Surface Modification Of Materials Research Articles

Numerical simulation of laser cladding AlCrCuFeNi2 high-entropy alloy coatings

Laser cladding technology is an advanced material surface modification technology, which has the advantages of good combination of coating and substrate, and environmental protection process. In this paper, for the laser cladding of AlCrCuFeNi2 high-entropy alloy coatings, the effects of different laser powers and scanning speeds on the temperature and velocity fields were analyzed by numerical simulation. In the early stage of laser cladding process, heat transfer is dominated by heat conduction, and in the middle and later stages, convection dominates. Compared with the scanning speed, the laser power has a greater influence on the temperature peak inside the molten pool. The research results can provide a reference for the optimization of process parameters of laser cladding high-entropy alloy coatings.

Influence of Y Nano-Oxide and Its Secondary Phase on Microstructure, Mechanical Properties, and Wear Behavior of the Stainless Steel Coatings Fabricated by Plasma Transfer Arc

Rare-earth is an efficient refiner for surface modification of steel material. This study presents the synergistic influence of Y2O3 nanoparticles (YNPs) and Mn-oxide secondary phase on the microstructure and mechanical properties of 14CrSiMnV coating fabricated by plasma transfer arc cladding process. The results indicated that the residual Y accumulated with Mn, forming a secondary phase oxide particle instead of inclusions or slags during rapid cooling solidification of the coating. Due to enlarged equiaxed grains, declining long-range dendritic grains, and secondary phase strengthening, steel coatings present hybrid-type fracture mechanism, less plastic deformation, and third-body interaction. With an optimal addition of YNPs (0.4 wt.%), the mechanical properties of the steel coating are improved, as indicated by the increase of 92.0% in the tensile strength, increase of 55.6% in the elongation, increase of 11.3% in the microhardness, decrease of 22.2% in wear weight loss, and increase of 28.3% in relative wear resistance.

Cold atmospheric pressure plasmas applications in dentistry

AbstractCold atmospheric pressure plasmas (CAP) is widely used for various therapeutic applications in health care. With the enormous progress in the understanding of plasma physics and development of plasma devices, the application of CAP is greatly promoted in dentistry. The reactive chemical species and electromagnetic radiation generated by CAP can activate and control various biochemical procedures. Therefore, CAP showed promising usage in surface modification of dental materials, biofilm removal, disinfection, endodontic therapy, periodontitis treatment, wound healing, and head and neck cancer control. Therefore, the objective of the present review is to present recently published studies on CAP in dentistry.

Preparation and surface modification of magnesium-based sound absorbing materials via a low-temperature vapor deposition

The poor durability of lightweight cement due to hydrophilic property and porous microstructure limits its extensive application. In this study, a superhydrophobic magnesium-based sound absorbing materials (Mg-SAM) have been prepared using basic magnesium sulfate cement as the matrix material and then modified by a low-temperature vapor deposition (LTVD). The results reveal that an ultrathin film of perfluorodecyltriethoxysilane (PFDTS) can be gently deposited on the surface of Mg-SAM with a water contact angle higher than 150° via a low temperature (65 °C) heating process. The modification mechanism of LTVD can be described as the formation of a self-assembled fluorine-containing film through the condensation reaction between silanols and the hydroxyl groups on the surface of Mg-SAM. The noise reduction coefficient and mechanical strength of Mg-SAM with a density of 280 kg·m−3 reach 0.7 and 1.8 MPa respectively without any change after LTVD treatment. This facile, low-cost LTVD technique is a promising approach for large-scale modification of porous materials.

Enhancement of Thermoplasmonic Neural Modulation Using a Gold Nanorod-Immobilized Polydopamine Film.

Photothermal neural activity inhibition has emerged as a minimally invasive neuromodulation technology with submillimeter precision. One of the techniques involves the utilization of plasmonic gold nanoparticles (AuNPs) to modulate neural activity by photothermal effects ("thermoplasmonics"). A surface modification technique is often required to integrate AuNPs onto the neural interface. Here, polydopamine (pDA), a multifunctional adhesive polymer with a wide light absorption spectrum, is introduced both as a primer layer for the immobilization of gold nanorods (GNRs) on the neural interface and as an additional photothermal agent by absorbing near-infrared red (NIR) lights for more efficient photothermal effects. First, the optical and photothermal properties of pDA as well as the characteristics of GNRs attached onto the pDA film are investigated for the optimized photothermal neural interface. Due to the covalent bonding between GNR surfaces and pDA, GNRs immobilized on pDA showed strong attachment onto the surface, yielding a more stable photothermal platform. Lastly, when photothermal neural stimulation was applied to the primary rat hippocampal neurons, the substrate with GNRs immobilized on the pDA film allowed more laser power-efficient photothermal neuromodulation as well as photothermal cell death. This study suggests the feasibility of using pDA as a surface modification material for developing a photothermal platform for the inhibition of neural activities.

Generation of zinc ion-rich surface via in situ growth of ZIF-8 particle: Microorganism immobilization onto fabric surface for prohibit hospital-acquired infection

Viruses/bacteria outbreaks have motivated us to develop a fabric that will inhibit their transmission with high potency and long-term stability. By creating a metal-ion-rich surface onto polyester (PET) fabric, a method is found to inhibit hospital-acquired infections by immobilizing microorganisms on its surface. ZIF-8 and APTES are utilized to overcome the limitations associated with non-uniform distribution, weak biomolecule interaction, and ion leaching on surfaces. Modified surfaces employing APTES enhance ZIF-8 nucleation by generating a monolayer of self-assembled amine molecules. An in-situ growth approach is then used to produce evenly distributed ZIF-8 throughout it. In comparison with pristine fabric, this large amount of zinc obtained from the modification of the fabric has a higher affinity for interacting with membranes of microorganisms, leading to a 4.55-fold increase in coronavirus spike-glycoprotein immobilization. A series of binding ability stability tests on the surface demonstrate high efficiency of immobilization, >90%, of viruses and model proteins. The immobilization capacity of the modification fabric stayed unchanged after durability testing, demonstrating its durability and stability. It has also been found that this fabric surface modification approach has maintained air/vapor transmittance and air permeability levels comparable to pristine fabrics. These results strongly advocate this developed fabric has the potential for use as an outer layer of face masks or as a medical gown to prevent hospital-acquired infections.

Layered Oxide Cathode-Electrolyte Interface towards Na-Ion Batteries: Advances and Perspectives.

With the ever increasing demand for low-cost and economic sustainable energy storage, Na-ion batteries have received much attention for the application on large-scale energy storage for electric grids because of the worldwide distribution and natural abundance of sodium element, low solvation energy of Na+ ion in the electrolyte and the low cost of Al as current collectors. Starting from a brief comparison with Li-ion batteries, this review summarizes the current understanding of layered oxide cathode/electrolyte interphase in NIBs, and discusses the related degradation mechanisms, such as surface reconstruction and transition metal dissolution. Recent advances in constructing stable cathode electrolyte interface (CEI) on layered oxide cathode are systematically summarized, including surface modification of layered oxide cathode materials and formulation of electrolyte. Urgent challenges are detailed in order to provide insight into the imminent developments of NIBs.

Enhancement of Li+ ion kinetics in boehmite nanofiber coated polypropylene separator in LiFePO4 cells

Boehmite (γ-AlO(OH)) nanofibers (length 90–140 ​nm; dia. ∼15 ​nm) synthesized by low temperature (180 ​°C) hydrothermal method and coated onto both sides of surface modified polypropylene. Ceramic coated composite separator (ALO-PP) shows enhanced thermal and dimensional stability over uncoated polypropylene (PP). Optimum coating thickness is found to be 8 ​μm in each side. Electrochemical properties are investigated by assembling 2032-type coin cells using LiFePO4 as cathode against Li/Li+ in half-cell and Mesocarbon microbeads (MCMB) in full-cell configuration respectively. It is found that composite separator results in improved cell kinetics due to better electrolyte uptake and formation of a Li+ ions buffer reservoir facilitating fast ion transport at high current rates. About 16% higher capacity is observed for ALO-PP over PP at a current rate of C/5. Present results show that nanostructured boehmite could be a promising coating material for surface modification of polyolefin separators not only with improved safety but also with enhanced rate performance.

Surface Modification of Poly(ether ether ketone) by Simple Chemical Grafting of Strontium Chondroitin Sulfate to Improve its Anti-Inflammation, Angiogenesis, Osteogenic Properties.

Besides inducing osteogenic differentiation, the surface modification of poly(ether ether ketone) (PEEK) is highly expected to improve its angiogenic activity and reduce the inflammatory response in the surrounding tissue. Herein, strontium chondroitin sulfate is first attempted to be introduced into the surface of sulfonated PEEK (SPEEK-CS@Sr) based on the Schiff base reaction between PEEK and ethylenediamine (EDA) and the amidation reaction between EDA and chondroitin sulfate (CS). The surface characteristics of SPEEK-CS@Sr implant are systematically investigated, and its biological properties in vitro and in vivo are also evaluated. The results show that the surface of SPEEK-CS@Sr implant exhibits a 3D microporous structure and good hydrophilicity, and can steadily release Sr ions. Importantly, the SPEEK-CS@Sr not only displays excellent biocompatibility, but also can remarkably promote cell adhesion and spread, improve osteogenic activity and angiogenic activity, and reduce the inflammatory response compared to the original PEEK. Therefore, this study presents the surface modification of PEEK material by simple chemical grafting of strontium chondroitin sulfate to improve its angiogenesis, anti-inflammation, and osteogenic properties, and the as-fabricated SPEEK-CS@Sr has the potential to serve as a promising orthopedic implant in bone tissue engineering.

In2O3 surface modification of a Li-rich layered cathode material for boosting electrochemical performance

Lithium-rich layered cathode materials have high specific capacities. However, some drawbacks such as low initial Coulombic efficiency (ICE) and severe capacity/voltage decay during repeated cycling hinder their practical applications. Herein, a pristine Li1.2Mn0.54Ni0.13Co0.13O2 (LMNCO) material is synthesized by the carbonate coprecipitation method and then the In2O3 surface modified LMNCO materials with different amounts of In2O3 are prepared by the facile solvent evaporation and calcination method. The In2O3-modified LMNCO material with 2 wt% In2O3 demonstrates the highest ICE and the best rate capability and cycle stability, which are much superior to those of the pristine LMNCO. This surface modified material exhibits the specific capacities of 268.2 and 109.1 mAh g−1 at the current rates of 0.1C and 5C, respectively. After cycling at 1C rate for 200 cycles, the discharge specific capacity is declined from 176.2 to 140.9 mAh g−1, giving capacity retention of 80.0%. The improved electrochemical performance is ascribed to the surface modification of a moderate amount of In2O3. This surface modification can enhance the electrical conduction and hence the electrochemical reaction activity of the active material without hindering the lithium ion transport through the electrode surface. Moreover, it can suppress the undesirable increasing growing of the solid electrolyte interphase film during the repeated charge/discharge cycling due to the surface side reactions between the active material and the electrolyte.

Effect of Surface Modification for Carbon Cathode Materials on Charge-Discharge Performance of Li-Air Batteries.

Li-air batteries have attracted considerable attention as rechargeable secondary batteries with a high theoretical energy density of 11,400 kWh/g. However, the commercial application of Li-air batteries is hindered by issues such as low energy efficiency and a short lifetime (cycle numbers). To overcome these issues, it is important to select appropriate cathode materials that facilitate high battery performance. Carbon materials are expected to be ideal materials for cathodes due to their high electrical conductivity and porosity. The physicochemical properties of carbon materials are known to affect the performance of Li-air batteries because the redox reaction of oxygen, which is an important reaction for determining the performance of Li-air batteries, occurs on the carbon materials. In this study, we evaluated the effect of the surface modification of carbon cathode materials on the charge–discharge performance of Li-air batteries using commercial Ketjenblack (KB) and KB subjected to vacuum ultraviolet (VUV) irradiation as cathodes. The surface wettability of KB changed from hydrophobic to hydrophilic as a result of the VUV irradiation. The ratio of COOH and OH groups on the KB surface increased after VUV irradiation. Raman spectra demonstrated that no structural change in the KB before and after VUV irradiation was observed. The charge and discharge capacities of a Li-air battery using VUV-irradiated KB as the cathode decreased compared to original KB, whereas the cycling performance of the Li-air battery improved considerably. The sizes and shapes of the discharge products formed on the cathodes changed considerably due to the VUV irradiation. The difference in the cycling performance of the Li-air battery was discussed from the viewpoint of the chemical properties of KB and VUV-irradiated KB.

Ionic liquid modified graphene aerogel as efficient electrode material for supercapacitors based on ionic liquid electrolyte

The simultaneous enhancement of energy density (E) and power density (P) is a highly pursued but difficult task in domain of supercapacitors, which necessitates good electrode/electrolyte compatibility, high electron/ion migration rates, and wide voltage window. Herein, an ionic liquid (IL) assisted hydrothermal reduction and modification tactics is employed to prepare 1-benzyl-3-methyl imidazolium cysteine ([Bzmim][Cys]) IL-modified reduced graphene oxide aerogel material (IL-rGA). The porous texture with suitable pore sizes and IL-modified surface of IL-rGA ensures rapid infiltration and sufficient adsorption of electrolyte ions, and therefore substantially enhances the specific capacitance. The symmetric IL-rGA supercapacitor using 1-ethyl-3-methyl tetrafluoroborate IL electrolyte delivers high E values of 104–33 W h kg−1 in the P range of 944–15,860 W kg−1, these output parameters can meet the requirements in more widespread electric facilities. The current work offers a promising way to enhance and balance the E and P values of carbonaceous supercapacitors via the surface modification of electrode materials and the matching with IL electrolytes.

Experimental installation for study the low-power ICRF plasma at low pressures with equipment for experiment data synchronization

An installation for numerical and experimental studies of low-pressure radio frequency plasma for surface modification of functional materials with equipment for data synchronization are presented. The equipment for data synchronization as well as intermediate results for plasma generation are showed.

Investigation of surface endothelialization on nitinol: Effects of composite hydrogel coatings

BackgroundDue to high metal coverage and high mesh density，flow diverters (FD) are widely used for endovascular reconstruction of cerebrovascular disease. However, incomplete endothelialization, restenosis, and thrombosis hamper the long term clinical success. Thus, an effective coating to accelerate the endothelialization of the cerebrovascular FD raw materials and reduce the incidence of thrombosis and restenosis is needed. MethodsA novel composite hydrogel composed of matrigel and sodium alginate (SA) with different blending ratios, which was cross-linked with calcium chloride, was successfully prepared. The hydrophilicity of the coating surface was detected by measurement of the contact angle, and the surface morphology of the nitinol (NiTi) before and after modification was characterized by scanning electron microscopy (SEM). The elastic modulus was utilized to verify the mechanical properties and plasticity of the coating, and the release experiment was conducted to characterize the composite hydraulic coagulation. Additionally, biocompatibility was tested by in vitro cellular experiments. ResultsThe SEM observations showed that when the concentrations of matrigel and SA were 5 and 3 mg/ml, respectively, cross-linking with 40 mg/ml calcium chloride solution was resulted in formation of the uniform M/SA composite hydrogel coating. The contact angle of M/SA-NiTi was only (32.28 ± 1.55°) (P < 0.0001), indicating a strong hydrophilicity of M/SA-NiTi. The 48 h coating release rate is 61.5%. In addition, M/SA-NiTi exhibited to have better biocompatibility and plasticity than B-NiTi and M-NiTi. ConclusionsMatrigel/sodium alginate composite hydrogel coating has good biocompatibility and low thrombosis characteristics, and strong drug-carrying capacity, which is expected to accelerate the endothelialization after FD implantation. It has also a great potential application value in the surface modification of biological materials.

Superhydrophobic natural melanin-coated cotton with excellent UV protection and personal thermal management functionality

This study presents a new approach to imparting the combined functionalities of superhydrophobicity, UV protection and personal thermal management via the photothermal effect to cotton fabrics. Surface modification of fabrics was carried out by applying coatings containing natural melanin (NM) particles extracted from yak hair and fluorine-free polydimethylsiloxane (PDMS) polymer via a dip-pad-dry-cure process. Different concentrations of NM particles were used in the coatings and the roles of each ingredient in achieving the desired functionalities were investigated. In addition, the relationship between NM content and the resultant durability of the coatings was explored based on the variations in superhydrophobicity, UV protection, photothermal performance, and color strength of the fabrics. The results demonstrated that the non-fluorinated NM/PDMS coatings were highly effective in developing a superhydrophobic cotton fabric with a water contact angle of 164°. The NM-coated fabrics provided a rapid heating effect under near-infrared light and their temperature increased to 38.4–45.3 °C, which was up to 14.7 °C higher than that of pristine cotton. Furthermore, the application of NM particles resulted in an excellent UV protection performance and generated the UV protection factor level of 198.48 on cotton fabrics. Finally, the coated fabrics were highly breathable and showed high stability against 1000 abrasion cycles, 5 accelerated washing tests, and 70 h UV irradiation. These findings provide new pathways in the development of future functional textiles using user-friendly and biocompatible ingredients.

Application of diffuse coplanar surface barrier plasma discharge to polymeric materials

AbstractThe KPR 200 mm plasma reactor is a device designed for the surface modification of various materials. Such a modification occurs by applying a unique type of plasma – plasma generated on a ceramic dielectric. The ceramic dielectric is a durable system with which it is possible to continuously modify the surfaces of materials with such a plasma. The advantage of applying this unique type of plasma is that the modification of the materials occurs at room temperature and atmosphere. However, it is necessary to monitor and observe certain parameters, for example: the selected power, the exposure time of the surfaces of the modified materials, and the distance of the surface from the ceramic dielectric itself. Therefore, in the present paper, the effect of diffuse coplanar surface barrier discharge (DCSBD) plasma discharge on selected polymeric materials was investigated. Plasma impact assessment was also performed using image analysis, that could provide relevant information in the process of plasma‐chemical modification. Changes in the surfaces of the investigated thin polyvynil chloride material, before and after exposure to plasma discharge, were also observed (changes in contact angle, atomic force microscopy).

Surface modification of grafted porous polyvinylidine fluoride membrane with graphene oxide for vanadium redox flow battery

Abstract Vanadium Redox Flow Battery (VRFB) is an energy storage flow battery in whichthe key material for VRFB is the membrane that determines the cost and performance of the battery. Porous membranes have shown a great potential as a membrane due to their high stability, cheap and high selectivity. Poly(vinylidine fluoride) (PVDF) is a type of porous membrane that was extensively studied as a potential material for surface modification due to its thermal and chemical stability, inexpensive and mechanical properties. This study aims to develop a highly selective, high-performance modified PVDF membrane using surface grafting and functionalization for VRFB application using the sonication method. Graphene oxide (GO) is a trending material in the field due to its excellent properties such as being highly resistant to alkaline/acidic and strong mechanical strength, low cost and easily accessible. In this work, GO was functionalized on both sides of grafted PVDF using the sonication technique. Hydrogen bond from modification with GO caused the membrane to be a hydrophilic and FTIR results proved that new peaks appeared which relates to carbon bond from GO. Proton conductivity of modified membrane is recorded higher than commercial VRFB membrane, Nafion.

Effects of ultraviolet irradiation on beta-tricalcium phosphate as a bone graft substitute.

Surface modification of various materials using ultraviolet (UV) irradiation improves their wettability. The purpose of this study was to investigate the wettability of a β-tricalcium phosphate (TCP) surface and the composition changes and bioactivity of β-TCP after UV irradiation. We applied 172nm UV treatment to a β-TCP surface and measured the contact angle before and after UV irradiation. Energy-dispersive X-ray and Fourier transform infrared spectroscopy examinations were performed on the β-TCP disk with or without UV treatment. In an adhesion test of bone marrow cells using β-TCP disks with and without UV irradiation, cell attachment was measured 10, 30, 50, and 70h after β-TCP insertion. UV-irradiated β-TCP osteogenesis and absorption of bone substitutes were evaluated using hematoxylin and eosin and tartrate-resistant acid phosphatase (TRAP) staining in a rabbit sinus model. The contact angle on the TCP surface decreased from 70° to 10° owing to UV irradiation. Conversely, UV irradiation did not change the composition of carbon, oxygen, and phosphorus. In the cell adhesion test, UV-irradiated β-TCP significantly increased cell adhesion compared with UV-unirradiated β-TCP after 10 to 30h of culture. In the rabbit sinus model, TRAP staining showed that UV-irradiated β-TCP significantly increased the number of TRAP-positive cells compared with unirradiated β-TCP granules in the central part of β-TCP. Our results indicate that the UV irradiation of β-TCP improves its clinical utility for surgical bone augmentation in the oral and maxillofacial region.

Phytic Acid-Promoted rapid fabrication of natural polypeptide coatings for multifunctional applications

Surface modification or reconstruction of biomaterials, medical devices or other materials hold great promise for improved functionality and applications. However, it is essential to develop coating layers possessing a wide range of functionalities, such as antibacterial, anticorrosive and biocompatible properties. In this work, a simplified method was investigated for the supramolecular assembly of natural bio compounds, phytic acid (PA) and antimicrobial peptide of ε-polylysine (Ply), via one-pot co-deposition. The PA and Ply formed a coating layer on the substrate surface through the inherent surface affinity of PA and ionic bond formation between the electro-positive Ply and electro-negative PA. The co-deposition of PA-Ply is a surface-independent. The physio-chemical features of PA-Ply on titanium (Ti) were characterized to reveal the polymer decoration, surface composition, and microtopography. It was noticed that the PA-Ply coating on Ti (Ti-PA-Ply) could kill greater than 99.9% of both Gram-positive and Gram-negative bacterial pathogens upon their adhesion as compared to that of the pristine Ti surface. Furthermore, the in vivo rat subcutaneous infection model demonstrated effective anti-infection and bactericidal properties of the Ti-PA-Ply surface. In addition, the PA-Ply coating exhibited anti-corrosive property for medical-grade magnesium (Mg) in an electrochemical corrosion model, and promoted the proliferation of endothelial cells. The versatile PA-Ply coating also imparted an improved anti-fogging performance. Thus, the present one-step co-depostition of PA-Ply provided a simple, envirementelly-benign and sustainable approach to the design and fabrication of multi-functional surfaces.

Lithium zirconate coated LiNi0.8Co0.15Al0.05O2 as a high-performance electrode material for advanced fuel cells

Surface modification of electrode materials could effectively enhance catalytic activity and stability for low temperature solid oxide fuel cells. In this paper, LiNi0.8Co0.15Al0.05O2 (NCAL), material with 1 wt % Li2ZrO3 (LZO) surface coating were successfully synthesized by a simple wet chemical method. The crystal structure, surface morphology and electrochemical properties of the modified NCAL materials were investigated by X-ray diffraction, scanning electron microscopy and photoelectron spectroscopy. The obtained results showed that the NCAL coated with LZO exhibited superior electrochemical performance. According to the EIS results, the polarization resistance of the 1 wt % LZO-modified NCAL based fuel cell at 550 °C was only 0.303 Ω cm2, respectively, which were much lower than pure NCAL (1.33 Ω cm2). The results show that the LZO surfaced coated NCAL could be a promising anode material towards high-performance advanced fuel cells.Combined with XRD and XPS analysis, it can be inferred that: the surface modification of LZO did not affect the structure of the raw material, and during the test, LZO enabled the effective distribution of the oxygen vacancies on the surface of the material, which accelerated the catalytic activity of the electrode during the discharge process.