Surface Modification Technology Research Articles

Strategy for Surface Post-Processing of AISI 316L Additively Manufactured by Powder Bed Fusion Using Ultrasonic Nanocrystal Surface Modification

Ultrasonic nanocrystal surface modification (UNSM) technology was applied to the surfaces of specimens additively manufactured by powder bed fusion (PBF). The changes in roughness and hardness due to the UNSM were set as objective functions, and the optimal conditions for the main parameters were derived through the response surface method (RSM) and Box–Behnken design (BBD). Regression analysis-based mathematical models for predicting the surface hardness and roughness are presented and validated. The RSM results show that the surface roughness is highly dependent on the load and ball tip diameter, and the surface roughness significantly improves as the inter-pass interval and ball tip diameter decrease. Through BBD and ANOVA, the optimal conditions for the improvement of surface characteristics were found to be a load of 40 N, inter-pass interval of 10 μm, and ball tip diameter of 2.38 m. The surface treated under these optimal conditions exhibited a hardness of 497 Hv and surface roughness of 1.32 μm, which were significantly improved compared to the values for an untreated specimen. In addition, it was confirmed that the grains are significantly refined after UNSM, and scratch resistance increases for the top layer of the surface directly affected by the UNSM horn.

Polymer Scaffolds for Biomedical Applications in Peripheral Nerve Reconstruction.

The nervous system is a significant part of the human body, and peripheral nerve injury caused by trauma can cause various functional disorders. When the broken end defect is large and cannot be repaired by direct suture, small gap sutures of nerve conduits can effectively replace nerve transplantation and avoid the side effect of donor area disorders. There are many choices for nerve conduits, and natural materials and synthetic polymers have their advantages. Among them, the nerve scaffold should meet the requirements of good degradability, biocompatibility, promoting axon growth, supporting axon expansion and regeneration, and higher cell adhesion. Polymer biological scaffolds can change some shortcomings of raw materials by using electrospinning filling technology and surface modification technology to make them more suitable for nerve regeneration. Therefore, polymer scaffolds have a substantial prospect in the field of biomedicine in future. This paper reviews the application of nerve conduits in the field of repairing peripheral nerve injury, and we discuss the latest progress of materials and fabrication techniques of these polymer scaffolds.

Improving the activity and stability of Ni-based electrodes for solid oxide cells through surface engineering: Recent progress and future perspectives

Solid oxide cells (SOCs) have attracted great attention in the past decades because of their high conversion efficiency, low environmental pollution and diversified fuel options. Nickel-based catalysts are the most widely used fuel electrode materials for SOCs due to the low price and high activity. However, when hydrocarbon fuels are employed, nickel-based electrodes face serious carbon deposition challenges, leading to a rapid decline of cell performance. Great efforts have been devoted to understanding the occurrence of the coking reaction, and to improving the stability of the electrodes in hydrocarbon fuels. In this review, we summarize recent research progress of utilizing surface modification to improve the stability and activity of Ni-based electrodes for SOCs by preventing carbon coking. The review starts with a briefly introduction about the reaction mechanism of carbon deposition, followed by listing several surface modification technologies and their working principles. Then we introduce representative works using surface modification strategies to prevent carbon coking on Ni-based electrodes. Finally, we highlight future direction of improving electrode catalytic activity and anti-coking performance through surface engineering.

Growing antifouling fluorinated polymer brushes on polyvinyl alcohol hydrogel surface via g-C3N4@InVO4 catalyzed surface-initiated photo atom transfer radical polymerization

A novel g-C3N4@InVO4 semiconductor catalyzed surface-initiated photo atom transfer radical polymerization without catalysts residues problem has been developed. This method proceeded in N-methyl pyrrolidone/aqueous under atmospheric conditions. To verify the versatility of this method and enhance the antifouling properties of polyvinyl alcohol (PVA) hydrogel, two types of fluorinated polymer brushes (p6F/p13F) were successfully constructed on PVA hydrogel surface instead of the subsurface. The chemical bonds between PVA matrix and fluorinated polymer brushes (p6F/p13F) enhanced the surface cross link density and resulted in an increase of thermal stability and mechanical properties. All fluorinated PVA hydrogels with excellent antifouling properties was able to tackle the biofouling problem in complex environment of the human body. In addition, all fluorinated PVA hydrogels was no cytotoxicity for L929 and NDHF according to ISO 10993.5:2009. g-C3N4@InVO4 catalyzed SI-photoATRP provides a novel surface modification technology for various biological or medical materials in the industrial-scale application.

Exploring the corrosion behavior of Mn-implanted biomedical Mg

Many surface modification technologies have been developed on biomedical magnesium (Mg) and its alloys to expand potential clinical applications. In this study, the bio-safe manganese (Mn) element was implanted into the biomedical Mg surface by a metal vapor vacuum arc (MEVVA) technique. In the Mn-implanted layer, Mn existed in the form of both metallic and oxidized states. Besides, Mn ion implantation changed the corrosion behavior of biomedical Mg in Hank’s solution. At the initial stage of immersion, the corrosion rate was accelerated owing to the galvanic couple between metallic Mn and Mg, and micro-scale galvanic corrosion was uniformly distributed on surfaces. With the immersion time prolonging, Mn-implanted Mg displayed enhanced anti-corrosive property, presenting as a change from corrosion prone to corrosion resistance. On the one hand, the anti-corrosive and uniform Ca, P-containing products were formed on the corroded surface based on uniformly-distributed micro-scale pitting corrosion. On the other hand, the metallic Mn tended to be oxidized to stable Mn oxide so that galvanic corrosion was retarded. This research attempts to explore the effect of Mn ion implantation on the corrosion behavior of biomedical Mg, and offers new insight into novel surface modifications of biomedical Mg devices for long-time implantation.

Using Hybrid Organic-Inorganic Surface Technology to Mitigate Analyte Interactions with Metal Surfaces in UHPLC.

Interactions of analytes with metal surfaces in high-performance liquid chromatography (HPLC) instruments and columns have been reported to cause deleterious effects ranging from peak tailing to a complete loss of the analyte signal. These effects are due to the adsorption of certain analytes on the metal oxide layer on the surface of the metal components. We have developed a novel surface modification technology and applied it to the metal components in ultra-HPLC (UHPLC) instruments and columns to mitigate these interactions. A hybrid organic-inorganic surface, based on an ethylene-bridged siloxane chemistry, was developed for use with reversed-phase and hydrophilic interaction chromatography. We have characterized the performance of UHPLC instruments and columns that incorporate this surface technology and compared the results with those obtained using their conventional counterparts. We demonstrate improved performance when using the hybrid surface technology for separations of nucleotides, a phosphopeptide, and an oligonucleotide. The hybrid surface technology was found to result in higher and more consistent analyte peak areas and improved peak shape, particularly when using low analyte mass loads and acidic mobile phases. Reduced abundances of iron adducts in the mass spectrum of a peptide were also observed when using UHPLC systems and columns that incorporate hybrid surface technology. These results suggest that this technology will be particularly beneficial in UHPLC/mass spectrometry investigations of metal-sensitive analytes.

Boosting electrocatalytic activity of Ni2P nanosheets via incorporation of Ru nanoparticles for efficient hydrogen generation in alkaline media

In order to achieve cost-effective hydrogen production, the development of efficient and stable electrocatalysts for alkaline water splitting has aroused wide attention recently. Here, Ni2P nanosheets arrays decorated with ruthenium nanoparticles are grown in situ on a carbon cloth substrate (denoted as Ru-Ni2P/CC) via surface modification engineering, exhibiting good electrical conductivity and superior hydrophilicity. The resulting Ru-Ni2P/CC-5 with Ru content of 8.98 wt% exhibits an ultra-low overpotential of only 23 mV to achieve a current density of 10 mA cm−2 for hydrogen evolution reaction (HER) and good long-term stability in alkaline solution. The corresponding X-ray photoelectron spectroscopy characterization displays the strong electron interaction between Ru and Ni2P, which facilitates the regulation of their internal electron configuration. Density functional theory calculations reveal that the Ni sites in Ni2P nanosheets are conducive to the dissociation of water molecules owing to lower energy barrier, while Ru sites act as catalytic active center for the production of molecular hydrogen. The present work offers a reasonable design route of efficient electrocatalyst for HER in alkaline solution.

Nanostructured Titanium Alloys Surface Modification Technology for Antibacterial and Osteogenic Properties

Background: Titanium (Ti) and its alloys are potential metal materials in dental and orthopedic applications, due to their excellent mechanical properties and biocompatibility. Despite these properties, revision surgery is painful for millions of patients and may cause secondary injury, calling for a solution to this issue. Compared to antibiotics used in a clinical context, novel biomaterials display powerful application potential due to their stronger antibacterial activity, reduced drug resistance and excellent biocompatibility. Antibacterial ions have a crucial effect, particularly for nanostructured metals. Objective: This review focuses on the antibacterial functions and osteogenic properties of surface modification based on Ag, Zn, Cu and other nonmetallic ions. Methods: The first part of the review briefly describes the issues with bacterial infection of Ti implants. The methods of surface modification are then introduced in detail. Lastly, other strategies used to improve antibacterial and osteogenic properties are also provided. Conclusion: Although anti-infective research is valuable, there is still a gap present between theoretical strategies and those that are clinically implemented strategies. There is an urgent need to transform the findings of research into clinical applications.

Carbon Decorated Ni(OH)2 Nanoflakes on Ni Foam as a Binder-Free Cathode for Lithium–Oxygen Batteries

Herein, we report a binder-free, low-cost and high performance cathode for lithium-oxygen batteries based on carbon black BP2000 decorated Ni(OH)2 nanoflakes array on Ni foam. The Ni(OH)2 nanoflakes array is fabricated by hydrothermal treatment of Ni foam in acidic medium without nickel salt. The highly organized structure of Ni(OH)2 nanoflakes array provides a more uniform distribution of catalysts and discharge products, resulting in high capacity with a relatively stable cycling voltage profile. The cathode outputs a discharge capacity as high as 12400 mAh gcarbon −1 at 160 mA gcarbon −1, which is 244% higher than that of BP2000 decorated Ni foam electrode without Ni(OH)2 nanoflakes array. The cathode can sustain 100 cycles under a capacity limitation of 320 mAh gcarbon −1 with high energy efficiency (∼67%). Our work points out the key issues and suggests an effective method for the surface modification technology.

Nanostructured Titanium Alloys Surface Modification Technology for Antibacterial and Osteogenic Properties

Nanostructured Titanium Alloys Surface Modification Technology for Antibacterial and Osteogenic Properties

Reducing engine oil and fuel consumptions by multidimensional laser surface texturing on cylinder surface

• Proposed the multidimensional laser surface texturing (MLST) process, based on the engine motion characteristic. • Established hardware and software systems and optimized the parameters of MLST process. • The ablating position of each laser pulse is manipulated, and various depths of micro dimples are fabricated by controlling the repeat times of overlapped laser pulses. • Developed the post-process for MLST process, based on the finishing honing process to remove the recast bulges (RCB) induced by laser ablation. • Tested four schemes of cylinder liners (one prototype, three MLST) on a single cylinder diesel engine at rated power and speed. • One of MLST scheme reduced engine oil and fuel consumptions simultaneously. The optimization of cylinder surface topography draws immense amounts of researches, since it has far-reaching effects on engines’ overall performances. In order to promote the lubricity of ring/bore interface, the present study developed the multidimensional laser surface texturing (MLST) process, which fabricates controllable arrays of micro dimples on cylinder surface. The MLST process was achieved by a series of innovations, including its hardware and software systems, and optimization of process parameters and efficiency. A post-process was developed based on the finishing honing process to remove the recast bulges (RCB) induced by laser ablation. Additionally, the cylinder liners with different surface texturing schemes were bench tested on a single cylinder diesel engine. The experimental results indicated that near TDC (top dead center) region and piston skirt contacting region (SKIRT) were two high-impact regions for the technical efficiency of the MLST process. Benefiting from the reasonable optimization of oil distribution and enhanced hydrodynamic lubrication, the MLST process was able to reduce engine oil and fuel consumptions simultaneously. This paper provides a comprehensive introduction of equipment, pre- and post-process, and capacities of the newly developed surface modification technology.

Rapid Detection of Glucose on Nanostructured Gold Film Biosensor by Surface-Enhanced Raman Spectroscopy.

In this report, we summarized our development of biosensors for Rhodamine 6G and in vitro glucose detection based on surface-enhanced Raman scattering technology. For the detection of both Rhodamine 6G and in vitro glucose, a nature-patterned substrate with gold films over nanostructures (NPS-AuFON) was used as the surface-enhanced Raman scattering sensor platform. The enhancement factor was calculated at 9 × 107. In the processing of the substrate, cyclic voltammetry was used to form nano-gold particles under different conditions. The Rhodamine 6G and glucose detection were then achieved on this substrate. Furthermore, we combined the potentiostatic technique and electrochemical adsorption to best detect glucose in low concentrations. The glucose oxidation potential (100 mV) was used to capture glucose close to the surface of the NPS-AuFON. The quantitative detection of glucose in solution and in situ inspection were confirmed. Further, we determined that this surface modification technology can reach the goal of experiments set by the World Health Organization to judge whether or not a patient is a diabetic by detecting a glucose concentration of 11.1 mmol/L (mg/dL) at a minimum.

An investigation of the effect of warm laser shock peening on the surface modifications of [001]-oriented DD6 superalloy

Warm laser shock peening (WLSP) is a novel surface modification technology involving a combination of laser shock peening (LSP) and dynamic strain aging (DSA) technologies. Nickel-based single-crystal superalloy is one of the leading materials for aeroengine turbine blades. Hence, studying the surface modification effect of WLSP on [001]-oriented DD6 nickel-based single-crystal superalloy has a real significance in the aerospace field. Three experimental heating temperatures, 260 °C, 280 °C, and 300 °C, were selected in the vicinity of DD6 DSA temperature, and WLSP treatment was carried out on [001]-oriented DD6 specimens. Microstructure, FEM simulation of laser-induced compressive residual stress field, microhardness, and microstructural changes after the heat treatment of specimens were studied. The test results show that WLSP could generate plenty of stable dislocation structures in the impacted regions, and the effect of WLSP is positively correlated with the experimental temperature. Besides, both the WLSP-induced compressive residual stress and the microhardness in the impacted region tend to increase with the increase in WLSP temperature. The microstructure of a WLSP specimen varies at different annealing temperatures.

Surface Modification Technologies for Aerospace and Engineering Applications: Current Trends, Challenges and Future Prospects

Surface Modification Technologies for Aerospace and Engineering Applications: Current Trends, Challenges and Future Prospects

Hepatic and renal cellular cytotoxic effects of heparin-coated superparamagnetic Iron oxide nanoparticles

BackgroundSuperparamagnetic iron oxide (SPIO) nanoparticles have been widely used in several biomedical engineering in vivo. Although various surface modifications have been made to these non-biodegradable nanoparticles to make them more biocompatible, their toxic potential still remains a major concern.MethodIn this study, we newly developed unfractionated heparin (UFH)-coated and low molecular weight heparin (LMWH)-coated SPIO nanoparticles through surface modification engineering, which was compared with commercially available dextran-coated SPIO nanoparticles. Their toxicity such as cytotoxicity, single cell gel electrophoresis (SCGE) comet assay, intracellular reactive oxygen species (ROS) content and cellular apoptosis was evaluated to hepatic HepG2 and renal HK-2 cells.ResultsWhen UFH-, LMWH- or dextran-coated SPIO nanoparticles were applied, they did not affect the viability of HepG2 cell. However, HK-2 cells were more sensitive to dextran-coated SPIO nanoparticles than others. In genotoxicity assay using SCGE comet, DNA tail moment values in the groups treated with dextran- and LMWH-coated SPIO nanoparticles significantly increased. However, UFH-coated SPIO nanoparticles was only significantly lowing DNA tail moment value. In addition, UFH-coated SPIO nanoparticles had lower cytotoxicity in HepG2 and HK-2 cells compared to dextran-coated SPIO nanoparticles, especially in terms of apoptosis and intracellular ROS production.ConclusionsCollectively, it is possible that UFH- coated SPIO nanoparticles can be used as alternative negative contrast agents.

Selection of Casting Materials for Working Parts of Machines for The Forestry Sector

The article was created as a result of the work of the TECHMATSTRATEG 1 “Modern Material Technologies” Program as part of the project with the acronym INNOBIOLAS entitled “Development of innovative working elements of machines in the forestry sector and biomass processing based on high-energy surface modification technologies of the surface layer of cast elements”; agreement No. TECHMATSTRATEG1/348072/2/ NCBR/2017.

Direct cueing by pulsed-waterjet treated titanium on fibroblast, osteoblastic and human stem cells for prospective use in dental implants

Pulsed-waterjet (PWJ) technology holds potential for the biologically effective surface treatment of dental titanium implants. In addition to the proliferative response of in vitro models for gingiva (NIH/3T3s) and bone (Saos-2) cells, our study investigates the osteogenic potential of PWJ-treated titanium surfaces by employing human mesenchymal stem cells (hMSCs). The greatest proliferation of fibroblast NIH/3T3 and osteoblast-like Saos-2 cells was elicited on T1.76 and T4.83 treatment conditions, respectively. Morphological traits and the nuclear localization of an osteogenic reporter (OSX) indicate preferential osteogenic differentiation on the T2.43 condition. This work demonstrates the potential of PWJ technology for surface modification, supporting its technological translation as a cost-effective, environmentally friendly, and contaminant-free method to incorporate novel bioactive properties into titanium implants.

Investigation of pool boiling heat transfer on hydrophilic-hydrophobic mixed surface with micro-pillars using LBM

Surface modification technology by controlling the surface wettability or applying micro/nano-structures to enhance the boiling heat transfer performance has attracted a great deal of interest in recent years. Abundant experiments were performed to investigate the boiling processes on the modified surfaces, and lots of experimental data as well as reliable conclusions were obtained. With the advantages of saving costs and time, the numerical method has been a new reliable way to investigate the bubble dynamics and heat transfer during pool boiling processes on the modified heated surfaces. Pseudopotential LB model is capable of simulating the entire boiling processes including the bubble nucleation, and this model has been successfully applied to simulate the pool boiling processes on both the smooth surfaces and the hydrophilic-hydrophobic mixed surfaces with micro-pillars. However, the numerical simulations of the boiling processes on the mixed surfaces were still rare, and the influence of geometrical parameters of pillar structures of the mixed surface on boiling heat transfer performance was still unclear yet. Moreover, some of the conclusions in existing literature were inconsistent with those in others. Thus it's necessary to carry out more numerical and experimental researches to solve these problems. In this study, the MRT pseudopotential model coupled with phase-change model was applied to simulate the pool boiling processes on the hydrophilic-hydrophobic mixed surface textured with micro-pillars. Under different wall superheats, the bubble dynamics and heat transfer during boiling processes on the mixed surface with micro-pillars were compared to those on the smooth hydrophilic surface and the hydrophilic-hydrophobic mixed surface without micro-pillars. The heat transfer enhancement mechanism of the mixed surfaces was revealed and the influence of geometrical parameters of pillars, including pillar width and pillar number, on bubble dynamics and heat transfer performance during pool boiling processes was investigated in detail.

Synthesis of PEG-dendron for surface modification of pancreatic islets and suppression of the immune response.

Islet cell transplantation has been an effective method for the treatment of type 1 diabetes. The transplanted islets release insulin in response to changes in blood glucose levels. The clinical application of islet transplantation, however, has been hindered because of some critical problems including immune responses to grafted islets and side effects caused by overdosed immunosuppressive drugs. Herein, surface modification technology using poly(ethylene glycol) (PEG)-dendron was proposed to safeguard islets from the host immune system. PEG-dendron was synthesized by a divergent polymerization method and utilized to cover the islet antigen surface. Successful conjugation of PEG-dendron on the islet surface was achieved without affecting islet morphology, viability, and functionality at a concentration of 1.00%. Surface modification using PEG-dendron effectively prevented protein absorption and immune activation. Foremost, it improved the survival rate of islet grafts in vivo when combined with a low dose of immunosuppressive drugs. In conclusion, PEG-dendron is a potential candidate for the surface modification of pancreatic islets to mitigate immune responses after transplantation.

Surface Modification Technology for Automotive Rubber Parts

Surface Modification Technology for Automotive Rubber Parts