this study provided an alternative method to prepare the nanocomposite coating with low temperature, low-cost technique can promote the physico-chemical interaction to effectively fabricate bioactivity with antibacterial and anti-inflammatory ability for bioimplants.

Numerical Calculation of Magnetic Field Enhancement and Impact of Surface Defects on Premature Entry of Magnetic Field in Thin Nb Films for SRF Cavities

In this work, we have investigated two series of Nb/Cu samples deposited by HiPIMS technique, and differing in Nb deposition conditions, Nb film thickness and Cu substrate polishing techniques. All the films were additionally irradiated by Nd:YAG laser to smooth their surfaces. The impact of the magnetic field enhancement at the surface defects on the premature start of magnetic field penetration into the superconducting film was studied, combining experiments and numerical calculations. Compared to previous study, improved numerical calculations by using the Finite Element Method (FEM) served to calculate the maximum field enhancement factor β <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> , reflecting impact of the most crucial surface defects found in the samples. Magnetization measurements at 4.2 K in DC magnetic field, oriented parallel to the film, were employed to determine the start of the field penetration <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">en</sub> . The SEM and AFM analyses served to investigate the Nb surface morphology. In some samples, deviations from the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">en</sub> (β <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> ) dependence were observed. It was found that the magnetic field penetration could start from the Nb/Cu interface rather than from the free Nb surface due to visibly better quality of the free Nb surface observed by SEM analysis, and that could lead to the deterioration of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">en</sub> (β <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> ) dependence.

Cathodic arc deposition of nanocrystalline titanium nitride thin film on fluorine doped tin oxide coated glass substrate: Crystal structural, microstructural, mechanical, optical and electrical properties

The nanocrystalline titanium nitride (TiN) films were deposited on fluorine doped tin oxide (FTO) coated glass substrates for the first time by cathodic arc deposition. The crystalline phase and orientation, growth morphology, surface roughness, hardness, scratch adhesion, electrical resistivity, optical absorption and bandgap of the TiN films were investigated. The GI-XRD confirmed the formation of cubic TiN and crystallographic orientation growth. The 2150 nm thick TiN film showed (111) orientation due to columnar growth patterns, while the 650 nm TiN film formed with the (200) orientation. The grain size of TiN films was 50–200 nm by FESEM and AFM analyses, and it was formed as elongated nanocrystals of 65–125 nm width and 120–250 nm lengths. The microhardness of the 650, 1000 and 2150 nm TiN thin films was measured to be 836, 943 and 1281 HV0.05 respectively. The scratch adhesion test demonstrated a good adhesive strength up to a critical load of 10 N and beyond the delamination occurred. The electrical resistivity of TiN film found to vary with thickness, the 650 nm TiN film showed a low resistivity of 16 × 10-6 Ω cm, which is comparable with the electrical resistivity of platinum and magnetron sputtered TiN film. The UV-Vis-NIR diffused reflectance spectroscopic studies of the TiN thin film showed a sharp absorption at 448 nm due to plasmon absorption and Tauc plot showed direct band gap of 2.1 eV. The results demonstrated that cathodic arc deposited nanocrystalline TiN thin film deposited on FTO glass substrate can be used as counter electrode for dye sensitized solar cell (DSSC) applications.

Highly efficient color mixing system for the fine-tuning of white light–PLEDs using blue and red poly-chromophores

The fine tuning of color and white light emission was achieved from the simple blending of two different types of polychromophores. The π-conjugated polymeric chromophores (blue and red) were synthesized and characterized for white light polymer emitting diode (WPLED) applications. The binary luminescent materials, Blue polymeric chromophore (BPy) and (Red polymeric chromophore (RPy), were obtained from the respective monomers via a standard Suzuki coupling reaction. The tuning of colors and white light emission were attained directly mixing of two polymeric chromophores (blue, red) in different ratio. The prepared polymer materials were confirmed using standard tehniques such as, Fourier transform infrared (FT-IR) and 13C and 1H-nuclear magnetic resonance (NMR) spectroscopy, while the gel-permeation chromatography result revealed the polymeric properties of the materials. The polymeric materials surfaces morphologies were analysed throught the FE-SEM and AFM analysis. The TGA (Thermogravymetric analysis) used to study the thermal property of the two prepared polymeric materials. The UV–visible and fluorescence spectrophotometry was applied to examine the optical features of the materials. The BPy and RPy polymers shows absorption peaks at 375 nm and 426 nm, respectively. The obatined emission peaks of BPy and RPy are at 426 nm and 603 nm, respectively. These results show that BPy and RPy belong to the blue and red emissive categories, and the white light emission was obtained with the mixing ratio of BPy(80%)-RPy(20%). The bandgap of these materials was calculated by cyclic voltammetry, and the theoretical bandgap of the materials was calculated by density functional theory analysis. Finely structured devices were fabricated, and the efficiencies of the BPy, RPy, and BPy-RPy were analyzed to assess the luminance productivity of the materials. In summary, this paper proposes a simple method to achieve white color emission by mixing polymeric chromophores at different ratios.

Effect of CVI SiC interphase on tensile properties of SiC fibers with different surfaces

The microstructure, and tensile properties of as-received SiC fiber and SiC coated fiber with different surfaces were investigated. The surface microstructure and composition of the fibers were analyzed through the AFM, SEM, Raman, AES, and TEM analysis. The SiC fibers were or not desized firstly, and then BN interphase or SiC interphase was deposited by CVI process. The tensile properties of the fibers before and after the deposition of the SiC interphase were evaluated, and the influence of the surface composition of SiC fibers on its tensile properties was studied. The results showed that the fiber surface is rich in free carbon and oxygen. The fibers without interphase showed the best tensile properties than those with coated fibers. After depositing SiC interphase, the tensile strength of SiC monofilament without sizing agent and BN interphase reduced mostly.

Effects of functionalization and silane modification of hexagonal boron nitride on thermal/mechanical/morphological properties of silicon rubber nanocomposite

Hexagonal boron nitride (h-BN) nanoparticles could induce interesting properties to silicone rubber (SR) but, the weak filler-matrix interfacial interaction causes agglomeration of the nanoparticles and declines the performance of the nanocomposite. In this work, h-BN nanoparticles were surface modified using vinyltrimethoxysilane (VTMS) at different concentrations. Before silane modification, h-BN nanoparticles were hydroxylated using 5 molar sodium hydroxide. The nanoparticles were characterized to assess success of silane grafting. The pure and modified h-BN nanoparticles were applied at 1, 3 and 5 wt% to HTV silicon rubber (SR). The curing, thermal, mechanical and morphological properties and hydrophobicity of the nanocomposites were evaluated. The morphology of the SR nanocomposites was characterized using AFM and FE-SEM analysis. It was found that silane grafting on the h-BN nanoparticles improves crosslink density but declines curing rate index (CRI) of the SR nanocomposite (at 5 wt% loading content) by 0.7 (dN m) and 3.5%, respectively. It also increased water contact angle of the nanocomposites from 97.5° to 107°. The improved nanoparticle-rubber interfacial interactions caused better dispersion of h-BN nanoparticles in SR matrix (at 5 wt%) that enhanced the elongation at break, modulus at 300% and Tg of the SR nanocomposites.

Improved corrosion protection of a NiTi implant by an electrodeposited HAp-Nb2O5 composite layer

The mechanical and biological characteristics of NiTi alloy provide opportunities in biomedical fields ranging from orthopedics to intravascular stents. However, Ni ion release when the alloy is exposed to corrosive body fluid can lead to long-term health-related concerns. Improved surface engineering via the application of biological layers on the NiTi can contribute to higher corrosion resistance. HAp-based layers were cathodically deposited from an aqueous electrolyte containing calcium nitrate, ammonium dihydrogen phosphate, and concentrations of suspended Nb2O5 particles from 0 to 1 g/L under pulsed current conditions. Surface morphology, topography, and surface chemistry of the electroplated layers were characterized by FESEM, AFM, and FTIR analysis, respectively. The corrosion behavior of the bare and coated samples in Ringer's solution was evaluated by EIS and potentiodynamic polarization; the corroded surfaces were imaged by FESEM. A more compact and smoother surface was formed in the presence of particulate Nb2O5 inclusions. The composite coating showed excellent anti-corrosion properties, increasing the polarization resistance of pure HAp films by >10 times. FESEM imaging of corroded surfaces showed the partial detachment of plate-like HAp crystals from the surface of the coated NiTi in contrast to the pitting of the bare NiTi surface. The surface modification of NiTi by electrodeposited HAp-Nb2O5 composite coatings might play an important role in the future use of NiTi in clinical applications.

Synthesis and characterization of Silver nanoparticles: A review

In the current century, nanotechnology has gained great interest due to its ability to modify the size of metals to the nanoscale, which dramatically changes the physical, chemical, and biological characteristics of metals relative to their bulk counterparts. The approaches used to create nanoparticles (NPs) are physical, و chemical and وbiological. The shortcomings in physical and chemical synthesis approaches, such as the generation of toxic by-products, and energy consume as they require high temperature, pressure, power and lethal chemicals, contributed to an increased interest in biological synthesis by plants. Scientists have created a new filed called as "green nanotechnology" by fusing the idea of sustainability with nanotechnology. By substituting plant-based materials, it aims to reduce the amount of chemicals used in the manufacture of nanoparticles. Silver nanoparticles (AgNPs) attract the most attention due to their great stability and low chemical reactivity in comparison to other metals. The present review describes the fabrication of nanoparticles (NPs) via chemical and physical methods, as well as the use of plants, bacteria, and fungi. The current review also discusses certain analytical methods used to examine AgNPs, including UV-Vis spectroscopy, FT-IR, SEM, TEM, AFM, XRD, DLS, and zeta potential analysis

Synthesis and characterization of Hypsizygus ulmarius extract mediated silver nanoparticles (AgNPs) and test their potentiality on antimicrobial and anticancer effects

The prime aim of this research is to discover new, eco-friendly approaches to reducing agents for manufacturing silver nanoparticles (AgNPs) from fresh fruiting bodies of the edible mushroom Hypsizygus ulmarius (Hu). The confirmation of Hu-mediated AgNPs has been characterized by UV visible spectroscopy, XRD, FTIR, SEM with EDX, HRTEM, AFM, PSA, Zeta poetical and GCMS analysis. The absorption peak of Hu-AgNPs at 430 nm has been confirmed by UV–visible spectroscopy analysis. The findings of the particle size study show that AgNPs have a size distribution with an average of 20 nm. The Zeta potential of NPs reveals a significant build-up of negative charges on their surface. The additional hydrate layers that occurred at the surface of AgNPs are shown in the HR-TEM morphology images. The antibacterial activity results showed that Hu-AgNPs were highly effective against both bacterial pathogens, with gram-positive (+) and gram-negative (−) pathogens having a moderate inhibition effect on K. pneumoniae (5.3 ± 0.3 mm), E. coli (5.3 ± 0.1), and S. aureus (5.2 ± 0.3 mm). Hu-AgNPs (IC50 of 50.78 μg/mL) were found to have dose-dependent cytotoxic action against human lung cancer cell lines (A549). Inhibited cell viability by up to 64.31% after 24 h of treatment. To the best of our knowledge, this is the hand information on the myco-synthesis of AgNPs from the H. ulmarius mushroom extract and the results suggest that it can an excellent source for developing a multipurpose and eco-friendly nano product in future.

Morphological studies of polypyrrole/silver nanocomposites

Polypyrrole/silver (PPy/Ag) nanocomposites of weight percentages (0.1%, 0.5%, 3%, 5% and 7% wt.) were synthesized via a chemical oxidation method. The AFM analysis is performed to study the surface roughness, morphology and size distribution of PPy particles and PPy-Ag nanocomposites. The results indicated that as the concentration of Ag in the nanocomposite increases, the roughness increases. The size of nanoparticles was also evaluated and found to be in the range of 15 nm to 125 nm. The PPy/Ag nanocomposites exhibited an effectiveness against Gram-negative Escherichia coli showing an inhibition zone of 4mm and displayed poor efficacy against Gram-positive Staphylococcus aureus. Based on given adequate antibacterial characteristics of PPy/Ag nanocomposites, it can be identified as a promising material in biomedical applications.

Interwoven of γ-MnO2 and V2O5 nanostructures with polyindole grafted reduced graphene oxide nano-platform for high-efficient supercapacitors: A collaborated insight of experimental and surface morphological studies

The continuous evolution toward high-yield electronic devices with green and mechanical robust properties offers an emerging demand for polymeric nanocomposite electrodes. Herein, an efficient in-situ electro-synthesized route was pursued in designing novel reduced graphene oxide/polyindole (rGO/PIND) nanocomposite electrodes decorated by γ-MnO2 and V2O5 nanostructures. A nanosecond fiber laser was applied to synthesize V2O5 nanoparticles through laser ablation in liquid (LAL) technique and γ-MnO2 nanostructure was constructed by a solid-state reaction method. The fabricated electrodes were characterized by physical and electrochemical methods. To investigate the effect of the surface morphological features on the electrochemical (EC) performance of nanocomposite electrodes the surface statistical, Areal Autocorrelation Function (AACF), and fractal studies were carried out by using AFM analysis. These studies revealed the presence of nanoparticles results in more compactness and well-developed surface morphology with more roughness and irregularity. The electrochemical study of the design electrodes was performed in three and two-electrode setups. Two asymmetric supercapacitors (ASCs) of rGO//rGO/PIND/V2O5, rGO//rGO/PIND/γ-MnO2 were fabricated and characterized by physical and electrochemical methods. The rGO//rGO/PIND/γ-MnO2 ASSC device provided a superior specific capacitance (CS) of 165F g−1, energy density of 51.5 Wh kg−1, and power density of 3.7 kW kg−1 at 5.0 A g−1 with 95.7% retention of CS after 10,000 cycles and with a broad 1.50 V potential window. Additionally, the rGO/PIND/γ-MnO2//rGO/PIND/γ-MnO2 symmetric supercapacitor (SSC) device exhibited 28.5 Wh kg−1 energy density, and 6.8 kW kg−1 power density at 5.0 A g−1 with 92.8% retention capacitance after 10,000 cycles.

Amikacin-Loaded Chitosan Hydrogel Film Cross-Linked with Folic Acid for Wound Healing Application.

Numerous carbohydrate polymers are frequently used in wound-dressing films because they are highly effective materials for promoting successful wound healing. In this study, we prepared amikacin (AM)-containing hydrogel films through the cross-linking of chitosan (CS) with folic acid along with methacrylic acid (MA), ammonium peroxodisulfate (APS), and methylenebisacrylamide (MBA). In the current studies, an effort has been made to look at the possibilities of these materials in developing new hydrogel film wound dressings meant for a slow release of the antibiotic AM and to enhance the potential for wound healing. Free-radical polymerization was used to generate the hydrogel film, and different concentrations of the CS polymer were used. Measurements were taken of the film thickness, weight fluctuation, folding resistance, moisture content, and moisture uptake. HPLC, FTIR, SEM, DSC, and AFM analyses were some of the different techniques used to confirm that the films were successfully developed. The AM release profile demonstrated regulated release over a period of 24 h in simulated wound media at pH 5.5 and 7.4, with a low initial burst release. The antibacterial activity against gram-negative bacterial strains exhibited substantial effectiveness, with inhibitory zones measuring approximately 20.5 ± 0.1 mm. Additionally, in vitro cytocompatibility assessments demonstrated remarkable cell viability, surpassing 80%, specifically when evaluated against human skin fibroblast (HFF-1) cells. The exciting findings of this study indicate the promising potential for further development and testing of these hydrogel films, offering effective and controlled antibiotic release to enhance the process of wound healing.

The investigation of deposited organic carbon‐silicon films using cyclonic atmospheric pressure plasma polymerization

AbstractBackgroundThe upgrading of atmospheric‐pressure plasma polymerization process, the detailed investigation of atmospheric‐pressure plasma polymerization deposited organic carbon‐silicon film features is essential to obtain the further understandings into the optimizing coating techniques.AimThis investigation demonstrates plasma cyclone deposited film features with adjusting argon gas flow rate and HMDSN monomer flow rate.MethodThis study utilized the plasma cyclone system to polymerize a carbon‐silicon film. In this study, Optical Emission Spectroscopy (OES) was employed as a diagnostic tool to indirectly inspect the chemical composition of the atmospheric‐pressure plasma polymerization's glow discharge by detecting the photo‐emitting species. The Contact Angle Goniometer, ATR‐FTIR, AFM, and XPS were used to measure the surface properties of the films deposited by plasma cyclone.ResultsThe static contact angle results show that most of the deposited films obtain the divergent contact angle values with adjusting argon gas flow rate and HMDSN monomer flow rate. ATR‐FTIR results show that argon gas flow rate and HMDSN monomer flow rate dominate the porosity of plasma cyclone deposited film surface. XPS and AFM analyses also detect the comparable trend of physicochemical characteristics of organic carbon‐silicon film with adjusting argon gas flow rate and HMDSN monomer flow rate. In summary, the organic carbon‐silicon films can be successfully polymerized by plasma cyclone.ConclusionsThe results refer that the organic carbon‐silicon film deposition on vanadium redox flow battery separator surface improved the electrolyte uptake of the cyclonic‐plasma‐coated separators was larger than that of a commercial separator.

Evaluation of covalent and supra-molecular interactions in phosphated galacturonic-glucuronic acid for network structure for use in wound dressings

Keeping in view the wound healing properties of sterculia gum (SG) and ceftriaxone in consideration, in the present work, antibiotic drug encapsulated SG and poly(vinylphosphonic acid) [poly(VPA)] based copolymeric hydrogel wound dressings were designed to enhance the wound healing. Copolymers were characterized by FESEM & EDS, AFM, FTIR, 13C NMR, XRD, TGA and biomedical assay of blood compatibility, mucoadhesion and antioxidant properties. AFM analysis revealed 76.5 nm average roughness and XRD analysis showed sharp peaks at 2θ = 21°. FTIR spectrum of copolymer indicated characteristic peaks at 1116 cm−1 due to stretching vibration of P = O groups of poly(VPA) and twin peaks at 985 and 920 cm−1 due to asymmetric and symmetric vibration of P-O respectively and depicted grafting of phosphated polymers onto gum. The hemolysis test (hemolysis index = 3.40 ± 0.18%) revealed biocompatible nature and the adhesion test demonstrated 84 ± 5.00 mN detachment force which was required to detach the copolymer from the mucosal membrane. Hydrogel dressings absorbed 6.0 ± 5.00 (g/g gel) simulated wound fluid to main the moist wound environment. They were found permeable to O2 and impermeable to microbes and also exhibited antioxidant character. The release profile of ceftriaxone elucidated sustained release of encapsulated ceftriaxone drug with non-Fickian diffusion mechanism and was best fitted in first order kinetic model. Covalent and supra-molecular interactions formed in phosphated galacturonic-glucuronic acid of sterculia gum (SG) were found useful for sustained drug delivery and mucoadhesive properties. These biophysical interactions demonstrated the suitability of antibiotic-encapsulated network structures for wound dressing applications.

Investigation on the precipitate morphology and fraction characterization by atomic force microscopy

Precipitate was typically characterized by the transmission electron microscopy (TEM) or scanning electron microscopy (SEM) to analyze the relationship between material property and precipitate fraction. However, these procedures tend to be are always time consuming because of the complicated sample preparation process involved and the observation course. Particularly, sometime the precipitate can't be highlighted solely from the images easily. In this study, atomic force microscopy (ATM) was performed to characterize the morphology and fraction of the precipitate in this paper. Five kinds of materials were selected and prepared by electropolishing or vibration polishing method to display the precipitates on the sample surface. The experiment results prove that different types of precipitates with higher values for height on a sample surface could be clearly observed by AFM, and the images quality is highly relied upon the surface quality. The precipitate fraction can be calculated using the AFM micrographs and image photo post treated software (IPP). It was turned out that AFM is found suitable for observation almost all kinds of precipitates, and the precipitates can be easily separated from the images. Not only vibration polishing but also electrolytic polishing could offer a smooth surface for observing nanosized precipitates by AFM. A comparison of the fraction result obtained by AFM and precise microchemical analysis proves that the fraction measurement result obtained by AFM is acceptable.

Introducing of leached supercapacitor coin-devices with excellent performance based on tungsten oxide-carbon nanotubes-graphite nanocomposite

In this study, leached graphite coin decorated with tungsten oxide nanoparticles and carbon nanotubes (leached tungsten oxide/carbon nanotubes-graphite coin) with high surface area and excellent mechanical strength is introduced as a novel and low-cost electrode in the supercapacitor application. The leached tungsten oxide/carbon nanotubes-graphite coin was easily fabricated via uniform addition of commercial Zinc-metal powder into the matrix of commercial graphite powder and carbon nanotubes powder, pressing under optimized pressure followed by treatment in H2SO4 solution for leaching out of Zinc from carbon nanotubes-graphite matrix and finally electrodeposition of tungsten oxide nanoparticles onto the previously leached coin. The surface chemistry and structure features of the leached coin were investigated by FTIR, RAMAN, XRD, SEM, TEM, AFM and BET analysis. The leached tungsten oxide/carbon nanotubes-graphite coin had acceptable capacitive characteristic such as negligible ohmic drop and favorite specific capacitance of 3519 mF cm−2 at 2 mA cm−2 in aqueous 1.0 M H2SO4 media. After assembling a symmetric supercapacitor coin-device including leached tungsten oxide/carbon nanotubes-graphite coin in a PVA/H2SO4 gel, the coin-device shows a high specific capacitance of 283 mF cm−2 at the current density of 2.5 mA cm−2.

Analysis of pectin-cellulose interaction in cell wall of lotus rhizome with assistance of ball-milling and galactosidase

The current study sought to depict the structural feature of polysaccharides extracted from Na2CO3 unextractable fraction (LUN) of lotus rhizome using galactosidase with assistance of ball milling. The extracted polysaccharides were a complex of cellulose microfibrils and the RG-I structural domain of pectin, and the top three monosaccharides were glucose, galactose and galactose uronic acid, which allowed to tune the properties of the enzyme-hydrolyzed polysaccharide from LUN after 15 and 45 min of ball milling. The data of XRD revealed that pectin has a masking effect on the diffraction peaks of cellulose components. The removing of the polysaccharides could increase the degree of crystallinity and the pectin-cellulose interaction mainly occured through the galactan side chain was speculated. Textural characterization by SEM exhibited a cross-linked rod-like structure, which is similar to the structure of cellulose microfibrils. The morphological analysis of AFM revealed that L15-P (enzyme-hydrolyzed polysaccharide from LUN after 15 min of ball milling) contained relatively ordered and uniform network structures. Overall, the present study provides an important insight into cell wall of lotus rhizome matrix polysaccharide.

Study on carbonate ester and ether-based electrolytes and hard carbon anodes interfaces for sodium-ion batteries

The hard carbon (HC) is the key anode materials for sodium ion batteries. While the electrolyte and interface from carbonate-based and ether-based electrolytes on the HC has not been deeply analysed. Herein, by combining the theory calculation with experiments analysis of Fourier transform infrared spectroscopy, we successfully construct accurate Na+-solvents models that the oxidation resistance stability of Na+[EC2/EMC/DMC][PF6−] complexes are better than that of Na+[DIGLYME4][CF3SO3−] sheaths. And also, the reduction resistance stability of the ether-based electrolyte is better than that of ester-based electrolyte. It is also demonstrated that the ether-based electrolytes generate dense, thin and fast Na-ions transport SEI on the HC particles at the initial stage of the electrochemical cycle, and the organics fill the gaps between inorganics in carbonated ester-based electrolytes, effectively preventing electrolyte decomposition and permeation in the long cycling process by CV, TEM, EIS, AFM, ToF-SIMS and XPS analysis. It is also found that the ratio of organic to inorganic components in DIGLYME-based electrolyte is greater than in EC/DMC/EMC-based electrolyte after cycling, which may affect the electrochemical performance of cells.

Facile Processing of Unsubstituted π‐Conjugated Aromatic Polymers through Water‐solubilization Using Aromatic Micelles

Abstractπ‐Conjugated aromatic polymers (πCAPs) are central components of functional materials yet suffer from insolubility without multiple covalent substituents on their backbones. We herein disclose a new strategy for the facile processing of unsubstituted heterocyclic πCAPs (i.e., poly(para‐phenylene‐2,6‐benzobisoxazole) and poly(benzimidazobenzo‐phenanthroline)), independent of the polymer length, via non‐covalent encircling with aromatic micelles, composed of bent aromatic amphiphiles, in water. The UV/Visible studies reveal that the efficiencies of the present encircling method are ≈10 to 50‐fold higher than those using conventional amphiphiles under the same conditions. The AFM and SEM analyses of the resultant aqueous polymer composites show that otherwise insoluble πCAPs form fine bundles (e.g., ≈1 nm in thickness) in the tubular aromatic micelles, through efficient π‐stacking interactions. In the same way, pristine poly(para‐phenylene) can be dissolved in water, displaying enhanced fluorescence (10‐fold), relative to the polymer solid. Two types of unsubstituted πCAPs are likewise co‐encircled in water, indicated by UV/Visible analysis. Importantly, aqueous processing of the encircled πCAPs into free‐standing single‐ or multicomponent films with submicrometer thickness is demonstrated through a simple filtration‐annealing protocol.