Surface Modification Techniques Research Articles

REVIEW OF LITERATURE ON NANOSCALE TOPOGRAPHIC MODIFICATION, MAGNETIC NANOPARTICLES, AND THEIR ROLES IN OSSEOINTEGRATION AND BONE TISSUE ENGINEERING

Here, we will review together the roles of nanoscale modification of titanium substrates and use of magnetic nanoparticles in osseointegration and bone tissue engineering. The technological advances in nanotechnology that has been achieved create new measures to increase the implants-biological systems for an optimal osseointegration through improving important cell-specific functions. We systematically review nanoscale surface modification techniques of titanium implants, covering their physicochemical properties, influence on cellular behaviors and clinical relevances. The report also lengthy discusses the clinical applicability of magnetic nanoparticles for drug and gene delivery systems, targeted cancer therapy as well bone tissue engineering regulting their intrinsic superparamagnetism properites, biocompatibility with other therapies etc. We present detailed review of these technologies and their potential applications in clinical settings.

A comparative characterization analysis of electrode materials for optimal deposition on copper by advancing electrical discharge coating

This research explores the efficiency of Electrical Discharge Coating (EDC) as an advanced surface modification technique using powder suspension, conventional electrodes, and 3D printed electrodes (3DPE), focusing on Ti6Al4V alloys. Conventional Ti electrodes resulted in 100% titanium content with a thickness of 110 µm, while the powder suspension coating was inadequate. The use of 3D printed electrodes showed promising results, with uniform deposition of 61.20 µm thickness and enhanced surface properties under 10 A current. Further analysis of 3D printed Ti6Al4V EDC revealed a higher Ti percentage of 44.20%, TiC formation of 84.17%, and enhanced microhardness with lower surface roughness. Thorough optimization of 3D printed electrode EDC has been undertaken. The study suggests the potential replacement of traditional electrodes such as powder metallurgy with 3D printed counterparts, advancing surface modification techniques and opening new avenues for materials engineering and manufacturing processes.

Effects of nanoceramic particle size and content on the wear resistance of micro-arc oxidation coatings for 2A12 aluminum alloy

The 2A12 aluminum alloy, renowned for its exceptional mechanical properties, encounters significant limitations in applications involving abrasive environments or frequent contact with other surfaces due to its inadequate wear resistance. This shortcoming substantially reduces the service life of components and escalate maintenance costs, highlighting the urgent need for advanced surface modification techniques. This study meticulously investigates the influence of nanoceramic particle size and content on the wear resistance of micro-arc oxidation (MAO) coatings, a surface modification technique renowned for forming dense, adherent ceramic layers on aluminum alloys. The systematic experimentation revealed that the incorporation of 150 nm α-Al2O3 nanoparticles into the MAO matrix achieves an optimal dispersion, leading to a substantial enhancement in wear resistance. The sample with a 5 g/L concentration of 150 nm α-Al2O3 nanoparticles doping in the MAO electrolyte demonstrated the lowest mass loss, underscoring its enhanced wear resistance. The enhanced microstructure, enriched with hard ceramic phases such as α-Al2O3 and mullite, plays a pivotal role in withstanding wear. Moreover, this study identified that an optimal balance of surface roughness and coating thickness is essential for achieving enhanced wear resistance. The findings of this research provide a strategy for the design of wear-resistant coatings tailored for high-performance applications across aerospace, automotive, and general engineering industries. By optimizing the particle size and concentration in MAO coatings, this study paves the way for the development of durable materials capable of thriving in demanding environments, thereby extending the service life and reducing maintenance requirements of components.

Understanding Boron Chemistry as the Surface Modification and Electrolyte Additive for Co‐Free Lithium‐Rich Layered Oxide

AbstractLithium‐rich layered oxide (LRLO) stands out as a highly promising cathode material for the next generation of Li‐ion batteries, owing to its exceptional lithium storage capacity. The absence of cobalt in LRLO's composition provides an additional advantage, enabling cost‐effective production and thereby improving the feasibility of large‐scale manufacturing. Despite these promising attributes, LRLO has encountered challenges related to poor cycling performance and severe voltage decay, impeding its practical application. In addressing these challenges, a surface modification technique involving lithium borate (LBO) is employed through a dry coating method. The LBO‐coated LRLO exhibits a uniform surface layer with a thickness of 15 nm. Furthermore, the performance of LBO‐coated LRLO in a full cell is synergistically enhanced when combined with lithium bis(oxalato)borate (LiBOB) as an electrolyte additive. A discharge capacity retention of 82% is achieved after 400 cycles at room temperature. These substantial improvements are attributed to the continual reaction between boron species on the LRLO cathode surface and PF6− anions in the electrolyte. This reaction generates BF4− and suppresses HF acid formation during the high voltage charging process, demonstrating LRLO's potential for practical implementation.

Environmental and economic impact assessment of hydrophobic treatment of cotton using low-pressure-low-temperature plasma

The purpose of this paper is to compare the environmental impact, using Life Cycle Assessment, and the total cost of two hydrophobic fluorocarbon treatment methods: a novel plasma surface modification technique and a traditional pad-dry-curing treatment of fabric. These two techniques have been chosen as two alternatives, with the pad-dry curing being a traditional liquid-based treatment and the plasma treatment a novel gas-based treatment. Such a comparison is a novel effort and will provide to the relevant industrial stakeholders an indication about the sustainability and the financial viability of the plasma treatment technique in comparison to the current state-of-the-art.The Life Cycle Inventory for both techniques has been compiled based on experiments performed at the Technical Textiles Research Centre, using lab scale equipment. The environmental impact has been assessed using the Environmental Footprint 3.0 method and is expressed in micro ecopoints (μPt). The findings have revealed that for plasma treatment (duration of 5 min using 13 cm3/min of C2F6), the environmental footprint is 47% lower than the conventional pad-dry-curing (8.95 μPt per 10 g of treated cotton compared to 18.9 μPt) and the total treatment cost is 81% lower (£1.03 per 10 g of treated cotton compared to £5.47 using pad-dry-curing). The most significant contributor to the environmental performance of the plasma treatment is the electricity consumption, thus a minimization of the treatment time without losing the functionality of the process, and the subsequent operating expenses, will lead to the optimal plasma treatment conditions.

Zwitterion assisted in-situ grain boundary coating on Li-rich cathode boosting electrochemical performance in Li-ion batteries

High-capacity and high-voltage Li-rich cathode materials are promising candidates for next-generation LIB cathodes due to their high energy density characteristics. However, they face challenges such as electrolyte side reactions at high voltages and slow kinetic properties. To overcome these challenges, this study proposed a one-pot Li2WO4 (LWO) grain boundary coating method. Additionally, a novel synthesis process utilizing zwitterions was introduced to uniformly position heavy tungsten on the surface of a cathode material. Through grain boundary coating, the cathode material was modified not only at the secondary particle level, but also between primary particles by filling grain boundaries with the coating compound. The synthesized LWO grain boundary coated Li-rich cathode exhibited significantly superior rate capability and cycle stability compared to the pristine material. Furthermore, it demonstrated a more stable cycling behavior after high-temperature storage than pristine counterpart. This study presents a primary particle surface modification technique through grain boundary coating and a one-pot synthesis process leveraging zwitterions as a new driving force, providing a new perspective for enhancing the performance of Li-rich cathode materials.

Multifunctional SiC nanowire aerogels with efficient electromagnetic wave absorption for applications in complex environments

In the digital age, with rapid advancements in electromagnetic (EM) technology, electromagnetic pollution has emerged as a significant concern. Traditional electromagnetic wave (EMW) absorption materials, however, are constrained by their limited application range, inadequate physicochemical stability, and inferior mechanical strength, hindering their further development and application. Consequently, there exists a demand for an EMW absorber that not only incorporates multiple functionalities but also retains essential physicochemical characteristics. In this context, this study introduces an ultralight (∼12 mg cm⁻³) and multifunctional SiC nanowire aerogel (SNWA), synthesized through a direct chemical vapor deposition (CVD) technique. The resulting SNWA demonstrates exceptional elasticity, outstanding mechanical durability, and high thermal stability at increased temperatures. Additionally, the enhanced SNWA shows improved hydrophobic properties, facilitating its use in highly humid conditions. The SNWA material also presents remarkable EMW absorption efficiency, with a minimum reflection loss of −50.6 dB and an effective absorption bandwidth of up to 7.7 GHz. The straightforward CVD synthesis and surface modification technique ensure the SNWA's durable and efficient performance in demanding environments.

Synthesis, characterization, and surface modification of degradable polar hydrophobic ionic polyurethane nanoparticles for the delivery of therapeutics to vascular tissue

Degradable polar hydrophobic ionic polyurethanes (D-PHI) are an emerging class of biomaterials with particular significance for blood-contacting applications due to their immunomodulatory effects and highly customizable block chemistry. In this manuscript, D-PHI polymer was formulated as a nanoparticle excipient for the first time by inverse emulsion polymerization. The nanoparticles were optimized with consideration of diameter, surface charge, size variability, and yield as a delivery vehicle for a custom vascular therapeutic peptide. A layer-by-layer (LBL) surface modification technique using poly-L-lysine was integrated within the nanoparticle design to optimize therapeutic loading efficiency. Solvent pH played a pivotal role in emulsion micelle formation, LBL polymer secondary structure, and the polymer functional group interactions critical for high therapeutic loading. The resulting nanoparticle platform met target size (200 ± 20 nm), polydispersity (<0.07), and storage stability standards, was nontoxic, and did not affect therapeutic peptide bioactivity in vitro. Surface-modified D-PHI nanoparticles can be reproducibly manufactured at low cost, generating a highly customizable excipient platform suitable for delivery of biomolecular therapeutics. These nanoparticles have potential applications in vascular drug delivery via localized infusion, drug eluting stents, and drug-coated angioplasty balloons. Statement of significanceNanoscale excipients have become critical in the delivery of many therapeutics to enhance drug stability and targeted biodistribution through careful design of nanoparticle composition, surface chemistry, and size. This manuscript describes the development of a nanoparticle excipient derived from an immunomodulatory degradable polar hydrophobic ionic polyurethane, in combination with a layer-by-layer surface modification approach utilizing poly-L-lysine, to transport a mimetic peptide targeting smooth muscle cell migration in vascular disease. The nanoparticle platform draws on the effect of pH to maximize drug loading and tailor particle properties. The low cost and easily reproducible system presents a highly customizable platform that can be adapted for therapeutic delivery across a wide range of clinical indications.

Histological and scanning electron microscopy investigation of the effects of titanium surface modifications on osseointegration in rabbits.

This study aimed to compare the novel Estaş Medical Anodization (EMA) surface treatment technique with the techniques commonly used in the literature and to examine their effects on osteointegration in the rabbit tibia. A total of 24 rabbits used in this study were divided into 3 groups, with 8 rabbits in each group. Using both tibias of all rabbits in the study, screws belonging to the control group were placed in the left tibia, and the right tibia belonging to the experimental group were placed. In the first 8 rabbits, a single experimental group in the right tibia were used; in the second 8 rabbits, 2 different experimental groups in the right tibia were used; and in the last 8 rabbits, 2 different experimental groups in the right tibia were used. Thus, 5 different experimental groups with 8 screws in each group and a separate control group were formed for each of them. EMA-treated surfaces were named 200-800 nm iris oxidation and 800-1200 nm gray oxidation according to the TiO2 layer thickness. Group 1 was implanted with mini-screws prepared with chemical etching+EMA iris oxidation, while group 2 was implanted with sandblasted, large-grit and acid-etched (SLA) mini screws treated with EMA gray oxidation. Group 3 was implanted with mini-screws treated with EMA gray oxidation, group 4 was implanted with mini-screws treated with chemical etching+micro-arc oxidation, and group 5 was implanted with mini-screws treated with chemical etching+EMA gray oxidation. The control group was implanted with mini-screws prepared with pure titanium. At the end of 6 weeks, osseointegration percentages were calculated and compared using histological and scanning electron microscope (SEM) analyses. The histological results confirmed the increase in osseointegration percentages in all experimental groups compared to those that received pure titanium implants (P values control group vs group 1=.005, control group vs group 2, 3, 4, 5=.001). The comparison between the groups revealed that the chemical etching+EMA gray oxidation modification technique (group 5) significantly increased osseointegration compared to the SLA+EMA gray oxidation technique (group 5 vs group 2 P=.016) and the chemical etching+EMA iris oxidation technique (group 5 vs group 1 Pp=.001). The EMA gray oxidation technique (group 3) significantly increased osseointegration compared to the chemical etching+EMA iris oxidation technique (group 1) (group 3 vs group 1 P=.043). The results of the SEM analysis showed that osseointegration was significantly increased in all experimental groups compared to that in the pure titanium (control) group (P values control group vs group 1, 2, 3=.001, control group vs Group 4,5=.006). The mean osseointegration percentage in the experimental groups was the highest in group 5, followed by group 4, group 3 and group 1 equally, and group 2. However, the differences among the experimental were not significant (group 1, group 2, group 3, group 4 vs group 5 P=.408). The EMA titanium surface modification techniques we developed significantly increased osseointegration compared to the pure titanium surface. The EMA gray oxidation technique seems to result in higher osseointegration rates than the EMA iris oxidation technique, and similar rates can be found with the SLA and chemical etching techniques. N/A.

Performance evaluation of surface treatment waste glass as aggregate in asphalt mixture

Surface modification is a crucial strategy for enhancing the pavement performance of waste glass hot mix asphalt (HMA) mixtures. This study conducts a comparative analysis of various surface modification techniques to pinpoint the key factors that influence the interfacial interaction between waste glass and asphalt. To assess the performance of asphalt mixtures containing surface-treated waste glass, the study employed methods such as Energy Dispersive X-ray Spectroscopy (EDS), boiling water tests, and contact angle measurements, which helped to quantify surface morphology and the effectiveness of different treatments. The evaluation also included assessments of water stability, dynamic stability, small beam bending, and anti-skid properties. Findings revealed that applying a silane coupling agent to the waste glass significantly enhanced adhesion with asphalt, resulting in markedly improved pavement performance. The study identified that incorporating surface-treated waste glass at an optimal proportion of 6 % within the asphalt mixture led to a 42.3 % increase in dynamic stability and a 38.6 % enhancement in anti-skid performance compared to standard mixtures. This research offers a comprehensive evaluation framework for surface modification techniques of waste glass, underscoring its potential to considerably improve road performance.

Enhancing the interfacial properties of recycled rubber aggregate mortars through surface modifications with graphene oxide coating

This study explores the potential application of waste rubber (WR) as sustainable recycled rubber aggregates (RRA) in the construction sector. A layer of graphene oxide (GO) was coated on RRA through multiple surface modification techniques, aiming to enhance the interfacial properties in RRA mortars. The C-S-H phases were first tailored through chemical synthesis to better understand the nucleation and growth of hydration products with the presence of GO. Subsequently, a 180 ± 10 nm-thick GO coating was attached to the RRA surface through surface treatment with sodium hydroxide solution, silane coupling agent, and GO suspension. In addition, the mechanical strength, damping performance, water absorption, chloride resistance, and microstructural properties of cement mortars prepared with RRA were further assessed. It was found that the GO coating significantly improves the bonding between RRA and the cementitious matrix due to its hydrophilicity and nucleation effects, which locally facilitate the cement hydration at interfaces. The cement mortars produced with surface-modified RRA exhibit promising high-damping characteristics, accompanied by improved durability and mechanical performance over those prepared with untreated RRA.

Micro-arc driven porous ZrO2 coating for tailoring surface properties of titanium for dental implants application

Titanium (Ti) is an ideal material for dental implants due to its excellent properties. However, corrosion and mechanical wear lead to Ti ions and particles release, triggering inflammatory responses and bone resorption. To overcome these challenges, surface modification techniques are used, including micro-arc oxidation (MAO). MAO creates adherent, porous coatings on Ti implants with diverse chemical compositions. In this context, zirconia element stands out in its wear and corrosion properties associated with low friction and chemical stability. Therefore, we investigated the impact of adding zirconium oxide (ZrO2) to Ti surfaces through MAO, aiming for improved electrochemical and mechanical properties. Additionally, the antimicrobial and modulatory potentials, cytocompatibility, and proteomic profile of surfaces were investigated. Ti discs were divided into four groups: machined – control (cpTi), treated by MAO with 0.04 M KOH – control (KOH), and two experimental groups incorporating ZrO2 at concentrations of 0.04 M and 0.08 M, composing the KOH@Zr4 and KOH@Zr8 groups. KOH@Zr8 showed higher surface porosity and roughness, even distribution of zirconia, formation of crystalline phases like ZrTiO4, and hydrophilicity. ZrO2 groups showed better mechanical performance including higher hardness values, lower wear area and mass loss, and higher friction coefficient under tribological conditions. The formation of a more compact oxide layer was observed, which favors the electrochemical stability of ZrO2 surfaces. Besides not inducing greater biofilm formation, ZrO2 surfaces reduced the load of pathogenic bacteria evidenced by the DNA-DNA checkerboard analysis. ZrO2 surfaces were cytocompatible with pre-osteoblastic cells. The saliva proteomic profile, evaluated by liquid chromatography coupled with tandem mass spectrometry, was slightly changed by zirconia, with more proteins adsorbed. KOH@Zr8 group notably absorbed proteins crucial for implant biological responses, like albumin and fibronectin. Incorporating ZrO2 improved the mechanical and electrochemical behavior of Ti surfaces, as well as modulated biofilm composition and provided suitable biological responses.

Co-delivery of siRNA and cisplatin via electrospun Nanofibrous membranes for synergistic treatment of malignant melanoma

Tumor recurrence and metastasis remain formidable challenges in clinical oncology. Although surgery is an effective treatment for early-stage solid tumors, residual cancer cells can lead to subsequent recurrence or metastasis. Conventional treatments for melanoma, such as anti-tumor medications and gene therapy, have distinct limitations. The rapid systemic distribution of anti-tumor drugs poses a significant challenge, often resulting in notable side effects and inadequate drug concentrations at the tumor site. Melanoma (MM), a deadly form of skin cancer, is known for its high mortality rate. In this study, we propose a novel strategy for treating MM by combining the controlled release of chemotherapeutic drugs encapsulated within Metal-Organic Frameworks (MOFs) and liposomes with gene therapy targeting Minichromosome Maintenance Proteins 4 (MCM4) using electrospinning and surface modification techniques. In vitro and in vivo results confirmed that this hierarchical membrane system can effectively deliver therapeutic MCM4 siRNA and release cisplatin to inhibit tumor growth. Furthermore, we demonstrated that MCM4 silencing promoted the sensitivity of melanoma cells to ferroptosis both in vitro and in vivo. The proposed strategy, by allowing for a controlled and sustained release of medication, could alleviate the challenges in drug delivery and aid in prevent tumor recurrence.

Influence of friction stir processing (FSP) on arc directed energy deposited 316L stainless steel: a corrosion science study

Friction stir processing (FSP) was employed as a post-printing surface modification technique to enhance surface properties of arc-directed energy deposited 316L austenitic stainless-steel parts. Corrosion properties and passivity of stir zone and base metal were investigated in 3.5 wt.% NaCl solution. Results reveal a gradual improvement in corrosion protection ability of formed passive film on the alloy's surface over time. Specifically, FSPed region exhibited superior passive behavior and uniform corrosion resistance compared to base metal. This improvement was attributed to a more homogeneous microstructure of stir zone, which hindered micro-galvanic coupling effect. However, it was observed that FSP-treatment did not effectively impede the propagation of pitting corrosion.

Improving Triethylamine-Sensing Performance of WO3 Nanoplates through In Situ Heterojunction Construction.

Surface engineering techniques can be used to develop high-performance gas sensing materials and advance the development of sensors. In this study, we improved the gas sensing performance of two-dimensional (2D) WO3 nanoplates by combining surface Zn modification and the in situ formation of ZnWO4/WO3 heterojunctions. Introducing Zn atoms by surface modification can reconstruct the atomic surface of 2D WO3 nanoplates, creating additional active sites. This allowed for the preparation of various types of ZnWO4/WO3 heterojunctions on the surface of the WO3 nanoplates, which improved the selectivity and sensitivity to the target gas triethylamine. The sensor exhibited good gas sensing performance for triethylamine even at low operating temperatures and strongly resisted humidity changes. The ZnWO4/WO3 material we prepared demonstrated a nearly threefold improvement in the triethylamine (TEA) response, with a gas sensing responsivity of 40.75 for 10 ppm of TEA at 250 °C. The sensor based on ZnWO4/WO3 has a limit of detection (LOD) for TEA of 200 ppb in practical measurements (its theoretical LOD is even as low as 31 ppb). The method of growing ZnWO4 on the surface of WO3 nanoplates using surface modification techniques to form surface heterojunctions differs from ordinary composites. The results suggest that the in situ construction of surface heterojunctions using surface engineering strategies, such as in situ modifying, is a practical approach to enhance the gas sensing properties and resistance to the humidity changes of metal oxide materials.

Synthesis, Characterization and Application of Advanced Antimicrobial Electrospun Polymers.

The aim of this work was to synthesize, characterize and apply advanced antimicrobial biocompatible electrospun polymers suitable for medical implants for surgical repairs. Injuries to the musculoskeletal system often necessitate surgical repair, but current treatments can still lead to high failure rates, such as 40% for the repair of rotator cuff tears. Therefore, there is an urgent need for the development of new biocompatible materials that can effectively support the repair of damaged tissues. Additionally, infections acquired during hospitalization, particularly those caused by antibiotic-resistant bacteria, result in more fatalities than AIDS, tuberculosis, and viral hepatitis combined. This underscores the critical necessity for the advancement of antimicrobial implants with specialized coatings capable of combating Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staphylococcus aureus (MSSA), two strains notoriously known for their antibiotic resistance. Therefore, we developed an antimicrobial coating incorporating nanoparticle mixtures using the sol-gel process and applied it to electrospun polycaprolactone (PCL) filaments, followed by thorough characterization by using spectroscopic (FTIR, Raman, NMR) microscopic (SEM and SEM-EDX), and tensile test. The results have shown that the integration of electro-spinning technology for yarn production, coupled with surface modification techniques, holds significant potential for creating antimicrobial materials suitable for medical implants for surgical repairs.

Study on the regulation of droplet motion behavior on superhydrophobic surfaces

Wettability properties of the surface is essential for controlling the dynamic sliding of droplets, thereby facilitating surface self-cleaning and drag reduction. This study makes use of chemical etching and surface modification techniques to prepare superhydrophobic surfaces with micro-nano pore structures on copper. This research examines and evaluates the chemical composition, surface morphology, and hydrophobic characteristics of superhydrophobic surfaces, also investigates the exhibited excellent superhydrophobic properties, a positive correlation observed between the concentration of the modifier solution and the surface’s hydrophobic strength. Droplets move in an accelerated fashion on superhydrophobic surfaces, and the total resistance to droplet sliding decreases as the surface hydrophobicity increases and the wall tilt angle decreases. During the motion of droplets, the fluctuation range of the receding angle is considerably greater than that of the advancing angle, thereby rendering the receding angle as the primary determinant factor for droplet movement, and as the hydrophobicity of the surface improves, the fluctuation extent of the droplet’s receding angle experiences a significant diminution. Droplet motion on superhydrophobic surfaces comprises both slipping and rolling behaviors, the increased hydrophobicity of the surface and the larger tilt angle facilitate droplet movement in a slipping mode on the surface, within the experimental parameters, the proportion of rolling distance to slipping distance varies from 35 % to 15 %. This study has revealed innovative regulatory approaches for modulating the moving behavior of liquids on microstructured surfaces, potentially enabling the development of superior functional surfaces for fluid drag reduction or droplet manipulation in the future.

The Role of Surface Energy and Wettability in Polymer-Based Drug Delivery Systems: Enhancing Bioadhesion and Drug Release Efficiency

Polymer-based drug delivery systems are pivotal in advancing the precision and efficacy of modern therapeutics. Among the key factors influencing these systems, surface energy and wettability are crucial in determining their interaction with biological tissues and drug release behavior. Surface energy, which governs the adhesive properties of the polymers, plays a significant role in bioadhesion—a critical aspect for drug delivery routes that require prolonged contact with biological surfaces, such as mucosal membranes. Wettability, the extent to which a polymer surface can be wetted by biological fluids, influences both drug loading efficiency and release kinetics. Hydrophilic polymers, characterized by high wettability, typically facilitate rapid drug release, whereas hydrophobic polymers, with low wettability, offer controlled, prolonged release profiles. Additionally, the balance between hydrophilicity and hydrophobicity is essential for optimizing drug-polymer interactions, particularly in systems designed for sustained or targeted drug delivery. Advances in surface modification techniques have enabled precise control over these parameters, allowing for the customization of polymers to meet specific therapeutic requirements. This review discusses the interplay between surface energy, wettability, and drug delivery performance, highlighting how these properties have been manipulated to enhance bioadhesion, drug retention, and release profiles. The review also addresses the challenges in designing polymer wettability, such as maintaining stability, scalability, and regulatory compliance. Finally, it explores emerging trends, including stimuli-responsive polymers and nanotechnology integration, which hold promise for the next generation of drug delivery systems that are more efficient, targeted, and patient-specific, than current systems.

A REVIEW ON THE MECHANICAL AND TRIBOLOGICAL PROPERTIES OF THERMALLY SPRAYED HYDROXYAPATITE COATINGS FOR BIOMEDICAL IMPLANT MATERIALS

In recent years, many different biomedical implants have been created for prolonged usage within the human body. The number of these implants has been steadily expanding. It is a common practice to use metallic bioimplants as substitutes when attempting to replace human body components in an anatomically acceptable manner. But the metallic bioimplant was mostly made biocompatible by putting a biocompatible coating on its surface and then using the right surface modification techniques. This was the primary method by which the biocompatibility of the bioimplant was achieved. Thermal spraying is a method that is frequently employed in surface modification treatments to modify metallic bioimplants. These methods can be found in the medical field. This is due to the adaptability of the thermal spraying method. Because of their capacity to respond and adapt to physiochemical circumstances, coatings that are based on hydroxyapatite (HAp) are the most popular type to be used in thermal spraying. This is due to the fact that HAp is a naturally occurring mineral. On the other hand, the majority of the HAp coatings are unsuccessful as a result of the coating’s weak mechanical qualities and insufficient adhesive strength. Supplying the coating in question with reinforcement in the form of hard particles and doing so in the appropriate proportions makes it feasible to alter the qualities of HAp-based coatings to fulfill a variety of requirements. This can be accomplished by providing the coating with reinforcement. The purpose of this inquiry was to deconstruct and analyze a variety of thermally sprayed (TS) coatings. These coatings were used to adhere HAp-based coatings on bioimplants. In addition, a detailed discussion is offered on how the reinforcements have an effect on the mechanical and biocompatible qualities of the coatings. In addition, we have discussed the difficulties associated with TS HAp coatings and their potential uses in the manufacturing of 3D biomedical implants through the utilization of cold spray (CS).

Ultrasonic Cavitation Erosion Behavior of GX40CrNiSi25-20 Cast Stainless Steel through Yb-YAG Surface Remelting.

Laser beam remelting is a relatively simple and highly effective technique for the physical modification of surfaces to improve resistance to cavitation erosion. In this study, we investigated the effect of laser remelting on the surface of cast stainless steel with 0.40% C, 25% Cr, 20% Ni, and 1.5% Si on cavitation erosion behavior in tap water. The investigation was conducted using a piezoceramic crystal vibrator apparatus. Base laser beam parameters were carefully selected to result in a defect-free surface (no porosity, material burn, cracks) with hardness capable of generating better resistance to cavitation erosion. The experimental results were compared with those of the reference material. Surface morphology and microstructure evolution after cavitation tests were analyzed using an optical metallographic microscope (OM), scanning electron microscope (SEM), and hardness tests to explore the mechanism of improving surface degradation resistance. The conducted research demonstrated that surfaces modified by laser remelting exhibit a 4.8-5.1 times greater increase in cavitation erosion resistance due to the homogenization of chemical composition and refinement of the microstructure, while maintaining the properties of the base material.