Excellent Properties Research Articles

Physiochemical and In-Vitro Bioactivity Characterization of Polyvinyl Alcohol / Halloysite Nanotube / Collagen (PVA/HNT/Col) using Freeze-Thawing Method and Spin Coated Technique for Wound Healing Applications

Hydrogels are still relevant instruments that can support and improve the dynamic biological process of wound healing. This paper modified hydrogel film by combining polyvinyl alcohol (PVA), halloysite nanotube (HNT), and collagen using simple freeze-thawing and spin-coating techniques. The modification aims to improve the physiochemical and in-vitro bioactivity of the PVA/HNT hydrogel films via the inclusion of different concentrations of collagen. 0.092 mm PVA/HNT/Col3 hydrogel film was suggested to have excellent morphological properties with 94.11 % porosity. It also has good tensile properties with excellent hydrophilicity performance at 38.40o contact angle and 83.528% swelling capacity compared to other modified films. In-vitro bioactivity suggested that the PVA/HNT/Col3 are safe and non-toxic toward host tissue and can promote healing at 93.12% wound closure after 24 hours of treatment. Hence, this material displays huge potential as a wound healing matrix template.

Room-Temperature Flexible CNT/Fe2O3 Film Sensor for ppb-Level H2S Detection.

Carbon nanotubes (CNTs) had room temperature response, large surface area, and excellent mechanical properties, making them favorable for the design of flexible, wearable, and portable gas sensors. However, CNTs were lacking in response and selective response to different gases, such as H2S. Here, we demonstrated a flexible H2S ppb-level gas sensor based on a carbon nanotube/amorphous Fe2O3 (CNT/Fe2O3) film at room temperature, which was fabricated via a simple one-step solvent-thermal method. The CNT/Fe2O3 film gas sensor exhibited a high selective response to H2S (with a response of 55.1% to 100 ppb H2S), rapid reversible response at room temperature (with a response time of ∼127 s to 100 ppb H2S), and low limit of detection to about 2 ppb. Additionally, the CNT/Fe2O3 film maintained good sensing performance under various bending conditions and could be further fabricated into the fiber gas sensor device via wet stretching, retaining response at the ppb level (with a response of 18.6% to 100 ppb H2S). This research on a flexible gas sensor device based on the CNT film/fiber opened up new possibilities for wearable portable electronic device applications.

Preparation of Tung Oil-Modified Raw Lacquer Films and Application for Mechanical Carving Technique

Raw lacquer, known for its superior performance as a natural liquid coating, boasts excellent physical and mechanical properties as well as durability, making it widely used in manufacturing. However, the high hardness of the lacquer film upon complete curing poses challenges for carving and mechanical engraving. Therefore, it is necessary to study the curing process of lacquer films to obtain films suitable for carving or mechanical engraving. This study involves the preparation of raw lacquer with varying amounts of tung oil added, followed by the measurement of film drying time, surface roughness, glossiness, hardness, and adhesion on substrates to determine the optimal drying conditions. Additionally, SEM analysis of the carved surfaces and FT-IR analysis were used to investigate the impact of tung oil addition on lacquer carving performance and its variation. The results indicate that tung oil, to a certain extent, contributes to a smoother lacquer film but adversely affects film hardness and adhesion to Prunus serotina. However, with an increase in the amount of refined tung oil to 15%, the film exhibits improved glossiness, smoother carving tool marks, and reduced debris, thereby validating the feasibility of mechanical carving of tung oil-modified raw lacquer to some extent.

A detailed investigation on assessing the introduction of hybrid fibres in Geopolymer composites for pavement application

ABSTRACT Geopolymer concrete (GPC) has been widely researched as an emerging sustainable construction material. As GPC possesses excellent mechanical and durability properties, it is highly recommended for the construction of rigid pavements. However, the brittle nature of GPC limits its utilisation in heavy traffic roads, reducing its fatigue life. This study aims to minimise the brittleness of Pavement quality GPC (PQGPC) by adding hybrid fibres (steel fibre + polypropylene fibre). Fresh, hardened and durability properties of hybrid fibre-reinforced pavement quality geopolymer concrete (HGPC) under ambient curing have been analysed. In addition, the experimental study also compared the flexural fatigue life of PQGPC with that of the best HGPC mix. Both fibres were added in the same % (by volume) up to a maximum dosage of 1.25% each. Results show that workability decreases with increased fibre addition, but compressive and flexural strength increases with an increment in the quantity of fibres up to 1%. It was observed that the abrasion resistance and shrinkage resistance also increase with the inclusion of hybrid fibres in HGPC. Fatigue results prove that the fatigue life of HGPC-3 (with 2% hybrid fibres addition) mix under medium and heavy loads is 40% and 28%, higher than PQGPC.

Investigation of Tribological Behavior of PTFE Composites Reinforced with Bronze Particles by Taguchi Method

Reinforced PTFE materials can be designed to show high mechanical stability against harder materials under sliding wear conditions. Especially bearing metal-reinforced PTFE is of high practical interest. In this class of materials, bronze-filled PTFE was reported to obtain high wear resistance, a low coefficient of friction (COF), and excellent self-lubrication properties in sliding conditions. In the statistical approach of this work, PTFE composites reinforced with 25 vol%, 40 vol%, and 60 vol% bronze particles were evaluated against pure PTFE regarding wear behavior under varied wear test parameters, i.e., material, normal load, and sliding speed. Wear tests were planned to use a standard orthogonal array based on the Taguchi design method. An analysis of variance test was utilized to quantify the effects of test parameters on the wear behavior of the bronze/PTFE composites and pure PTFE. According to the variance analysis, the material type has the largest influence on the COF and the specific wear rate (SWR) under test conditions of this work. Both COF and SWR were found to be influenced by the material type (29.83% and 96.16%), the normal load (33.34% and 0.95%), and sliding speed (9.14% and 1.28%). The lowest SWR and COF values were achieved at the optimum wear test conditions where the wear test parameters were 1 m/s sliding speed (A4B2C2) at PTFE + 60 vol.% bronze reinforced composite 50 N application load and 0.32 m/s sliding speed (A4B3C1) at PTFE + 60 vol.% bronze reinforced composite 100 N application load, respectively.

Microstructure and Mechanical Properties of Diamond–Ceramic Composites Fabricated via Reactive Spark Plasma Sintering

In order to prepare diamond composites with excellent mechanical properties under non-extreme conditions, in this study, a diamond–ceramic composite was successfully prepared via reactive spark plasma sintering using a diamond–Ti–Si powder mixture as the raw material. The microstructures and mechanical properties of the diamond–ceramic composite sintered at different temperatures were studied. When the sintering temperature was 1500 °C, the diamond–ceramic composite exhibited a volume density of 3.65 g/cm3, whereas the bending strength and fracture toughness were high at 366 MPa and 6.17 MPa·m1/2, respectively. In addition, variable-temperature sintering activated the chemical reaction at a higher temperature, whereas lowering the temperature prevented excessive graphitisation, which is conducive to optimising the microstructure and mechanical properties of the composite.

Enhancing Perovskite Solar Cells Performance through Tailored Design: Pyridine-Functionalized Phenothiazine Derivatives with Modified End-Capped Acceptor Moieties

Abstract Modifying the end-capped acceptor structural units is a very effective approach to power up the performance of hole-transporting materials. Herein, a new stream of donor- π -acceptor (D- π -A) type pyridine functionalized phenothiazine derivates based donor contributor, resulting in nine newly designed HTMs, by substituting the terminal with thiophene and acceptors moieties respectively to enhance the photovoltaic attributes of perovskite solar cells (PSCs). All newly proposed materials were computationally examined to estimate their optoelectronics, geometrical, and photovoltaic properties using density functional theory (DFT) and time-dependent density functional theory (TD-DFT), and then compared to the reference. For organic hole-transporting materials, a heterocyclic phenothiazine (PTZ) has been proven effective as it has feasible structure modifications, excellent electron-donating properties, and straightforward synthesis. The study of electronic parameters (density of state, frontier molecular orbitals, and electrostatic potential ESP), optical properties (light harvesting efficiency, absorption maxima, dipole moment, and first excitation energies) and charge transfer characteristics (electron-hole overlap, transition density matrix) of designed materials revealed that there is an increase in absorption range under the influence of terminal acceptor groups, with a reduction in bandgap values compared to the reference. A density of state (DOS) graph and HOMO-LUMO schema are evidence of the electron-withdrawing effect of acceptor moieties. Transition density matrix (TDM) analysis proves reliable charger transfer in designed molecules. Reorganization energy values for designed molecules are lower than the reference making charge transfer carriers more efficient. Additionally, solvation-free energy values (-17.28 to -33.19 Kcalmol-1) and higher dipole moments suggest better solubility and surface-wetting properties. In general, our newly derived materials have exceptional charge mobilities with higher absorption and reduced band gap values that make them suitable stable candidates for photovoltaic devices.

Effect of Bamboo Nodes on the Mechanical Properties of Phyllostachys iridescens

Bamboo is a significant natural resource, recognized for its rapid growth, lightweight composition, high strength, and excellent mechanical properties, making it increasingly valuable in the furniture and construction industries. A critical structural aspect of bamboo is its nodes, yet there has been limited research on their impact on bamboo’s mechanical properties. This study investigates the mechanical properties of round bamboo tubes in three different states: internodes (S1), nodes with diaphragm removed (S2), and nodes with diaphragm (S3). The results show that the mechanical properties of S1 are a compressive strength (CS) of 29.72 MPa, a shear strength parallel to grain (SSp) of 11.82 MPa, a radial stiffness (Sr) of 155.59 MPa, an impact toughness (IT) of 20.74 kJ/m2, a modulus of rupture (MOR) of 16.45 MPa, a modulus of elasticity (MOE) of 408.53 MPa, a tensile modulus of rupture parallel to grain (MORT) of 189.62 MPa, and a tensile modulus of elasticity parallel to grain (MOET) of 431.05 MPa. Compared with S1, these above parameters change by CS +11%, SSp 6%, Sr +100%, IT −29%, MOR +5%, MOE +63%, MORT −29%, and MOET −58% in S2 and CS +10%, SSp 28%, Sr +250%, IT −31%, MOR +28%, MOE +92%, MORT −25%, and MOET −42% in S3. It demonstrates that the bamboo diaphragm and nodes significantly influence the mechanical properties of bamboo; they have a significant positive effect on the bending properties across the transverse grain, radial ring stiffness, and shear properties along the grain, but negatively impact the tensile properties along the grain.

Fabrication and Properties of in Situ Cross‐Linked Supramolecular Gel Based on Host‐Guest Interaction

AbstractWater‐cut control is critical to efficient reservoir development. In this investigation, a host‐guest inclusion polymer gels system with self‐assembly features was constructed stemming from the host‐guest recognition mechanism. Subsequently, the elements affecting polymer viscosity were discussed. Eventually, the injectivity and plugging performance of the host‐guest inclusion system were measured by core displacement tests. The results indicated that the optimum synthesis temperature of the host polymer and guest polymer were 30 °C and 40 °C, separately, and the optimum total monomer content should be 20 wt%. The polymer system had excellent thickening properties and shearing resistance resulting from host‐guest inclusion interaction and physical hydrophobic association. Meanwhile, it had better plugging performance than host polymer or guest polymer alone. This profile control agent system provides a novel method for settling deep profile control in oilfields.

Comprehensive Review of Wire Arc Additive Manufacturing for Metallic Functionally Graded Materials

Abstract Functionally graded materials are multifunctional materials, which consist of a spatial modification in composition and microstructure for the definite purpose of controlling variations in various functional properties like mechanical, thermal, and structural. They have been widely utilized in aerospace, healthcare, automobile, and various other industrial applications. Emerging additive manufacturing techniques such as wire arc additive manufacturing are capable of manufacturing complex shapes with gradual variations in composition, microstructure, and customized multifunctional material properties in an additive manner. Metal-based functionally graded materials have been extensively explored in recent times to achieve excellent properties, such as excellent strength and plasticity, good thermal stability, and notable anti-oxidation and anti-wear properties and thus additive manufacturing has proven one of the most necessary techniques to fabricate metal functionally graded materials. This paper intends to offer an in-depth survey of the current leading developments in wire arc additive manufacturing for metallic functionally graded materials and line up researchers, engineers, and industry professionals with an extensive understanding of the potentials, challenges, and opportunities related to wire arc additive manufacturing for functionally graded materials. Additionally, it explores the process parameters for optimizing and analysing various mechanical properties, microstructure, and corrosion behaviour of metal-based functionally graded materials. Early research into the potential of using wire arc additive manufacturing to create various alloys and metal combinations in diverse geometries showcases the many advantages of this emerging manufacturing technology, though further research is needed to justify its commercial application. Therefore, future research directions are proposed based on current findings and the challenges came across.

Photocatalytic Hydrogen Production Using TiO2‐based Catalysts: A Review

AbstractPhotocatalytic water splitting is an environmentally friendly hydrogen production method that uses abundant renewable resources such as water and sunlight. While Titanium dioxide (TiO2) photocatalyst exhibits excellent properties, its high band gap limits absorption to ultraviolet (UV) irradiation, resulting in low photo conversion efficiency. This review explores various modification techniques aimed at enhancing the efficiency of TiO2 under visible light irradiation. Factors influencing the photocatalytic water splitting reaction, such as catalyst structure, morphology, band gap, sacrificial reagents, light intensity, temperature, and potential of Hydrogen (pH) are examined. This review also summarizes different catalyst synthesis methods, and types of photocatalytic reactors, and provides insights into quantum yield. Finally, the review addresses the challenges and future outlook of photocatalytic water splitting.

Microstructure and properties of Cu-Ti alloy designed via machine learning

With the development of information technology, machine learning (ML) has been widely applied in materials science. ML can avoid a multitude of trial and error experiments and improve the efficiency of discovering new materials. Hence, screening the alloys with excellent properties by machine learning is time-saving and effective. In this work, the major element descriptors were screened by importance analysis and correlation analysis as input features, and common ML algorithms were considered to establish ML model. The final ‘composition-process-property’ alloy design strategy was proposed and applied to guide the selection of alloy systems and composition. As a result, the Cu-3Ti-0.3Cr-0.15Mg alloy was screened based on the extreme gradient boosting (XGBoost) model. The ultimate tensile strength and electrical conductivity of 1018 MPa and 20.1% IACS were achieved for the designed alloy, respectively, which is well consistent with the predicted values. The ultra-high strength for the designed alloy can be mainly attributed to the precipitation strengthening. Specifically, the formation of nanoscale β'-Cu4Ti and Cr precipitates during the heat treatment plays a significant role in enhancing the strength of the alloy. This work offers new insights into the design of Cu-Ti alloys with excellent comprehensive properties by employing a machine learning model trained on small data sets, which also provides a potential to be applied to other materials systems.

Ultra flexible silica aerogel with excellent mechanical properties for durable oil-water separation

Flexible Silica aerogel has a broad application prospect in the field of oil-water separation due to its low density and high porosity. However, its poor mechanical properties limit its application and it is a challenge to improve its mechanical properties while maintaining its excellent oil absorption capacity. In this work, we add silica sol to the silica source system formed by vinyltrimethoxysilane (VTMS) and vinylmethyl dimethoxysilane (VMDMS) to prepare silica sol-reinforced flexible silica aerogels by ambient pressure drying. The introduction of silica sol provides more -OH groups that can be used as condensation sites. The hydrolysis products of VTMS and VMDMS undergo dehydration condensation reaction with these exposed -OH groups and co-polymerize, resulting in a more robust three-dimensional porous structure. Silica sol- reinforced vinyl flexible silica aerogel is prepared with excellent mechanical properties. Its maximum strain can reach 80% in 10 compression-decompression cycles without destroying its structure. Its hydrophobic angle was 145.7 °. Most particularly, compared to conventional flexible aerogel,when the silica sol-reinforced vinyl flexible silica aerogel is used in oil-water separation applications, it does not need to be dried after absorbing oil but only mechanically squeezed to expel the absorbed organic solvent. It can be reused hundreds of times, which greatly improves the efficiency of oil-water separation.

First-principles simulation of electronic properties of MoB/Si3N4 superlattices via machine learning

MBene materials and Si3N4 materials have excellent properties, but there are still many technical bottlenecks in the preparation of high-performance and flexible structure electronic device materials. In this paper, MBene is combined with Si3N4 materials to form a superlattice structure, which is composed of six superlattice heterostru ctures. Firstly, the first-principles method was used to study the electronic properties of MBene/Si3N4 superlattice materials. The results show that with the increase of stacking times, the material structure becomes more stable, and the interlayer electrons are transferred from the MoB layer to the Si3N4 layer. Second, in the machine learning part, the Extreme Gradient Boosting (XGBoost) algorithm and the Convolutional Neural Network (CNN) algorithm were used to predict the density of states of six superlattice heterojunctions through ensemble learning, and it was found that the best prediction results were achieved when the input data with a combination of global descriptors and local descriptors were used. The lowest MAE is only 0.03, which not only indicates that the predicted density of states model is excellent, but also proves that the more refined the characterization of the surrounding environment of the atom, the more accurate the prediction of the density of states of the material and the higher the generalization performance of the prediction model.

Surface Modification of Gold Nanorods: Multifunctional Strategies and Application Prospects.

Gold nanorods (AuNRs), as an important type of gold nanomaterials, have attracted much attention in the nano field. Compared with gold nanoparticls, AuNRs have broader application potential due to their tunable localized surface plasmon resonance properties and anisotropic shapes. Yet, conventional synthesis methods using surfactants have limited the use of AuNRs in a variety of fields such as biomedical applications, plasma-enhanced fluorescence, optics and optoelectronic devices. To solve this problem and improve the stability and biocompatibility of AuNRs, researchers in recent years have used surface modification and functionalization to modify AuNRs, among which the introduction of organic ligands to prepare organic/gold hybrid nanorods has become an effective strategy. Organic materials have better toughness and easy processing, and by introducing organic ligands into the surface of AuNRs, the molecular-level composite of organic and inorganic materials can be realized, thus obtaining hybrid nanorods with excellent properties. This paper reviews the research progress of hybrid nanocomposites, and introduces the synthesis methods of AuNRs and the development of surface ligand modification, then summaries the applications of a wide variety of ligands. Also, the advantages and disadvantages of different ligands and their roles in further self-assembly processes are discussed.

Biosynthesis of cobalt oxide nanoparticles and their cytotoxicity against cancer cells mouse colon adenocarcinoma cell line

The application of plant extracts for the biosynthesis of cobalt oxide nanoparticles is eco-friendly, more economical, less toxic, and more biocompatible. In this study, we used Rose hip extract to synthesize cobalt oxide nanoparticles (Co3O4 NPs). The biosynthesized cobalt oxide nanoparticles were characterized by FT-IR spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The PXRD and FTIR analyses confirmed the successful synthesis and the characteristic bands of Co3O4 NPs, respectively. The FESEM image showed that the Co3O4 NPs were approximately spherical morphology with a mean size of 90.77 ± 32.35 nm. The EDX analysis showed the elemental composition contains carbon in the formulation of Co3O4 NPs. The results showed that the plant extracts can be used to synthesiz cobalt oxide nanoparticles with good quality at nanoscale sizes. The as-prepared Co3O4 NPs exhibited excellent cell toxicity properties against mouse colon adenocarcinoma cells, indicating that biosynthesized cobalt oxide nanoparticles have potential applications in cancer and nanomedicine.

High-Performance Broadband Photodetectors Combining Perovskite and Organic Bulk Heterojunction Bifunctional Layers

Perovskite can be used to prepare high-performance photodetectors due to its excellent optical properties. However, the detection range of perovskite photodetectors is mostly limited to the visible light range, restricting their further development and application. In recent years, combining perovskite with organic bulk heterojunctions to prepare photodetectors with broadband detection capability has proven to be an effective strategy. Through this approach, the response spectrum of the photodetector can be flexibly regulated, and organic compounds can improve the perovskite film quality by passivating defects and inhibit the penetration of water molecules in the air, thereby improving the device performance and stability. In this work, we propose and demonstrate the feasibility of combining MAPbI3 perovskite with PTB7-Th:COTIC-4F to prepare high-performance photodetectors with wide spectral response characteristics. With the assistance of an organic bulk heterojunction, the defects of perovskite crystals are effectively passivated, and the detection spectrum of the device is successfully extended to about 1100 nm. As a result, the responsivity achieved is 0.58 A/W, 1.19 A/W, and 1.41 A/W under laser illumination of 532 nm, 808 nm, and 980 nm, with the power density of 5 μW/cm2 at the bias voltage of −0.5 V, respectively, which is one of the best performances among vertical device structures of this type. Moreover, the stability of the final hybrid film has been greatly improved. This work provides a new approach to the preparation of high-performance and broadband perovskite photodetectors.

Tough, antimicrobial, recyclable hydrogel with tree-trunk-inspired core‐sheath structure for efficient all-day desalination

Solar-driven interfacial evaporation, an economically friendly freshwater harvesting technology, faces the challenge of achieving efficient all-day desalination. Inspired by the core‐sheath structure of tree trunks, herein, a hydrogel evaporator features internal vertical lamellar sodium alginate (SA) pores supported by aramid fiber (AF) networks and surface covered with a dense layer of copper sulfide (CuS) and was fabricated through freeze-drying-cycling alternating immersion method. The internal vertical SA lamellar structure endows the hydrogel with strong water transport capability, while the high photothermal conversion ability of the surface CuS layer enables rapid water evaporation. Therefore, as 2D evaporators, the evaporation rate in highly concentrated salt solutions (15 wt%) is up to 2.07 kg m−2 h−1 under 1.0 sun. As 3D evaporators, efficient evaporation is achieved throughout the day by compensating evaporation at the sides and top. Under the irradiation of 0.2 and 0.8 suns outdoors, the evaporation rate of the 3D evaporator can reach 7.47 kg m−2 h−1 and 12.60 kg m−2 h−1, respectively, and its total evaporation is 4.72 times higher than that of the 2D evaporator. Notably, the hydrogel evaporator has excellent anti-salt properties, antimicrobial properties, and recyclability. This work provides valuable guidance for designing and developing practical hydrogel evaporators.

Shining Light on Green Chemistry: BODIPY-infused Porphyrin Nanocomposite-Enzymatic Photocatalyst Boosts Selective Aldehydes Hydrogenation and Organic Transformation under Solar Spectrum

Photo-bio enzyme coupled biotransformation solar radiation driven processes grasp promising in the production of solar driven organic chemicals. Here we reported the synthesis and development of (NH2)4TPP@BODIPY photocatalyst, which was constructed from 5,10,15,20 tetrakis (4 amino phenyl) porphyrin and BODIPY {5,5-difluoro-3,7-bis((E)-4-nitrobenzylidene)-10-(4-nitrophenyl)-5,7-dihydro-3H-4l4,5l4-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinine} molecule through poly-condensation mechanism resulting in the composite formation which manifest excellent light harvesting properties and photocatalytic reactions with suitable satisfactory band gap and formation of huge electrons channels which bears the organic transformation (98%) and photo-regeneration of NADH (66.92%) in 60 minutes which further enhances reduction of aldehyde resulting alcohol production. The highly selective aldehyde hydrogenation process is proposed via coordination of alcohol dehydrogenase with (NH2)4TPP@BODIPY assistant reduces from the coupling process; regeneration of nicotinamide adenine dinucleotide (NADH). Our results show an excellent benchmark for the NAD+ co-factor coupled solar-driven alcohol production via (NH2)4TPP@BODIPY photocatalyst.

Legumes as an alternative protein source in plant-based foods: applications, challenges, and strategies

Since animal proteins may pose a threat to the global environment and human health, the development of alternative proteins has become an inevitable trend in the future. Legumes are considered to be one of the most promising sources of sustainable alternative animal proteins. Legume proteins are considered to exhibit excellent processing properties, including emulsification, gelation, and foaming, which have led to their widespread use in the food industry. Moreover, legume proteins are not only taken as substitutes for meat proteins, they also play an essential role in novel plant-based foods (meat, dairy, fermented food, and fat). However, there are few comprehensive overview studies on the application of legume proteins in plant-based foods. Therefore, this review provides a general overview of the main sources, functional properties, and applications in plant-based foods of legume proteins. In addition, challenges to the application of legume proteins in plant-based foods and specific strategies to address these challenges are presented. The review may provide some references for the further application of legume proteins in novel plant-based foods.