Iranian Journal of Materials Science and Engineering

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Titanium implants are one of the most durable and conventional orthopedic and dental implants. The goal of this research is to improve the bio-compatibility of these implants by implementing nano coating of titanium oxide nanotubes (TNT) to enhance bone graft on the implant surface, and reduction of wound healing duration and risk of implant surgery at the same time. For this purpose, the effects of dimension and atomic structure of titanium oxide nanotubes are examined on the surface properties and biological performance and tried to introduce an optimum status of this nano-tubular structure. TNTs were synthesized by anodizing method on the surface of titanium sheets. Dimensions of TNT can be controlled by anodizing process parameters. Heat treatment affects the atomic structure of TNTs. Contact angle measurement as one of the important surface properties was investigated on different dimensions and structures of TNTs, to study human blood's physical interaction with the implant surface. In addition, the quality and quantity of bone material sediment on the surface were examined by SBF test and SEM analysis. Finally, cell culture provided informative data on bone cells' response to these nanotubular coatings by analyzing MTT results and SEM photography of cells. As a result, the optimum dimension and atomic structure of TNTs were defined and the required process parameters were introduced to obtain this state. This setup can be used as an optimum state of TNT as a nano coating on titanium implant with orthopedic functions to enhance the cell adhesion and acquire the highest proliferation rate which means faster bone graft and shorter convalescence.
 

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This study was undertaken to investigate the influence of graphene nano sheets on the structural characteristics and dry sliding wear behaviour of Al-5Cu-1Mg aluminium alloy. The optimum amount of GNPs for proper grain refining was selected as 0.5 wt.%. T6 heat treatment was applied for all specimens before wear testing. Significant improvements in wear properties were obtained with the addition of GNPs combined with T6 heat treatment. Dry sliding wear performance of the alloy was examined in normal atmospheric conditions. The experimental results showed that the T6 heat treatment considerably improved the resistance of Al-5Cu-1Mg aluminium alloy to the dry sliding wear. The results showed that dry sliding wear performance of without T6 microstructure specimens was a lower value than that of with T6 specimens.
 

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Investigation the structural and magnetic properties of nanocrystalline Co₇₈Zr₁₇B₂Si₁W₂ alloy during melt spinning and annealing processes were the main goal of this study. In this regard, samples were prepared using vacuum induction melting, melt spinning and subsequent annealing. The specimens were evaluated using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM). Based on results, nanocrystalline Co₅Zr single phase with hard magnetic properties (Ms=29.5 emu/g and Hc=2.7 kOe) successfully formed during melt spinning process (at wheel speed of 40 m.s^-1). The coercivity value of rapid solidified sample increased to about 3.2 kOe during annealing process up to 400°C. However, more increasing in annealing temperature lead to the transformation of non-equilibrium magnetic Co₅Zr phase to stable Zr₂Co₁₁ phase, which has distractive effects on final magnetic properties.
 

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Several extensive researches are being carried out in the field of 3D printing. Polymer matrices, such as High-Density Polyethylene (HDPE), are less explored in particular on the microstructure and mechanical properties of HDPE composites developed via Fused Deposition Modelling (FDM) process. Very scarce amount of works is devoted to study HDPE’s reinforced with carbon nano-tubes (CNT’s) . In the present work, we report on the mechanical properties of  HDPE composites prepared via FDM process. Varying proportions of CNTs ( 0.5, 1, 1.5 and 2%) are used as reinforcements. It is found that increasing CNT content enhances impact and tensile strength, with HDPE/2.0%CNT outperforming pure HDPE by approximately 71.6% and 25.4%, respectively. HDPE/2.0%CNT composite also showed Young's modulus approximately 49.2% higher than pure HDPE. According to fracture analysis, pure HDPE failed near ductile, whereas composites failed brittle. CNTs occupy the free positions in the polymeric chains, and their tendency to restrict chain mobility causes HDPE to lose ductility and begin to behave brittle. The use of CNTs as reinforcement successfully improved the mechanical properties of HDPE.

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Graphene Nanoparticles (GNPs), an upshot of nanotechnology have attracted great interest in diverse research fields including dentistry for their unique properties. Graphene Nanoparticles are cytocompatible and when combined with other compounds, they possess improved synergistic antimicrobial and anti-adherence properties against oral pathogens. The cytotoxicity of graphene in the oral setting has been reported to be very limited in the scientific literature. Current applications of graphene include reinforcing Polymethylmethacrylate (PMMA) for the fabrication of dentures, improving properties of dental luting agents like glass ionomer cement, reinforcing restorative composites and ceramics, and improving osseointegration of titanium dental implants by coating with graphene. This paper reviews the nanoparticle ‘Graphene’ and its potential uses in the field of restorative dentistry.
 

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In this study, an epoxy-based nanocomposite reinforced with copper oxide-graphene oxide hybrid was investigated. Initially, the hybrid powder of CuO–GO with a weight ratio of 9:1 was prepared. The hybrid filler with different weight percentages ranging from 0.1–0.5 was used to reinforce the epoxy resin. The prepared samples were analyzed using XRD, FTIR, FESEM, TEM, and tensile testing. According to the XRD results and SEM images, the hybrid powder was successfully prepared, and the mechanical testing results showed an improvement in tensile strength in the composite samples. The best composite sample in terms of tensile strength was the one containing 0.3 wt% of hybrid reinforcement, which exhibited a 73% increase in strength compared to the neat resin sample.

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The present work deals with the effect of Multi-walled Carbon Nanotube (MWCNT) and functionalized (carboxyl and amine) MWCNT on the mechanical properties of the PAEK (Poly Aryl Ether Ketone) polymer composite. The MWCNT and functionalized (carboxyl and amine) MWCNT concentration varied as 0.25, 0.5 and 0.75 weight percentages. Compositeswere prepared by using a melt compounding method using a twin-screw extruder and all testing samples were prepared using an injection molding machine as per American Society for Testing and Materials (ASTM) standards. Samples were tested for tensile strength, impact strength, flexural strength, heat deflection temperature, hardness, and density. There is an increase in the tensile strength, impact strength, flexural strength, and heat deflection temperature, with percentage increase in filler loading up to 0.5 %, followed by decrease in it with higher filler loading. The increase is maximum for amine functionalized MWCNT.

 

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Fe₃O₄ nanoparticles (NPs) with a continuous and mesoporous silica (m-SiO₂) shell were synthesized using a one-step method, sourcing silica from rice husk ash (RHA). The rice husk was thermally treated to obtain ash, from which silica was extracted as sodium silicate and precipitated by pH reduction. This silica powder, combined with iron chloride salts, facilitated the synthesis of the core-shell NPs. Mint extract acted as a capping agent to prevent agglomeration, and CTAB (cetyltrimethylammonium bromide) was used to create the porous SiO₂ shell. X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) characterization investigated the structure, size, and shell formation. Coating integrity and suspension stability were assessed through Fourier transform infrared spectroscopy (FTIR) and dynamic light scattering (DLS). DLS analysis showed a relatively narrow particle size distribution with an average hydrodynamic size of 72.6 nm. Small-angle X-ray scattering (SAXS) provided insights into the meso- and nanoscale structure, while BET and nitrogen adsorption-desorption isotherms confirmed the mesoporous nature of the silica shell. Magnetization measurements showed superparamagnetic behavior, with specific magnetization values of 57.9 emu/g for Fe₃O₄ and 27.5 emu/g for Fe₃O₄@m-SiO₂. These results confirm the successful synthesis of superparamagnetic magnetite NPs with a mesoporous silica coating from RHA.
 

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Iron oxide nanoparticles has attracted extensively due to their supermagnetic properties, preferred in biomedicine because of their biocompatibility and potential nontoxicity to human beings. Synthesis of iron nanoparticles (FeNPs) was prepared with the help of ferric chloride and ferrous sulphate by using the coprecipitation method. The variation and combination of ferric and ferrous concentrations affect the physical and magnetic properties of iron oxide nanoparticles.  The effect of 0.1 M ferric and ferrous concentration on iron oxide nanoparticles studied separately and in combination. The obtained nanoparticles were characterized by Particle size, zeta potential, Ultraviolet (UV-visible), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscope (SEM), Thermal gravimetric analysis (TGA), and Vibrating-sample magnetometer (VSM) techniques. Particle size was below 200nm and zeta potential was within the limit for all the batches. UV visible spectra at 224 nm, and FTIR exhibit two peaks at 510 and 594 cm-1, indicating iron oxide NPs and XRD confirmed the crystalline nature of Fe. SEM showed a spherical shape for all batches. The use of a combination of ferric and ferrous is more effective than its individual use. TGA and VSM studies confirmed its magnetic properties.
 

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Drug-resistance among bacteria is a concerning issue in medical field. Silver nanoparticles (AgNPs) are one of the promising novel nano-antibiotics. In the present study, AgNPs were synthesized using cell-free extract of Acinetobacter sp. challenged with silver nitrate. Preliminary observations done using UV-Vis spectrophotometry at 420 nm. Complete reduction of silver ions to AgNPs was confirmed through cyclic voltammetry. Electron microscopy revealed formation of spherical shaped nanoparticles of size upto 20 nm. These AgNPs were furthr used to determine their effect on activity of various antibiotics against pathogenic bacteria such as Neisseria and Xanthomonas. Higher antibacterial activity of AgNPs was observed against Gram-negative bacteria. Enhanced antibacterial action of AgNPs was observed with selected beta-lactam antibiotics producing upto 3-fold increase in area of zone of inhibition. On exposure to AgNPs, the minimum inhibitory concentration and minimum bactericidal concentration of antibiotics were lowered by upto 2000 times indicating potential synergistic action of AgNPs. This study clearly signifies that the drug, proved to be inefficient due to bacterial resistance, could be made functional again in presence of AgNPs. This will help in development of novel antibacterial formulations containing antibiotics and nanoparticles to combat multiple drug-resistance in microorganisms.

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The Mn-Zn ferrite with a composition of Mn_0.25Mg_0.08Cu_0.25Zn_0.42Fe₂O₄ has been synthesized in this study using the chemical sol-gel technique at a pH of 7. The sample was prepared and subsequently annealed at a temperature of 700°C. The nanocrystalline ferrite samples were subjected to characterization using X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Thermogravimetry (TG), and Differential thermal analysis (DTA). The findings of these observations are delineated and deliberated. The sample's phase composition was verified using X-ray diffraction examination. The crystalline size was determined using Scherrer's formula and was observed to be within the range of 20-75 nm. Two notable stretching bands were seen in the FTIR spectra within the range of 400-650 cm^-1. The spinel structure of the produced nanoparticles was confirmed by these two bands. The magnetic characteristics of the powder were examined using a Vibrating Sample Magnetometer (VSM). The presence of M-H hysteresis loops suggests that the produced nanoparticles have superparamagnetic properties, as evidenced by their low coercive force, remanent magnetization, and saturation magnetization values.
 

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With increasing energy demand and depletion of fossil fuel resources, it is pertinent to explore the renewable and eco-friendly energy resource to meet global energy demand. Recently, perovskite solar cells (PSCs) have emerged as plausible candidates in the field of photovoltaics and considered as potential contender of silicon solar cells in the photovoltaic market owing to their superior optoelectronic properties, low-cost and high absorption coefficients. Despite intensive research, PSCs still suffer from efficiency, stability, and reproducibility issues. To address the concern, the charge transport material (CTM) particularly the electron transport materials (ETM) can play significant role in the development of efficient and stable perovskite devices. In the proposed research, we synthesized GO-Ag-TiO₂ ternary nanocomposite by facile hydrothermal approach as a potential electron transport layer (ETL) in a regular planar configuration-based PSC. The as synthesized sample was examined for morphological, structural, and optical properties using XRD, and UV-Vis spectroscopic techniques. XRD analysis confirmed the high crystallinity of prepared sample with no peak of impurity. The optimized GO-Ag-TiO₂ ETL exhibited superior PCE of 8.72% with J_sc of 14.98 mA.cm^-2 ,V_oc of 0.99 V, and a fill factor of 58.83%. Furthermore, the efficiency enhancement in comparison with reference device is observed which confirms the potential role of doped materials in enhancing photovoltaic performance by facilitating efficient charge transport and reduced recombination. Our research suggests a facile route to synthesize a low-cost ETM beneficial for the commercialization of future perovskite devices.
 

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Researchers are increasingly focusing on green synthesis methods for silver nanoparticles due to their cost-effectiveness and reduced environmental impact. In this study, we utilized an edible bird's nest (EBN), a valuable economic resource, as the primary material for synthesizing silver nanoparticles using only water as the solvent. Metabolite profiling of the EBN extract was conducted using LC-QTOF-MS in positive mode (ESI+), revealing the presence of lipids, glycosides, peptides, polysaccharides, and disaccharides. Upon the addition of silver nitrate to the aqueous EBN extract, noticeable color changes from transparent to brown indicated the successful formation of AgNPs. Subsequent characterization of these silver nanoparticles involved UV-Visible spectroscopy, which revealed an absorption peak at 421 nm. Further characterization was carried out using FESEM, ATR-FTIR spectroscopy, and EDX analysis. The involvement of phenolic agents, proteins, and amino acids in reducing the silver particles was confirmed. The synthesized nanoparticles exhibited a spherical shape, and a particle size ranging from 10 to 20 nm. The presence of elemental silver was confirmed by a strong, intense peak around 3 keV in the EDX spectrum. To assess their potential, the antibacterial properties of the silver nanoparticles against Escherichia coli and Staphylococcus aureus were evaluated using the agar diffusion method.
 

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Hybrid photocatalysts, comprising both inorganic and organic polymeric components, are the most promising photocatalysts for the degradation of organic contaminants. The nanocomposite, Titania-Polyaniline (TiO₂-PANI) was synthesized using the chemical oxidative polymerization method. Various characterization techniques were employed to assess the properties of the catalysts. The ultraviolet diffuse reflectance spectroscopy (UV-DRS) analysis revealed that the TiO₂ absorbs only UV light while the TiO₂-PANI nanocomposite absorbs light from both UV and visible regions. The X-ray diffraction (XRD) results confirmed the presence of TiO₂ (anatase) in both TiO₂ nanoparticles and TiO₂-PANI (Titania-Polyaniline)  nanocomposite. The phases of the catalysts were verified through Raman, TEM, and SAED techniques where all results are in good agreement with each other. The average crystallite size of TiO₂ nanoparticle and TiO₂-PANI nanocomposite were 13.87 and 10.76 nm. The thermal stability of the catalysts was assessed by the Thermal gravimetric analysis (TGA) technique. The order of the thermal stability is TiO₂ > TiO₂-PANI > PANI.  The crystal lattice characteristics were confirmed using Transmission electron microscopy (TEM). The surface area measurements were confirmed from the Brunauer-Emmett-Teller (BET) study and were employed for the evaluation of the photocatalytic efficiency of both, TiO₂ nanoparticles and TiO₂-PANI nanocomposite catalysts. The energy dispersive spectroscopy (EDS) study was employed for elemental detection of the fabricated materials. While Raman spectroscopy was employed for the chemical structure and the phase characteristics of the materials. The standard conditions for the degradation of the CF dye were 8 g/L of catalyst dosage, 20 mg/L of dye concentration, and a pH of 7. The TiO₂-PANI nanocomposite exhibited superior efficiency as compared to pure TiO₂ nanoparticles, achieving almost 100 % degradation in just 40 minutes.  

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Silver/polyvinyl alcohol (Ag/PVA) nanocomposites were fabricated via an electrochemical method. Silver nanoparticles (AgNPs) with varying grain sizes were directly synthesized within PVA polymer matrices at deposition times of 15, 30, 45, 60, and 120 minutes. The integration of AgNPs within the PVA matrix was confirmed through Transmission Electron Microscopy (TEM) and optical absorbance measurements. X-ray Diffraction (XRD) analysis demonstrated the face-centered cubic structure of AgNPs. Furthermore, these prepared nanocomposites exhibited significant antibacterial properties against Bacillus subtilis and Pseudomonas pneumonia, as well as antifungal activity against Alternaria alternata. Remarkably, the AgNPs/PVA nanocomposite exhibited outstanding antifungal efficiency, resulting in an impressive inhibition zone of up to 47 mm.
 

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Biogenic synthesis of papain-conjugated copper metallic Nanoparticles and their antibacterial and antifungal activities Papain metallic conjugated nanoparticles (Papain-CuNPs) were synthesised using Papain and CuSO4.5H₂O. Papain-CuNPs were characterized using UV-visible spectroscopy, FT-IR, HR-TEM, XRD, FE-SEM, zeta potential, and a zeta sizer. The antibacterial activity of papain-CuNPs against human infectious microorganisms (Citrobacter spp, Pseudomonas aeruginosa and Candida albicans) was investigated. The mechanism of action of papain-CuNPs was evaluated using FE-SEM and HRTM. UV spectroscopy confirmed the plasma resonance (SPR) at 679 nm, which indicated the formation of papain-CuNPs. The FT-IR spectrum absorbance peaks at 3927, 3865, 3842, 3363, 2978, and 2900 cm^-1 indicate the presence of O-H and N-H of the secondary amine, and peaks at 1643 and 1572 cm^-1 represent C=O functional groups in Papain-CuNPs. EDAX analysis confirmed the presence of copper in the papain-CuNPs. The zeta potential (-42.6 mV) and zeta size (99.66 d. nm) confirmed the stability and size of the nanoparticles. XRD confirmed the crystalline nature of the papain-CuNPs. FE-SEM and HRTM showed an oval structure, and the nano particles' 16.71244–34.84793 nm. The synthesized papain-NPs showed significant antibacterial activity against clinical P. aeruginosa (15 mm). MIC 125 µg/ml) showed bactericidal activity against P. aeruginosa and the mechanism of action of Papain-NPs was confirmed using an electron microscope by observing cell damage and cell shrinking. Papain-CuNPs have significant antibacterial activity and are thus used in the treatment of P. aeruginosa infections

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Abstract
The power line insulators are permanently exposed to various environmental pollutants such as dust and fine particles. This may lead to flashovers and therefore widespread power blackouts and heavy economic damage. One way to overcome this problem is to make the insulator surface superhydrophobic. In this research, the superhydrophobic properties of the insulators were improved by applying room-temperature cured composite coatings consisting of epoxy and hydrophobic nano-silica particles. Either octadecyl trichlorosilane (ODTS) or hexamethyldisilazane (HMDS) was used to coat the silica nanoparticles and make them hydrophobic. Then, the hydrophobic silica was added to a mixture of epoxy resin and hardener. The suspension was applied on the surfaces of a commercial porcelain insulator and cold cured at ambient temperature. The coating increased the water contact angle from 50° to 149°. Even after 244 h exposure to the UV light, the samples preserved their hydrophobic properties. The adhesion of the coating was rated as 4B according to the ASTM D3359 standard. The coating decreased the leakage current by 40% and increased the breakdown voltage by 86% compared to the uncoated sample and showed promise for making power line insulators self-cleaning.