Surface Modification Of Materials Research Articles

Synthesis and antimicrobial activity of yttrium-doped cerium oxide nano-composite against wound pathogen

Abstract Nanocomposite materials have attracted considerable interest in several disciplines owing to their distinctive characteristics and possible uses. The primary objective of this study was to synthesize and characterize a nanocomposite material consisting of cerium that has been doped with yttrium. The shape, structure, and properties of the synthesized nanocomposite was characterized using various characterization techniques including ultraviolet spectrophotometry, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), zeta potential measurements, dynamic light scattering (DLS), and Fourier-transform infrared spectroscopy (FTIR).The antibacterial activity of the nanocomposite was assessed against a range of pathogenic bacteria including Gram-positive bacteria - Enterococcus faecalis, Staphylococcus aureus, and Gram-negative bacteria- Escherichia coli, Pseudomonas aeruginosa using standard microbiological techniques. The results indicate that the nanocomposite possesses strong antibacterial properties against a wide range of microorganisms, showcasing its potential as a highly effective antimicrobial agent for diverse applications in the biological, environmental, and industrial fields. Hemolysis is the process of red blood cell destruction, resulting in the release of hemoglobin into the surrounding fluid. In this study, 0.7:0.3M nanocomposite had showed effective biocompatibility with less than 5%. Furthermore, this particular composite remained identical in different time intervals, while other composites would normally fluctuate. Research has shown that meticulous material design and surface modification can reduce the harmful effects on red blood cells, hence improving the safety of nanocomposite for therapeutic purposes. In summary, this study offers valuable information on the creation, analysis, and assessment of nanocomposite materials with antimicrobial properties.

Electrochemical and bioelectrochemical sulphide removal: A review

AbstractThe increased demand for energy worldwide and the focus on the green shift have raised interest in renewable energy sources such as biogas. During biogas production, sulphide (H2S, HS− and S2−) is generated as a byproduct. Due to its corrosive, toxic, odorous, and inhibitory nature, sulphide is problematic in various industrial processes. Therefore, several techniques have been developed to remove sulphide from liquid and gaseous streams, including chemical absorption, chemical dosing, bioscrubbers, and biological oxidation. This review aims to elucidate electrochemical and bioelectrochemical sulphide removal methods, which are gaining increasing interest as possible supplements to existing technologies. In these systems, the sulphide oxidation rate is affected by the reactor design and operational parameters, including electrode materials, anodic potential, pH, temperature and conductivity. Anodic and bioanodic materials are highlighted here, focusing on recent material developments and surface modification techniques. Moreover, the review focuses on sulphide generation and inhibition in biogas production processes and introduces the prospect of removing sulphide and producing methane in one single bioelectrochemical reactor. This could introduce BESs for combined biogas upgrading and cleaning, thereby increasing the methane content and removing pollutants such as sulphide and ammonia in one unit.

Study on Friction and Wear Performance of Sliding Metal Seal Materials Under Reciprocating Motion.

During petroleum drilling, the reciprocating motion in the seal device leads to piston and sleeve wear, which may cause leakage of the sealing medium. Selecting appropriate materials for the piston and sleeve, along with surface modifications, can effectively prolong the seal service life of the seal. The friction and wear properties of piston and sleeve pairs of different materials in a metal sealing device were simulated by the laboratory "pin-on-block" reciprocating friction test. Pins made of 45# steel, 35CrMo, and 20Cr13 were used to simulate piston bulges, while 35CrMo samples were used to simulate sleeves. Additionally, the influence of DLC (diamond-like carbon) coating and QPQ (Quench-Polish-Quench) nitriding on the wear resistance of the materials was studied. Based on this, the friction and wear properties, along with the wear mechanism of different material pairs, were analyzed. The results show that the friction coefficient curves of the three piston base materials and the 35CrMo sleeve are similar, and the friction coefficient of 45# steel is lower than that of 35CrMo and 20Cr13 at the initial stage. The DLC surface coating exhibited the best anti-wear performance, with the lowest friction coefficient, minimal wear, and the most stable friction coefficient. Surface QPQ nitriding treatment can also improve the wear resistance of the base material. However, due to the oxide formed during nitriding being prone to flaking, the friction coefficient fluctuates significantly at the initial stage of testing, and its anti-wear performance was inferior to that of the DLC coating. This study on material pairing and surface modification provides theoretical support for material selection and surface modification design of pistons and sleeves in oil drilling sealing devices.

تأثير استعمال ليزر النيوديميوم ياك (Nd-YAG) على البنية الدقيقة وصلابة سطح الفولاذ AISI1012

The unique characteristics of the laser beam such as directionality, monochromaticity, and brightness make it a very important tool in the surface treatment engineering. The concentrated heat in the laser beam can be precisely directed toward the processed region on the surface. The laser beam power, beam size, and scanning velocity are easily controlled during the different processing methods. Laser surface modifications of metallic materials, such as laser surface melting, laser surface alloying, and laser cladding are some of the most important methods to improve the mechanical properties of the processed layer on the surface. A pulsed Nd-YAG laser surface melted specimens of low carbon steel with a maximum power of 90W at different processing parameters. The rapid melt and solidification of the treated layer produced a refinement in the microstructure. The original microstructure of this steel (Ferrite + Pearlite) has been transformed to new phases of martensitic and bainitic structures. The melted layer consists of the melted pool, the heat affected zone, and the substrate. The maximum hardness of the laser melted layer is more than 400 HV. The effect of different lasers such as high power CW CO2 laser on the mechanical properties and corrosion resistance of steel alloys will be carried out in future studies. Keywords: Nd-Yag Laser, Laser surface treatment, Microstructure and hardness of AISI1012 steel

Модификация твердофазной полимерной поверхности путём прививки акриловых мономеров

Graft copolymerization onto a solid polymer surface is an effective tool for its modification. A large number of works have been published and require systematization. A search and review of English-language scientific literature devoted to the graft copolymerization of acrylic monomers onto a polymeric solid-phase surface have been carried out. Grafting onto plates and films, as well as fibers and colloidal particles, is considered. It has been revealed that the most popular substrates for graft copolymerization are, besides polyethylene, propylene and polyethylene terephthalate; polyurethanes, polyfluoroethylenes, rubbers, etc. Graft polymerization mainly proceeds on amorphous areas of the substrate and does not destroy the crystalline phase. It is possible to use the methods of controlled radical polymerization (ATRP, RAFT). Of the acrylic monomers, acrylic and methacrylic acids, glycidyl acrylate and glycidyl methacrylate, and others have been used, while the main method has been UV photopolymerization with an initiator–benzophenone. Of the three aliphatic ketones (acetone, methyl ethyl ketone and methyl propyl ketone), acetone has been the best solvent. Cophotoinitiators have been also used (a synergistic effect was observed), corona discharge, gamma radiation (60Co), ozone and plasma treatment, and a supercritical CO2 medium. The degree of grafting has been controlled by changing the soaking time in the monomer, pressure, concentration of monomer and initiator in the liquid phase, reaction temperature and reaction time. A new technology of graft polymerization with photopatterning has also been proposed. Problems of graft polymerization in terms of surface modification of polymer materials (hydrophilization of the surface, improving paintability and wettability, enhancing adhesion to certain surfaces, biocompatibility) are touched upon, and possible areas of their application are outlined.

Research on Solid-State Linear Transformer Driver Power Source Driving Atmospheric Pressure Plasma Jet Treatment of Epoxy Resin

The Solid-State Linear Transformer Driver (SSLTD) is a nanosecond pulse power source characterized by its fast rise time and adjustable output waveform. It can generate uniform and stable atmospheric plasma jets, which is suitable for material surface modification. In this study, a 15-stage SSLTD was designed and assembled, which can produce a stable nanosecond pulse voltage up to 15 times the amplitude of the charging voltage at high frequencies, with a rise time of approximately 10 ns. This device can be used to generate stable atmospheric pressure Ar plasma jets with an electron density in the range of 1015~1016 cm−3 and gas temperatures close to room temperature. After the modification treatment by the plasma jets, the content of the C=O groups on the surface of the epoxy resin significantly increased in the wavelength range of 1720~1740 cm−1, and its flashover resistance was noticeably enhanced. The optimal comprehensive modification effect was achieved at a charging voltage of 600 V, pulse width of 50 ns, and pulse frequency in the range of 800~1000 Hz.

Chiral microporous organic network/covalent organic framework/silica composites: Powerful and versatile chromatographic separation materials

Nowadays, covalent organic framework (COF) has shown great potential in chromatographic separation, and enriching the design of novel COF based stationary phases and broadening their application prospects remains of great significance. Microporous organic network (MON) is a novel type of porous material with large specific surface area and excellent stability connected by covalent bonding, which is extremely similar to COF. Especially, nano-sized MON has the characteristics of easy binding with silica matrix and superior chromatographic separation performance. In this work, the combination of MON and COF as the surface modification materials of silica gel was first explored. The conjugated network structure of MON and COF can improve the permeability of silica stationary phase, and the presence of abundant functional groups in COF and MON can enhance the separation ability for a series of aromatic compounds. Moreover, hydrophilic L-cysteine containing thiol group was cleverly introduced into MON/COF@SiO2via thiol-ene/yne click reactions to balance the hydrophilicity and hydrophobicity of stationary phase. The L-cysteine modified chiral MON/COF@SiO2 (CMON/CCOF@SiO2) was used for effective separation of various chiral/hydrophilic/hydrophobic analytes, and the CMON/CCOF@SiO2 was observed to exhibit superior separation ability to the CCOF@SiO2. Multi-mode chromatographic separation mechanisms were explored, demonstrating that multiple interactions were involved in the separation process. Finally, the CMON/CCOF@SiO2 was applied to detect the environmental endocrine disruptors in the water sample and pyridoxine in the tablet sample, respectively, indicating a great potential for application in actual sample detection.

Proposing an Affordable Plasma Device for Polymer Surface Modification and Microbial Inactivation.

This study proposes an affordable plasma device that utilizes a parallel-plate dielectric barrier discharge geometry with a metallic mesh electrode, featuring a straightforward 3D-printed design. Powered by a high-voltage supply adapted from a cosmetic plasma device, it operates on atmospheric air, eliminating the need for gas flux. Surface modification of polyethylene treated with this device was characterized and showed that the elemental composition after 15 min of plasma treatment decreased the amount of C to ~80 at% due to the insertion of O (~15 at%). Tested against Candida albicans and Staphylococcus aureus, the device achieved a reduction of over 99% in microbial load with exposure times ranging from 1 to 10 min. Simultaneously, the Vero cell viability remained consistently high, namely between 91% and 96% across exposure times. These results highlight this device's potential for the surface modification of materials and various infection-related applications, boasting affordability and facilitating effective antimicrobial interventions.

Cold plasma treatment for E. coli inactivation and characterization for fresh food safety

Cold plasma is an emerging non-thermal technology for food pathogen inactivation and material surface modification. This technology was demonstrated ecofriendly and convenient with free of chemicals in food processes. The presenting study was to investigate the effectiveness of reactive species generated in cold plasma treated water (CPTW) for inactivating microbes through oxidative stress. The physical properties of CPTW created by electric discharges of O2/N2 were characterized. The potential of CPTW for fresh food applications was evaluated. The research results revealed that the pH values of CPTW significantly decreased from pH 7.4 to 3.4 and the electrical conductivity of CPTW increased from 78 to 162 mS/cm when treatment time increased from 10 to 240 s at the discharge frequency of 2000 Hz. It's demonstrated that the CPTW was able to significantly inactivate E. coli TOP 10 in water. The substantial reduction in E. coli TOP 10 cells increased from 1.6 to 8 log at a frequency of 2000 Hz when the treatment times changed from 10 to 240 s. It's also verified that the CPTW significantly reduced the bacterial load and extended the shelf life of the strawberries up to 30 days without compromising their quality compared to untreated control samples. This information is useful for the design of effective cold plasma processes in food engineering applications. Further research is necessary to explore the full potential of cold plasma technology in enhancing food safety and quality in the future.

DFT-based investigation of polyetherketoneketone materials for surface modification for dental implants

BackgroundPolyetherketoneketone (PEKK) is a high-performance thermoplastic polymer with unique structural and mechanical properties that make it a promising candidate for surface modification of dental implants. This study was conducted to investigate the feasibility of PEKK for this purpose using the Cambridge Serial Total Energy Package (CASTEP) code based on density functional theory (DFT).MethodsThis study examined the ground state energy, structural properties, thermodynamic behavior, cohesive energy, refractive index, stress analysis, mechanical properties, and anisotropic behavior of PEKK.ResultsThis study found that PEKK has a complex crystal structure with an orthorhombic unit cell shape, triclinic lattice type, and a centered structure. It also has a 2D layered structure owing to the presence of carbonyl groups, which provides a large surface area for interaction with biological tissues. Thermodynamic analysis showed that PEKK exhibited bond elongation and structural changes at 380 °C, indicating thermal degradation. The cohesive energy of PEKK was calculated to be – 440 eV, indicating its stability and structural integrity. PEKK has a complex refractive index, with real and imaginary components that affect its optical properties. Stress analysis showed that PEKK is resistant to shear deformation and has high hydrostatic stress, which contributes to its stability and biocompatibility.ConclusionThe mechanical properties of PEKK, including its high stiffness, resistance to volume change under pressure, and ability to accommodate natural movements, make it suitable for surface modification of dental implants.

Comprehensive study of plasma polymerization parameters on thiol-coated LDPE films for effective fibronectin adsorption targeting biomedical applications

In the realm of biomedical applications, biocompatible materials with optimized surface properties are crucial for facilitating cellular interactions. To attain the perfect balance of these properties, surface modification of non-toxic and stable bulk materials is often required. Within this context, this research aimed to improve the physiochemical and cell-responsive properties of a low-density polyethylene film. This was achieved by depositing thiol-rich coatings using a dielectric barrier discharge plasma reactor operating at medium pressures, with 1-propanethiol serving as polymerization precursor. The study systematically investigated the impact of key plasma polymerization parameters, including DBD chamber pressure, treatment time, and the combination of precursor flow rate and discharge power represented by the Yasuda parameter, to identify optimal plasma processing conditions for the formation of thiol-rich coatings. To characterize the coating thickness, hydrophilicity and surface chemical composition, atomic force microscopy, water contact angle measurements, and X-ray photoelectron spectroscopy were employed. The findings indicated that reducing the chamber pressure to 10 kPa led to more hydrophilic and thicker deposits possessing a higher sulphur content. Deposition time (5 to 15 min) also significantly impacted coating thickness and surface chemistry, where long times increased thickness, but also led to a reduced sulphur and increased oxygen content because of more pronounced etching. The optimal deposition time was therefore set at 10 min resulting in the deposition of dense coatings possessing a high number of sulphur-containing functionalities. The Yasuda parameter (W/FM) analysis demonstrated optimal thiol incorporation in combination with high coating stability at an intermediate W/FM value of 72 MJ/kg. Following the determination of the optimal plasma polymerization parameters, the effectiveness of thiol plasma polymerization and subsequent fibronectin immobilization for enhancing cell adhesion and proliferation was investigated. The thiol-coated substrates were found to exhibit superior protein immobilization, because of the high affinity for protein binding of the available thiol groups. To assess cellular responses, Schwann cells were cultured on uncoated and coated samples before and after fibronectin immobilization. The results revealed a superior cellular response of the thiol-coated samples after fibronectin immobilization, showing the highest cell viability and significantly enhanced cell adhesion and proliferation. Collectively, these results underscore the synergistic effect of thiol plasma polymerization and fibronectin immobilization in promoting the cellular response of LDPE substrates, thus highlighting their potential as a surface modification strategy of biomaterials.

Novel Application of Diffuse Coplanar Surface Barrier Discharge: Fast, Efficient and Controlled Surface Functionalization

Plasma chemistry is currently an interesting approach to surface modification of materials. In general plasma treatment is a fast process, affecting only the units of nanometers of the surface layer without altering the bulk properties. and has many potential benefits such as minimal waste and control of surface functionality. It represents a dry and environmentally friendly process that can achieve comparable results to wet chemical treatment. The research and development of plasma sources, mainly operating at atmospheric pressure, has been the main activity of the centre CEPLANT, Brno, Czech Republic for several decades. Our development is generally aimed at fast, efficient, and low-cost plasma treatments, easily implementable in industry, and flexibly responds to industrial requirements and current trends.One of our most versatile plasma source, the so-called Diffuse Coplanar Surface Barrier Discharge (DCSBD) has been developed for in-line surface modification of various materials, primarily for fabric materials. DCSBD produces a 0.3 mm thin layer of non-equilibrium, cold macroscopically diffuse plasma at atmospheric pressure (Fig. 1) in any working gas, including oxygen, hydrogen, or even water vapors. Due to its strongly non-equilibrium nature, operation at atmospheric pressure, and low temperatures, the DCSBD represents a unique plasma source suitable for surface modification of low-cost and temperature-sensitive materials [1-4].Unique results have been achieved in research on the practical application of flexible conductive layers on glass, with a focus on the deposition of transparent organic polymer coatings on ultra-thin flexible glass (UTFG). We have developed and optimized efficient and fast dry non-contact cleaning and activation of fragile and lightweight conductive glasses using DCSBD. The high-speed plasma treatment corresponding to the exposure times in the order of units of seconds leads to a synergistic balance between the efficient removal of impurities (carbohydrates) adsorbed on the UTFG surface and the formation of oxygen-based functional groups. Subsequent PEDOT:PSS-based coatings sprayed on plasma-treated UTFG surfaces achieve significantly higher electrical conductivity compared to the standard liquid-purified samples. This method combined with the unique properties of UTFG provides prospective results applicable in microelectronics, and optoelectronic devices like sensors or displays.In the field of composite materials research, we have discovered that plasma treatment of reinforcing fibers leads to improvement of the mechanical properties of laminated fiber-reinforced polymer (FRP) composites. Efficient functionalization of various commonly used reinforcement fibers (flax, aramid and glass) in atmospheric low-temperature DCSBD increases the interfacial adhesion at the fiber-matrix interface, which has a provable positive effect on the resulting mechanical properties.DCSBD plasma can also be utilized for the initiation of reducing chemical reactions. We have developed a simple and fast chemical-free fabrication method of 2D and 3D reduced graphene oxide (rGO) structures using an electrical plasma-triggered reduction & exfoliation of 3D porous graphene oxide (GO) aerogel-like materials [4] and also 2D GO paper-like films starting at temperatures not higher than 100 oC [5]. The plasma triggered the self-propagating reduction & exfoliation fast modification of GO into rGO, while the rGO structures retained their original shape without abrupt disintegration. We observed an approximately 105 fold decrease of the rGO paper resistivity compared to the unmodified GO paper. This novel method opens new opportunities for the production of conductive rGO and rGO-based composites for modern industrial applications.Innovative results were achieved in the fabrication of ZnO nanofibers by a novel calcination approach assisted by DCSBD. Exposition of the polyvinyl pyrrolidone/zinc acetate fibers to DCSBD before the thermal processing leads to the gentle low-temperature removal of organic material. Plasma pre-treated nanofibers are characterized by a smaller diameter and retain a defined fibrous structure during heat treatment. Moreover, the ZnO nanofibers prepared by a combination of plasma and heat treatment exhibited considerably higher photodegradation activity increasing with decreasing calcination temperature [6]. The low-temperature and high oxidation potential of plasma makes plasma-assisted calcination of the inorganic nanofibers an attractive alternative to conventional thermal annealing with potential application in optoelectronics or biosensors.The mentioned applications are only a small fragment of available cases of utilization of the DCSBD, which is now commonly established and applied in the field of surface modification of various materials (glass, metals, non-woven fabrics, polymers, paper, nanofibres) and biomaterials (seeds, grains, wood, natural leather).[1] M. Černák et al., Plasma Physics and Controlled Fusion 53 (2011) 1-8[2] R. Talviste et al., Surface and Interface 16 (2019) 2468-0230[3] T. Morávek et al., Open Chemistry 13 (2015) 236-244[4] R. Krumpolec et al., Flatchem 35 (2022)[5] F. Zelenák , Carbon N. Y. 215 (2023) 118436[6] V. Medvecká et al., Applied Surface Science, 581 (2022) 152384 Figure 1

(Invited) Carbon Sulfonation Using Plasma: Trial to Enlarge Treatment Capacity

Heterogeneous catalysis is a promising technology in conversion of biomass to biofuels because of its high reactivity, easy post-separation, and great recyclability compared to homogeneous catalysis. Various functionalized catalytic materials have emerged as promising alternatives to the homogeneous liquid acid catalyst, such as carbon materials, metal–organic frameworks, and metal nanoparticles. Among them, carbon materials such as carbon nanotube, graphene oxide, carbon black, and so on have been investigated as catalysts for cellulose hydrolysis to produce glucose.Carbon materials show considerable catalytic activity by functionalization with active acidic groups including hydroxyl groups (-OH), carboxyl groups (-COOH), and sulfonic groups (-SO3H). Hydroxyl and carboxyl groups on the carbon catalysts act as connection center to access cellulose, where sulfonic group serves as the active site to cut off the linkage between glucose units in cellulose. So, the surface modification of carbon materials with these functional groups, namely, carbon sulfonation process, becomes the determining step to producing efficient carbon acid catalysts. Conventional methods for the carbon sulfonation are the hydrothermal and reflux method, in which hazardous chemicals are necessary, such as concentrated sulfuric acid (95–98%), chlorosulfonic acid, fuming sulfuric acid, or 4-benzenediazoniumsulfonate under elevated temperature for dozens of hours.As a green and effective carbon sulfonation process, we have utilized plasma generated in contact with dilute sulfuric acid. Recently, we have investigated the mechanism of carbon sulfonation in GLIP processes. Active species produced near the gas–liquid interface such as •OH, SO3, and HOSO2• probably play important roles in carbon sulfonation. We are currently trying to enlarge the treatment capacity of carbon sulfonation by two methods, namely parallel plasma generation with ballast capacitors and large-area plasma generation by a dielectric barrier discharge. Also, effects of gases used for plasma generation such as air and Ar on the carbon sulfonation are investigated.This work was partially supported by the Environment Research and Technology Development Fund (JPMEERF20223R01) of the Environmental Restoration and Conservation Agency of Japan.

Effect of Pinless Friction Stir Processing on Microstructure and Properties of Surface Modification Layer of 2024 Aluminum Alloy

Abstract Friction stir processing (FSP) is an advanced material surface modification technology that is both green and energy-efficient. This technology plays a crucial role in regulating the surface microstructure of alloys and improving their material surface properties. It achieves this through the synergistic effect of non-equilibrium thermodynamics and surface mechanical deformation. In this work, the surface modification of an aluminum alloy was performed using pin-less FSP. And the modified surface was then analyzed using stress-strain curves, optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electrochemical tests to investigate the impact of spindle velocity on the modified layer's properties. Results of the study show after undergoing pin-free FSP modification treatment, the surface of the alloy appears bright and flat. The modified layer displays refined grains and numerous dispersed second-phase particles. Furthermore, the grains in the modified layer exhibit a gradient distribution from the surface to the matrix. Regarding the properties, Compared to the base material (BM), the yield strength (σ0.2) and tensile strength (σb) of the alloy-modified layer were increased by 34.8% and 29.4%, respectively. The maximum elongation (δ) of the modified coating reached 22.3%. The modified layer exhibits a tough-brittle mixed fracture pattern. Additionally, the modified layer's corrosion resistance significantly improves. The performance of the modified coating shows the most significant improvement when the spindle speed reaches 1000 rpm. The study aims to explore the effect of spindle speed on the properties of alloy-modified layers produced by FSP without a stirring pin. This research could be used to create superior metal matrix composites by adding reinforcement particles.

Porous Silica Nanomaterials as Carriers of Biologically Active Natural Polyphenols: Effect of Structure and Surface Modification.

For centuries, humans have relied on natural products to prevent and treat numerous health issues. However, biologically active compounds from natural sources, such as polyphenols, face considerable challenges, due to their low solubility, rapid metabolism, and instability, which hinder their effectiveness. Advances in the nanotechnologies have provided solutions to overcoming these problems through the use of porous silica materials as polyphenol carriers. These materials possess unique properties, such as a high specific surface area, adjustable particle and pore sizes, and a surface that can be easily and selectively modified, which favor their application in delivery systems of polyphenols. In this review, we summarize and discuss findings on how the pore and particle size, structure, and surface modification of silica materials influence the preparation of efficient delivery systems for biologically active polyphenols from natural origins. The available data demonstrate how parameters such as adsorption capacity, release and antioxidant properties, bioavailability, solubility, stability, etc., of the studied delivery systems could be affected by the structural and chemical characteristics of the porous silica carriers. Results in the literature confirm that by regulating the structure and selecting the appropriate surface modifications, the health benefits of the loaded bioactive molecules can be significantly improved.

Tailoring Oxygen‐Depleted and Unitary Ti3C2Tx Surface Terminals by Molten Salt Electrochemical Etching Enables Dendrite‐Free Stable Zn Metal Anode

AbstractTwo‐dimensional Ti3C2Tx MXene materials, with metal‐like conductivities and versatile terminals, have been considered to be promising surface modification materials for Zn‐metal‐based aqueous batteries (ZABs). However, the oxygen‐rich and hybridized terminations caused by conventional methods limit their advantages in inhibiting zinc dendrite growth and reducing corrosion‐related side reactions. Herein, −O‐depleted, −Cl‐terminated Ti3C2Tx was precisely fabricated by the molten salt electrochemical etching of Ti3AlC2, and controlled in situ terminal replacement from −Cl to unitary −S or −Se was achieved. The as‐prepared −O‐depleted and unitary‐terminal Ti3C2Tx as Zn anode coatings provided excellent hydrophobicity and enriched zinc‐ionophilic sites, facilitating Zn2+ horizontal transport for homogeneous deposition and effectively suppressing water‐induced side reactions. The as‐assembled Ti3C2Sx@Zn symmetric cell achieved a cycle life of up to 4200 h at a current density and areal capacity of 2 mA cm−2 and 1 mAh cm−2, respectively, with an impressive cumulative capacity of up to 7.25 Ah cm−2 at 5 mA cm−2//2 mAh cm−2. These findings provide an effective electrochemical strategy for tailoring −O‐depleted and unitary Ti3C2Tx surface terminals and advancing the understanding of the role of specific Ti3C2Tx surface chemistry in regulating the plating/stripping behaviors of metal ions.

Tailoring Oxygen-Depleted and Unitary Ti3C2Tx Surface Terminals by Molten Salt Electrochemical Etching Enables Dendrite-Free Stable Zn Metal Anode.

Two-dimensional Ti3C2Tx MXene materials, with metal-like conductivities and versatile terminals, have been considered to be promising surface modification materials for Zn-metal-based aqueous batteries (ZABs). However, the oxygen-rich and hybridized terminations caused by conventional methods limit their advantages in inhibiting zinc dendrite growth and reducing corrosion-related side reactions. Herein, -O-depleted, -Cl-terminated Ti3C2Tx was precisely fabricated by the molten salt electrochemical etching of Ti3AlC2, and controlled in situ terminal replacement from -Cl to unitary -S or -Se was achieved. The as-prepared -O-depleted and unitary-terminal Ti3C2Tx as Zn anode coatings provided excellent hydrophobicity and enriched zinc-ionophilic sites, facilitating Zn2+ horizontal transport for homogeneous deposition and effectively suppressing water-induced side reactions. The as-assembled Ti3C2Sx@Zn symmetric cell achieved a cycle life of up to 4200 h at a current density and areal capacity of 2 mA cm-2 and 1 mAh cm-2, respectively, with an impressive cumulative capacity of up to 7.25 Ah cm-2 at 5 mA cm-2//2 mAh cm-2. These findings provide an effective electrochemical strategy for tailoring -O-depleted and unitary Ti3C2Tx surface terminals and advancing the understanding of the role of specific Ti3C2Tx surface chemistry in regulating the plating/stripping behaviors of metal ions.

Enhancing camptothecin loading and release control through physical surface modification of organosilica nanoparticles with polyethylene glycol

The surface modification of nanoparticles holds the potential to enhance the loading capacity of drug molecules and regulate their release, making it possible to exploit the differences between tumor and normal cells. To this end, the surfaces of tetrasulfide-based phenylene-containing biodegradable periodic mesoporous organosilica (BPMO) nanoparticles (designated P4S) are modified herein with a hydrophilic and biocompatible polyethylene glycol (PEG) polymer. The PEG coating is optimized by adjusting the PEG concentration during synthesis, thus resulting in a significant increase in the nanoparticle stability. Furthermore, PEG modification enhances the nanoparticles' camptothecin (CPT) loading capacity. Drug release assessments under physical and acidic pH conditions demonstrate the pH-responsive properties of the P4S nanoparticles upon PEG functionalization, which results in increased drug release at low pH, along with enhanced cellular uptake potential. Notably, the cytotoxicity of CPT against HepG2 cancer cells is significantly improved when loaded into the P4S-PEG nanoparticles. These findings reveal the efficacy of PEG surface modification of the drug-delivery material in augmenting the activity of CPT, with promising prospects for clinical applications.

The Influence of Surface Modification of Porous Materials to Improve the Efficiency of Separation of Water-Oil Emulsions: A Review

The Influence of Surface Modification of Porous Materials to Improve the Efficiency of Separation of Water-Oil Emulsions: A Review

Long-Term Prevention of Biofilm Formation by Polycatechol-Based Supramolecular Assemblies with Low Molecular Weight Polymers on Surfaces.

Achievement of a stable surface coating with long-term resistance to biofilm formation remains a challenge. Catechol-based polymerization chemistry and surface deposition are used as tools for surface modification of diverse materials. However, the control of surface deposition of the coating, surface coverage, coating properties, and long-term protection against biofilm formation remain to be solved. We report a new approach based on supramolecular assembly to generate long-acting antibiofilm coating. Here, we utilized catechol chemistry in combination with low molecular weight amphiphilic polymers for the generation of such coatings. Screening studies with diverse low molecular weight (LMW) polymers and different catechols are utilized to identify lead compositions, which resulted in a thick coating with high surface coverage, smoothness, and antibiofilm activity. We have identified that small supramolecular assemblies (∼10 nm) formed from a combination of polydopamine and LMW poly(N-vinyl caprolactam) (PVCL) resulted in relatively thick coating (∼300 nm) with excellent surface coverage in comparison to other polymers and catechol combinations. The coating properties, such as thickness (10-300 nm) and surface hydrophilicity (with water contact angle: 20-60°), are readily controlled. The optimal coating composition showed excellent antibiofilm properties with long-term (>28 days) antibiofilm activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) strains. We further utilized the combination of optimal binary coating with silver to generate a coating with sustained release of silver ions, resulting in killing both adhered and planktonic bacteria and preventing long-term surface bacterial colonization. The new coating method utilizing LMW polymers opens a new avenue for the development of a novel class of thick, long-acting antibiofilm coatings.