Strong Thermal Stability Research Articles

Thermal Properties of Ultrasound-Extracted Okra Mucilage

Utilizing chemical and physicochemical techniques, the mucilage part of okra was extracted with the use of ultrasound, and the polysaccharide extract’s structural and thermal characteristics were assessed. Analysis of the extraction yield revealed that there was no discernible impact of time and that the yield increased with a decreasing okra to distilled water ratio (mean 8%). Differential scanning calorimetry was employed to determine the phase change enthalpy by examining the glass transition temperature and enthalpy. The glass transition temperatures of the samples were found to be about 50 °C and the melting temperatures were in the range of 166–170 °C for varied solid/solvent ratios (1:10, 1:25, 1:30, and 1:50) and extraction durations of 5 and 30 min. Using thermogravimetry (TG) and differential thermogravimetry (DTG) techniques, it was discovered that the okra polysaccharides were thermally stable with considerable weight loss above 240 °C. For the purpose of illuminating the bonds of the polysaccharides, FTIR analysis was used to characterize the polysaccharides obtained by the varying extraction times and rates of solid/solvent. This analysis provides detailed information about the composition of the extracts. It was found that the molecular structure of the mucilage from okra was unaffected by the varying ratios and times. The study’s findings indicated that the use of ultrasound could be a promising approach for extracting polysaccharides that possess strong thermal stability, making them suitable for use in various industrial applications. The study noted that variations in ultrasound application time and solid/solvent ratios did not appear to impact the thermal stability of the extracted polysaccharides. The important parameters for the extraction conditions such as the time and low amount of sample used are preferred for applications. The findings obtained indicate that ultrasonic extraction application at a 1/50 solid/solvent ratio for 5 min is statistically significant in terms of thermal properties and yield. These findings could have important implications for the energy costs associated with the industrial use of ultrasound extraction.

High-temperature and stress response behavior of femtosecond laser pulses inscribed eccentric fiber Bragg gratings

Eccentric fiber Bragg grating (EFBG) is inscribed in standard communication single-mode fiber using femtosecond laser pulses, and the temperature and strain sensing characteristics are experimentally demonstrated and analyzed. The EFBG exhibits strong thermal stability and good robustness in high-temperature measurement up to 1000 °C, and undergoes different thermal sensitivities during Bragg peak and the strong resonance coupled cladding spectral comb. The temperature sensitivity linearly increases with respect to the effective index of the resonant modes. Such a situation also occurs in axial strain measurement. These characteristics are of high interest for multiparametric sensing at high temperatures.

Aluminum copper bimetallic metal organic gels/sodium alginate beads for efficient adsorption of ciprofloxacin and methylene blue: Adsorption isotherm, kinetic and mechanism studies

In this research, a new aluminum-copper bimetallic organic gel was prepared by solvothermal method. It is hoped that the special structure and properties of this new material can be used to remove ciprofloxacin (CIP) and methylene blue (MB) from water to deal with environmental pollution problems. Their morphology and structure were characterized by XRD, FT-IR, XPS, SEM, BET, TGA and zeta potential. It is proved that they have sufficient active sites, large specific surface area (270.5 m2/g), hierarchical porous structure, and strong thermal stability. These properties contribute to their efficient removal of pollutants. Compared with other adsorbents, MOG-4 in this study showed good pollutant removal rate, wide pH adaptability, good anti-interference ability and excellent reuse rate. The maximum adsorption capacity of MOG-4 for CIP and MB was 458.72 mg/ g and 381.68 mg/ g respectively. The adsorption process followed the second-order kinetic model and Freundlich isotherm. More importantly, we constructed MOG-4 @SA beads by immobilizing MOG-4 in sodium alginate (SA) matrix, which not only overcame the shortcomings of difficult recovery and easy agglomeration of powder MOG-4, but also enhanced its adsorption capacity. Seven cycles show that the reuse rate of MOG-4 @SA is more than 84%. The adsorption mechanism involves hydrogen bonding, electrostatic interaction, π-π interaction, hydrophilic/hydrophobic interaction and pore filling. MOG-4 @SA beads adsorbent overcomes the shortcomings of traditional powder adsorbent, which is easy to lose, easy to aggregate and difficult to recover, and broadens the range of use of powder adsorbent and sodium alginate. Therefore, MOG-4 @SA has the advantages of good adsorption performance, high reuse rate, wide range of adaptation, strong anti-interference ability, and is expected to become a promising adsorbent.

Development of a toxin-free competitive immunoassay for aflatoxin M1 based on a nanobody as surrogate calibrator

The toxic standards were indispensable in the identification of small molecule mycotoxins, and the quantities used could pose significant harm to operators and cause secondary environmental contamination. The theory of anti-idiotypic antibodies (AIds) provided an effective way to solve this problem. An anti-idiotypic nanobody named VHH C4 with high specificity and strong thermal stability was used as a surrogate standard, and its recognition mechanism was investigated. A non-toxic enzyme-linked immunoassay (ELISA) was built using VHH C4 as a surrogate standard to detect aflatoxin M1 (AFM1) in milk and dairy products. The detection limit (LOD) of the competitive ELISA was 0.035 ng/mL, with a linear range of 0.045–0.329 ng/mL. The recovery of spiked samples (milk, yogurt, and milk powder) ranged from 84.8% to 92.2%. Compared with the results detected by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) in real samples, the ELISA using VHH C4 as a surrogate standard showed a convincing result. And LOD met the standard limit for AFM1 in dairy products in most countries and organizations. Besides, anti-idiotypic nanobodies solved the problems of polyclonal AIds with large batch inspection differences and cumbersome production processes. In immunoassay systems, VHH C4 had the opportunity to replace the highly toxic and expensive AFM1 standard.

Synergetic Effect of the Iridium Complex for Morphology Optimization in Efficient and Thermally Stable Polymer Solar Cells

Active layer morphology is one of the crucial factors for achieving excellent device performance in polymer solar cells. Recently, solid additives have drawn great attention due to their great potential in morphology control, but a detailed explanation about the working mechanism of solid additive systems is still lacking. In this work, we provided an iridium complex-based solid additive (Ir-OH) to control the morphology and crystallinity of the photoactive layer by utilizing the synergetic effect of dual additives 1-chloronaphthalene and Ir-OH. The morphology of the devices with dual additives exhibited appropriate phase separation and domain size, which provided more continuous pathways for charge transport and also exhibited condensed π–π stacking and fine molecular ordering of photoactive materials, resulting in enhanced charge collection probability. Consequently, the treatment of dual additives exhibited enhanced power conversion efficiency (PCE) with enhanced exciton dissociation, charge collection, and reduced bimolecular recombination. In addition, we found that the device with dual additives exhibited strong thermal stability under a constant heat treatment at 130 °C, and the device performance retained 65% during 24 h, showing an improved PCE of 13.89%. We expected that the favorable morphology of active materials in metal complexes can suppress thermal degradation and lead to improved device performance.

Fast Response GaN Nanoscale Air Channel Diodes with Highly Stable 10 mA Output Current toward Wafer-Scale Fabrication.

Nanoscale air channel transistors (NACTs) have received significant attention due to their remarkable high-frequency performance and high switching speed, which is enabled by the ballistic transport of electrons in sub-100nm air channels. Despite these advantages, NACTs are still limited by low currents and instability compared to solid-state devices. GaN, with its low electron affinity, strong thermal and chemical stability, and high breakdown electric field, presents an appealing candidate as a field emission material. Here, a vertical GaN nanoscale air channel diode (NACD) with a 50nm air channel is reported, fabricated by low-cost IC-compatible manufacturing technologies on a 2-inch sapphire wafer. The device boasts a record field emission current of 11mA at 10V in the air and exhibits outstanding stability during cyclic, long-term, and pulsed voltage testing. Additionally, it displays fast switching characteristics and good repeatability with a response time of fewer than 10ns. Moreover, the temperature-dependent performance of the device can guide the design of GaN NACTs for applications in extreme conditions. The research holds great promise for large current NACTs and will speed up their practical implementation.

Structural & thermal study of Sb14Se(86-x)Sn(x) chalcogenide glassy system

The structural and thermal analyses of Sb14Se(86-x)Sn(x) (x = 3 and × = 6) glassy system generated by the usual melt-quenching approach are presented in this study. Using the differential scanning calorimeter (DSC) technology, the crystallisation mechanism of the produced glass samples were investigated. With increasing Sn content there is increase in glass transition temperature Tg. The less difference in melting temperature and crystallisation temperature makes prepared glasses suitable for memory switching devices. At room temperature the infrared transmission spectra of Sb14Se(86-x)Sn(x) (x = 0, 3, 6, 9, 12 and 15) chalchogenide glasses were acquired in the 2000–2500 cm−1 spectral range. With Sn addition, far IR spectra are shifted towards the high frequency side and some new bonds appear. Because it was evident that Se atoms were being replaced by Sn atoms, a corresponding rise in the production of Sn-Sn bonds and a subsequent fall in Se-Se bonds were seen. The glasses produced in this manner exhibit improved glass forming capability and strong thermal stability. There was good agreement between experimental data and theoretical estimations of bond energy, relative likelihood of bond formation, and wave number. [copyright information to be updated in production process]

Manipulation of Magnetization Switching by Ultrafast Spin‐Polarized Hot‐Electron Transport in Synthetic Antiferromagnet

AbstractUncovering the physical mechanisms that govern ultrafast charge and spin dynamics is becoming indispensable both at the fundamental level and to develop future spin‐based electronics. Recently it has been shown that femtosecond pulsed‐laser excitation of magnetic thin films produces intense and ultrafast spin‐polarized hot electrons, thus attracting a lot of attention. While spin‐polarized hot electrons are known to play a pivotal role in the ultrafast laser‐induced demagnetization, their effect on magnetization switching remains an open issue. This study uncovers the effect of spin‐polarized hot electrons generated by laser excitation on magnetization switching in a Co/Pt based perpendicular magnetic anisotropy‐based synthetic antiferromagnet (p‐SAF) using the time‐resolved magneto‐optical Kerr effect. It has been found that, at low pump fluence, the equivalent magnetic field generated by the hot‐electron spin current plays a dominant role in assisting the magnetization switching of the lower layer in the antiferromagnetic configuration, while the strong thermal stability of the Ruderman Kittel Kasuya Yosida exchange interaction inhibits the further weakening of the switching field at high pump fluence. This study provides a viable way to control the magnetization switching of the antiferromagnetically exchange‐coupled systems for spintronic applications with ultrafast control of the information operation.

Effects of graphene, alumina, and their hybrid on dynamic mechanical behavior of epoxy-based nanocomposites

Graphene has excellent mechanical and thermal properties, while alumina has inexpensive and strong thermal stability, making it ideal for electronic packaging applications. The current work examines the effects of modest loadings of reduced graphene oxide (rGO), alumina (Ala), and their hybrids on the dynamic mechanical characteristics and thermal transitions of epoxy-based nanocomposites. The rGO was made using a modified Hummers’ method. Alumina nanoparticles were used as received. Various epoxy nanocomposite samples with 1 wt% of rGO, 1 wt% of Ala, and 0.5 wt% each of rGO and Ala were created. Then, Raman spectroscopy, XRD, FTIR, XPS, TEM, AFM, and SEM were used to analyze the fillers and their hybrid and epoxy-based nanocomposites. Dynamic mechanical analysis was used to examine the hybrid epoxy-based nanocomposites’ dynamic mechanical behavior. It has been demonstrated that different epoxy nanocomposites with 1 wt% Ala and 1 wt% rGO have higher elastic moduli than those with 0.5 wt% rGO and 0.5 wt% Ala. The rGO-Ala hybrid nanocomposites, on the other hand, exhibit moderate damping and glass transition temperatures. The reason for that may be because Ala filler increases the contact area between the rGO sheets and serves as a bridge between the two fillers, decreasing the resistance to deformation. This may enhance the possibility that these stress concentrations will weaken the composites.

H3PO4-Induced Nano-Li3PO4 Pre-reduction Layer to Address Instability between the Nb-Doped Li7La3Zr2O12 Electrolyte and Metallic Li Anode

Solid-state batteries based on a metallic Li anode and nonflammable solid electrolytes (SEs) are anticipated to achieve high energy and power densities with absolute safety. In particular, cubic garnet-type Nb-doped Li7La3Zr2O12 (Nb-LLZO) SEs possess superior ionic conductivity, are feasible to prepare under ambient conditions, have strong thermal stability, and are of low cost. However, the interfacial compatibility with Li metal and Li dendrite hazards still hinder the applications of Nb-LLZO. Herein, a quick and efficient solution was applied to address this issue, generating a nano-Li3PO4 pre-reduction layer from the reaction of H3PO4 with the ion-exchanged passivation layer (Li2CO3/LiOH) on the surface of Nb-LLZO. A lithiophilic, electrically insulating interlayer is in situ created when the Li3PO4 modified layer interacts with molten Li, successfully preventing the reduction of Nb5+. The interlayer, which mostly consists of Li3P and Li3PO4, also has a high shear modulus and relatively high Li+ conductivity, which effectively inhibit the growth of Li dendrites. The Li|Li3PO4|Nb-LLZO|Li3PO4|Li symmetric cells stably cycled for over 5000 h at 0.05 mA cm-2 and over 1000 h at a high rate of 0.15 mA cm-2 without any short circuits. The LiFePO4 and S/C hybrid solid-state batteries using the modified Nb-LLZO electrolyte also demonstrated good electrochemical performances, confirming the practical application of this interfacial engineering in various solid-state battery systems. This work offers an efficient solution to the instability issue between the Nb-LLZO SE and metallic Li anode.

Hyperbranched organic-inorganic co-modification improves the strength, dimensional stability, and thermal stability of poplar wood

High-strength, dimensionally-stable, moisture-absorbing, and heat-insulating materials are critical for ensuring the safety of building structures and human comfort. As a natural moisture-adjusting and heat-insulating material, wood is widely used in buildings, but its low strength and flammability pose safety hazards. This paper reports a simple method to construct an organic-inorganic hyperbranched structure in poplar wood (W Si-Al-EP ). The bending and compressive strength of W Si-Al-EP reached 103.50 MPa and 80.41 MPa, respectively. This composite wood material exhibited high strength and stable performance, and it also improved the shortcomings of traditional inorganic-modified materials such as unstable sizes and the loss of modifiers. Moreover, the material did not burn in a long-term high-temperature flame, indicating its heat and combustion resistance, and showing that it can be used in wooden building structures. • A method for preparing organic-inorganic hyperbranched structure in wood (W Al-Si-EP ). • W Al-Si-EP has high strength and good dimensional stability. • W Al-Si-EP has strong thermal stability and flame resistance.

Studies on the effect of additives concentrations on synthesis and characterization of furan-lignin foams

Bio-based foams are growing and promising materials to replace petroleum-based foams because of their beneficial qualities including their affordability, outstanding fire resistance, high thermal insulation performance, eco-friendliness and the bio-sourced origin of the feedstock components. This study produced rigid bio-based foams using chemicals derived from plants, primarily from furfuryl alcohol and polyol derived from lignin. Lignin-based polyol and furfuryl alcohol were used to produce furan-lignin foams, which are free of formaldehyde and ozone damaging substances. Seven different furan-lignin foams were produced by substituting the toxic formaldehyde with a more eco-friendly glyoxal as a hardener while using diethyl ether and bentonite as blowing agent and filler respectively. Effects of these reagents on the quality of foams produced were assessed by varying their contents in the formulations. The properties of the produced bio-based foams such as compressive resistance, water absorption capacity, density and moisture content were evaluated. Further product characterizations: elemental composition, thermo-gravimetric analysis, Fourier transforms infrared spectroscopy and Scanning electron microscopy were carried out on the foams. The reaction leading to foam production was spontaneous at room temperature with an acid catalyst. Results showed that the concentrations of the blowing agent, hardener and filler, all had effects on the quality of the bio-based foams produced. Scanning electron microscopy results showed that the foams possessed closed cell morphologies, a rigid foam characteristic for good thermal and acoustic performance but modest water absorption, with cell widths of 10–200 μm, having high densities and strong compressive strengths as inherent characteristics. The results of the characterization indicated that the foams may be used as a thermal barrier or a support in construction and packaging applications because they had strong thermal stability, high compressive strengths, and a modest capacity to absorb water.

Recyclable mesalamine-functionalized magnetic nanoparticles (mesalamine/GPTMS@SiO2@Fe3O4) for tandem Knoevenagel-Michael cyclocondensation: grinding technique for the synthesis of biologically active 2-amino-4H-benzo[b]pyran derivatives.

In the present study, mesalamine-functionalized on magnetic nanoparticles (mesalamine/GPTMS@SiO2@Fe3O4) is fabricated as an efficient and magnetically recoverable nanocatalyst. The as-prepared nanocatalyst was successfully synthesized in three steps using a convenient and low-cost method via modification of the surface of Fe3O4 nanoparticles with silica and GPTMS, respectively, to afford GPTMS@SiO2@Fe3O4. Finally, treatment with mesalamine as a powerful antioxidant generates the final nanocatalyst. Then, its structure was characterized by FT-IR, SEM, TEM, EDX, XRD, BET, VSM, and TGA techniques. The average size was found to be approximately 38 nm using TEM analysis and the average crystallite size was found to be approximately 27.02 nm using XRD analysis. In particular, the synthesized nanocatalyst exhibited strong thermal stability up to 400 °C and high magnetization properties. The activity of the synthesized nanocatalyst was evaluated in the tandem Knoevenagel-Michael cyclocondensation of various aromatic aldehydes, dimedone and malononitrile under a dry grinding method at room temperature to provide biologically active 2-amino-4H-benzo[b]pyran derivatives products in a short time with good yields. The presented procedure offers several advantages including gram-scale synthesis, good green chemistry metrics (GCM), easy fabrication of the catalyst, atom economy (AE), no use of column chromatography, and avoiding the generation of toxic materials. Furthermore, the nanocatalyst can be reused for 8 cycles with no loss of performance by using an external magnet.

Controlling cellulose feedstock size allows for modification of cellulose-based carbon-based solid acid size

Carbon-based solid acids (CSA) have grown in popularity in recent years owing to their strong catalytic activity, thermal stability, and reusability. The size effect has a significant influence on the catalytic activity of carbon-based solid acids in heterogeneous catalysts. The impacts of raw material size on the shape, sulfonation degree, and catalytic activity of produced carbon-based solid acids were examined in this article. Various sizes of microcrystalline cellulose (MCC), cellulose nanocrystals (CNCs), and cotton fiber pulp (CP) were used as carbon sources in a simple carbon-sulphonation method to synthesize carbon-based solid acids. The produced CSA has a high concentration of sulphonic acid groups, as well as hydroxyl and carboxyl groups, and exhibits remarkable catalytic activity for the conversion of xylan to xylose. The solid acids generated from MCC have the most homogeneous shape, the greatest degree of sulphonation, and the highest catalytic activity. The conversion rate of xylan hydrolysis to xylose was up to 58.8% under ideal reaction conditions (150 °C, 4 h), and the catalyst retained almost its initial level of activity after five cycles with no appreciable deactivation.Graphical abstract

A Mini Review on the Development of Conjugated Polymers: Steps towards the Commercialization of Organic Solar Cells

This review article covers the synthesis and design of conjugated polymers for carefully adjusting energy levels and energy band gap (EBG) to achieve the desired photovoltaic performance. The formation of bonds and the delocalization of electrons over conjugated chains are both explained by the molecular orbital theory (MOT). The intrinsic characteristics that classify conjugated polymers as semiconducting materials come from the EBG of organic molecules. A quinoid mesomeric structure (D-A ↔ D+ = A-) forms across the major backbones of the polymer as a result of alternating donor-acceptor segments contributing to the pull-push driving force between neighboring units, resulting in a smaller optical EBG. Furthermore, one of the most crucial factors in achieving excellent performance of the polymer is improving the morphology of the active layer. In order to improve exciton diffusion, dissociation, and charge transport, the nanoscale morphology ensures nanometer phase separation between donor and acceptor components in the active layer. It was demonstrated that because of the exciton's short lifetime, only small diffusion distances (10-20 nm) are needed for all photo-generated excitons to reach the interfacial region where they can separate into free charge carriers. There is a comprehensive explanation of the architecture of organic solar cells using single layer, bilayer, and bulk heterojunction (BHJ) devices. The short circuit current density (Jsc), open circuit voltage (Voc), and fill factor (FF) all have a significant impact on the performance of organic solar cells (OSCs). Since the BHJ concept was first proposed, significant advancement and quick configuration development of these devices have been accomplished. Due to their ability to combine great optical and electronic properties with strong thermal and chemical stability, conjugated polymers are unique semiconducting materials that are used in a wide range of applications. According to the fundamental operating theories of OSCs, unlike inorganic semiconductors such as silicon solar cells, organic photovoltaic devices are unable to produce free carrier charges (holes and electrons). To overcome the Coulombic attraction and separate the excitons into free charges in the interfacial region, organic semiconductors require an additional thermodynamic driving force. From the molecular engineering of conjugated polymers, it was discovered that the most crucial obstacles to achieving the most desirable properties are the design and synthesis of conjugated polymers toward optimal p-type materials. Along with plastic solar cells (PSCs), these materials have extended to a number of different applications such as light-emitting diodes (LEDs) and field-effect transistors (FETs). Additionally, the topics of fluorene and carbazole as donor units in conjugated polymers are covered. The Stille, Suzuki, and Sonogashira coupling reactions widely used to synthesize alternating D-A copolymers are also presented. Moreover, conjugated polymers based on anthracene that can be used in solar cells are covered.

Arylene Diimide Derivatives as Anolyte Materials with Two-Electron Storage for Ultrastable Neutral Aqueous Organic Redox Flow Batteries

Arylene Diimide Derivatives as Anolyte Materials with Two-Electron Storage for Ultrastable Neutral Aqueous Organic Redox Flow Batteries

Fe, Ni-modified ZIF-8 as a tensive precursor to derive N-doped carbon as Na and Li-ion batteries anodes

Carbon materials derived from metal-organic frameworks have attracted increasing attention as anodes for energy storage. In this study, Fe, Ni-doped ZIF-8 is carbonized at high temperature to obtain bimetallic Fe and Ni modified tension -relaxed carbon (FeNi@trC). Fe and Ni have opposite structural modification effects when the metal ions are doped into the ZIF-8 dodecahedron. The obtained carbon material maintains the regular dodecahedron morphology, which means the relaxation of tension and strong thermal stability during annealing. Moreover, the presence of nickel enhances the carbonization degree and electrochemical stability of FeNi@trC, while the calcination of the tensive ZIF-8 precursor offers more defect sites. The discharge capacities of FeNi@trC materials are stable at 182.9 mAh·g−1 and 567.9 mAh·g−1 for sodium-ion batterie (SIB) and lithium-ion batterie (LIB) at 0.05 A·g−1. Compared with the current density of 0.05 A·g−1, the discharge capacity of SIB and LIB attenuates by 29.4% and 55.9% at 1 A·g−1, respectively, and the FeNi@trC shows good performance stability in the following cycles.

Structure and physicochemical properties of low digestible Euryale ferox Salisb. seed starch.

Euryale ferox Salisb. is widely grown in China and Southeast Asia as a grain crop and medicinal plant. The composition, morphology, structure, physicochemical properties, thermal properties, and in vitro digestibility of North Euryale ferox seeds starch (NEFS), hybrid Euryale ferox seeds starch (HEFS), and South Euryale ferox seeds starch (SEFS) were studied. Of the varieties that were studied, the amylose content of NEFS (23.03%) was the highest. Starch granules of each variety were smooth, sharp, small, and had an average diameter of 2μm. All three varieties were A-type crystals with crystallinity ranging from 26.42% to 28.17%. The degree of double helix and the short-range order ranged from 1.9006 to 2.5324 and 1.4294 to 1.6006, respectively. The high proportion of C1 region in NEFS (17.74%) and HEFS (17.66%) were found. Thermodynamic properties inNorth Euryale ferox seeds included the highest onset temperature (To ) (71.43 °C), peak temperature (Tp ) (76.60 °C), conclusion temperature (Tc ) (82.77 °C), enthalpy of gelatinization (ΔH) (12.64 J g-1 ), and peak viscosity (1514 mPa·s). All three varieties maintained a low level of in vitro digestibility, with the highest resistant starch (RS) content (29.57%), the lowest rapidly digestible starch (RDS) content (27.07%), and the slowest hydrolysis kinetic constant (0.0303) in NEFS. The results revealed that the low digestibility of NEFS was attributable to compact granules, high crystallinity, high degree of order, and strong thermal stability. These digestive, physicochemical, and thermodynamic properties provide information for the future application of Euryale ferox seed starch in the food industry. © 2022 Society of Chemical Industry.

Design and fabrication of nano textured superhydrophobic and anti-corrosive silane-grafted ZnO/bio-based polyurethane bilayer coating

Superhydrophobic polymer coatings are receiving special attention for industrial applications due to their multifunctionality behaviour. The advancement in nanotechnology has made it easier to design and fabricate nano-textured superhydrophobic coating on metal surfaces, even though adhesion and durability still remain a challenge. Therefore, the present study focuses on a novel bilayer coating approach for fabricating thermally stable, abrasion tolerant, multi-functional, superhydrophobic surface coating through the chemical bonding at the interface of hydroxy terminated polydimethylsiloxane modified cardanol-based polyurethane and silane grafted ZnO nanoparticles. The silane grafting to the ZnO surface has been confirmed by FT-IR, EDX, and XPS analysis. In addition, the change in crystallinity of unmodified and modified ZnO-based HTPDMS-CPU have been studied using XRD analysis. The superhydrophobic surface coating showed a high contact angle of 151° and contact angle hysteresis of 7° which got reduced after 10 cycles of abrasion to 133° and 12°, respectively. The silane groups at the surface allow ZnO to disperse uniformly and get exposed through the polymer coating while forming the micro/nano scale morphology. Furthermore, the anticorrosion parameters of the superhydrophobic bilayer coating showed corrosion current density (Icorr) value of order 10−9 (A.cm2) and corrosion potential (Ecorr) value of −0.351 (V) with inhibition efficiency (ƞ) of 99.5 % on mild steel. Thus, the superhydrophobicity, along with the excellent anticorrosion properties of this bilayer coating with a strong interface, chemical resistance and thermal stability elaborates its applicability in various fields.

Antibacterial Effect of Cell-Free Supernatant from Lactobacillus pentosus L-36 against Staphylococcus aureus from Bovine Mastitis.

This study sought to analyze the main antibacterial active components of Lactobacillus pentosus (L. pentosus) L-36 cell-free culture supernatants (CFCS) in inhibiting the growth of Staphylococcus aureus (S. aureus), to explore its physicochemical properties and anti-bacterial mechanism. Firstly, the main antibacterial active substance in L-36 CFCS was peptides, which inferred by adjusting pH and enzyme treatment methods. Secondly, the physicochemical properties of the antibacterial active substances in L-36 CFCS were studied from heat, pH, and metal ions, respectively. It demonstrated good antibacterial activity when heated at 65 °C, 85 °C and 100 °C for 10 and 30 min, indicating that it had strong thermal stability. L-36 CFCS had antibacterial activity when the pH value was 2-6, and the antibacterial active substances became stable with the decrease in pH value. After 10 kinds of metal ions were treated, the antibacterial activity did not change significantly, indicating that it was insensitive to metal ions. Finally, scanning electron microscopy, transmission electron microscopy and fluorescence probe were used to reveal the antibacterial mechanism of S. aureus from the aspects of cell morphology and subcellular structure. The results demonstrated that L-36 CFCS could form 1.4-2.3 nm pores in the cell membrane of S. aureus, which increased the permeability of the bacterial cell membrane, resulting in the depolarization of cell membrane potential and leakage of nucleic acid protein and other cell contents. Meanwhile, a large number of ROS are produced and accumulated in the cells, causing damage to DNA, and with the increase in L-36 CFCS concentration, the effect is enhanced, and finally leads to the death of S. aureus. Our study suggests that the main antibacterial active substances of L-36 CFCS are peptides. L-36 CFCS are thermostable, active under acidic conditions, insensitive to metal ions, and exhibit antibacterial effects by damaging cell membranes, DNA and increasing ROS. Using lactic acid bacteria to inhibit S. aureus provides a theoretical basis for the discovery of new antibacterial substances, and will have great significance in the development of antibiotic substitutes, reducing bacterial resistance and ensuring animal food safety.