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In this study, the hydrophobic modification of coal gasification fly ash (FA) was investigated given the adverse effects of surface hydrophilic structures on the material field. The surface of FA was modified using stearic acid (SA), which successfully altered its hydrophilic structure. When the contact angle of S-FA increased from 23.4° to 127.2°, the activation index increased from 0 to 0.98, the oil absorption decreased from 0.564 g/g to 0.510 g/g, and the BET-specific surface area decreased from 13.973 m2/g to 3.218 m2/g. The failure temperature of SA on the surface of S-FA was 210 °C. The adsorption mechanism of FA was analyzed using density functional theory (DFT) and molecular dynamics (MD). The adsorption of water molecules by FA involved both chemical and physical adsorption, with active adsorption sites for Al, Fe, and Si. The adsorbed water molecules on the surface of FA formed hydrogen bonds with a bond length of 1.5–2.5 Å, leading to agglomeration. In addition, the long alkyl chain in SA mainly relied on the central carbon atom in the (-CH3) structure to obtain electrons in different directions from the H atoms in space, increasing the Coulomb repulsion with the O atoms in the water molecule and thereby achieving the hydrophobic effect. In the temperature range of 298 K to 358 K, the combination of FA and SA became stronger as the temperature increased. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, the hydrophobic modification of coal gasification fly ash (FA) was investigated given the adverse effects of surface hydrophilic structures on the material field. The surface of FA was modified using stearic acid (SA), which successfully altered its hydrophilic structure. When the contact angle of S-FA increased from 23.4° to 127.2°, the activation index increased from 0 to 0.98, the oil absorption decreased from 0.564 g/g to 0.510 g/g, and the BET-specific surface area decreased from 13.973 m2/g to 3.218 m2/g. The failure temperature of SA on the surface of S-FA was 210 °C. The adsorption mechanism of FA was analyzed using density functional theory (DFT) and molecular dynamics (MD). The adsorption of water molecules by FA involved both chemical and physical adsorption, with active adsorption sites for Al, Fe, and Si. The adsorbed water molecules on the surface of FA formed hydrogen bonds with a bond length of 1.5–2.5 Å, leading to agglomeration. In addition, the long alkyl chain in SA mainly relied on the central carbon atom in the (-CH3) structure to obtain electrons in different directions from the H atoms in space, increasing the Coulomb repulsion with the O atoms in the water molecule and thereby achieving the hydrophobic effect. In the temperature range of 298 K to 358 K, the combination of FA and SA became stronger as the temperature increased.

Photocatalysis technology based on solar-powered semiconductors is widely recognized as a promising approach for achieving eco-friendly, secure, and sustainable degradation of organic contaminants. Nevertheless, conventional photocatalysts exhibit drawbacks such as a wide bandgap, and rapid recombination of photoinduced electron/hole pairs, in addition to complicated separation and recovery procedures. In this research, we cultivated BiOBr in situ on the surface of copper foam to fabricate a functional photocatalyst (denoted as BiOBr/Cu foam), which was subsequently employed for the photodegradation of Methylene Blue. Based on photodegradation experiments, the 0.3 BiOBr/Cu foam demonstrates superior photocatalytic efficacy compared to other photocatalysts under solar light irradiation. Furthermore, its ease of separation from the solution enhances its potential for reuse. The analysis of charge transfer revealed that the copper foam functions as an effective electron scavenger within the BiOBr/Cu foam, thereby facilitating charge separation and the generation of photo-induced holes. This phenomenon contributes to a significantly enhanced production of hydroxyl radicals. This study provides a valuable perspective on the design and synthesis of photocatalysts with heightened practicality, employing a conductive substrate.

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Li-rich materials have become one of the most promising cathode candidates for next-generation lithium-ion battery systems due to their high capacity and operating voltage. Conventional O3-type Li-rich materials undergo a structural transition from a layered to a spinel phase during cycling, leading to the degradation in their electrochemical performance, especially in terms of their voltage decay. The oxygen atoms comprising the structure of O2-type Li-rich materials are stacked in the ABAC configuration, which can effectively suppress these harmful phase transitions. However, O2-type Li-rich materials are metastable structures and can only be synthesized via the means of complex ion exchange methods. In addition, the surface of the material is susceptible to side reactions with the electrolyte when charged to high voltages. Here, we explored the optimal conditions for the synthesis of O2-type Li[Li0.25Ni0.1Co0.05Mn0.6]O2 (LLNCM) in more detail by preparing the precursors using the sol-gel method. Meanwhile, the modification of the material's surface via low-temperature hydrolysis of aluminum isopropoxide has been proposed for the first time in this study to avoid the damage of metastable materials by the high-temperature coating process. The surface-modified materials prepared under optimal conditions exhibited an excellent electrochemical performance, indicating that a highly stable O2-type bulk phase structure with effective surface modification is a potential way to promote the commercial applications of Li-rich cathode materials. [ABSTRACT FROM AUTHOR]

In this work, a novel adsorbent for the removal of hexavalent chromium (Cr(VI)) in aqueous solution was successfully prepared by altering the 2D Ti 3 C 2 /chitosan composite with disodium ethylenediaminetetraacetate (EDTA·2Na) agent. The successful surface loading of chitosan on Ti 3 C 2 was demonstrated by various characterization methods, including scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The adsorption of Cr(VI) by Ti 3 C 2 -based composite under various circumstances was evaluated using batch adsorption experiments. The adsorption performance of the optimal sample for Cr(VI) was investigated in detail through different influencing factors, and the adsorption process was analyzed by adsorption kinetics and isotherm model. In addition, XPS analysis of adsorbents before and after adsorption showed that some Cr(VI) was reduced to Cr(III) during the whole process, which was conducive to reducing the biological toxicity of Cr(VI). The mechanism analysis showed that the adsorption was mainly electrostatic physical adsorption, supplemented by chemical reduction adsorption. Finally, through the regeneration cycle experiment, it was found that the adsorption rate of Cr(VI) remained above 80% after six repeated adsorptions, indicating that the composite material had good stability and might have certain practical application value in the treatment of Cr(VI)-containing wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

Li-rich materials have become one of the most promising cathode candidates for next-generation lithium-ion battery systems due to their high capacity and operating voltage. Conventional O3-type Li-rich materials undergo a structural transition from a layered to a spinel phase during cycling, leading to the degradation in their electrochemical performance, especially in terms of their voltage decay. The oxygen atoms comprising the structure of O2-type Li-rich materials are stacked in the ABAC configuration, which can effectively suppress these harmful phase transitions. However, O2-type Li-rich materials are metastable structures and can only be synthesized via the means of complex ion exchange methods. In addition, the surface of the material is susceptible to side reactions with the electrolyte when charged to high voltages. Here, we explored the optimal conditions for the synthesis of O2-type Li[Li0.25Ni0.1Co0.05Mn0.6]O2 (LLNCM) in more detail by preparing the precursors using the sol-gel method. Meanwhile, the modification of the material’s surface via low-temperature hydrolysis of aluminum isopropoxide has been proposed for the first time in this study to avoid the damage of metastable materials by the high-temperature coating process. The surface-modified materials prepared under optimal conditions exhibited an excellent electrochemical performance, indicating that a highly stable O2-type bulk phase structure with effective surface modification is a potential way to promote the commercial applications of Li-rich cathode materials.

Electrocatalysts for catalyzing oxygen reduction reactions at variable pH conditions are essential for energy conversion and storage. Herein, Fe@FeCoZn–CN electrocatalysts were prepared with internal and external doping approach. The Fe@FeCoZn–CN electrocatalyst exhibits a desirable ORR performance in both acid and alkaline electrolytes. Specifically, the half-wave potential (E 1/2) of Fe@FeCoZn–CN electrocatalyst is 0.890 V which far beyond Pt/C electrocatalyst (0.839 V) in alkaline electrolyte. In addition, Fe@FeCoZn–CN electrocatalyst also exhibits improved ORR activity (E 1/2 = 0.801 V) compared to Pt/C (0.797 V) electrocatalysts in acidic electrolytes. What's exciting is that the rechargeable ZABs based on Fe@FeCoZn–CN electrocatalysts exhibit an impressive performance with a favorable open-circuit potential of 1.517 V and a promising specific capacity is 833.7 mA h g z n − 1 , good charge/discharge cycle stability. The remarkable ORR catalytic performance of Fe@FeCoZn–CN electrocatalysts can be traced to the internal doping of metals which prevent excessive metal aggregation and surface modified which can increase the metal loading to expose more active sites. Metal-organic frameworks with internal doping and surface modification properties were successfully constructed, which exhibited favorable electrocatalytic performance as electrocatalysts under alkaline and acidic conditions, and were successfully applied to Zn-air batteries. [Display omitted] • Internal doping can effectively prevent the aggregation of metals. • Surface modified can increase metal loading and expose more active sites. • The electrocatalyst exhibits an impressive ORR in both alkaline and acidic media. [ABSTRACT FROM AUTHOR]

In this article, a self-breakdown repetitive gap switch based on the graphite electrodes with surface modified by TiC is investigated to improve the scattering of the breakdown voltage. The self-breakdown repetitive gap switch was experimentally studied with the graphite electrodes and two kinds of TiC modified graphite electrodes (hereinafter referred to as TiC-I electrodes and TiC-II electrodes). Results show that the scatterings of the breakdown voltages of the graphite, TiC-I and TiC-II electrodes were 2.49%, 1.80%, and 1.54%, respectively. Compared with the graphite electrodes, the mass losses of TiC-I and TiC-II electrodes are reduced by 50% and 68%. The influence of electrode surface morphology on the switch stability is analyzed based on the mechanism of switch conduction process. Compared with the graphite electrodes, the electric field amplification coefficients of TiC-I and TiC-II electrodes are more evenly distributed, which leads to the more evenly distributed field emission current density. Thus, the breakdown areas of TiC-I and TiC-II electrodes are smaller and the gas breakdown processes are more stable than those of the graphite electrodes, resulting in smaller scattering of the breakdown voltage. The method that decreases the scattering of the breakdown voltage and reduces the mass loss of the electrodes by modifying graphite electrodes surface can greatly improve the stability of the switch, which is of significance to the application of the switch in the compact, long time stable operation of high-power pulse power devices. [ABSTRACT FROM AUTHOR]

The interface adhesive properties and mechanical properties of shape memory alloy composites were experimentally investigated. The two diameters of shape memory alloy (SMA) wire were surface modified by sandpaper, acid corrosion and alkali corrosion. Pull-out tests of single fiber and tensile tests of composite laminates were carried out. The results show that SMA after acid corrosion is the most effective to improve interface adhesive properties. With the increase of SMA diameter, the contact area between the matrix and SMA increases, so the degree of interfacial bonding is more obvious. The mechanical properties of SMA-modified composite laminates polished by sandpaper have been fully improved. SMA plays a full role in tensile resistance as long as the interface adhesive strength is large enough. Scanning electron microscopy shows that the surface roughness of the SMA wire treated in H2SO4 is more obvious than the other two. [ABSTRACT FROM AUTHOR]

Abstract Solution-processed colloidal quantum dot solar cells (CQDSCs) is a promising candidate for new generation solar cells. To obtain stable and high performance lead sulfide (PbS)-based CQDSCs, high carrier mobility and low non-radiative recombination center density in the PbS CQDs active layer are required. In order to effectively improve the carrier mobility in PbS CQDs layer of CQDSCs, butylamine (BTA)-modified graphene oxide (BTA@GO) is first utilized in PbS-PbX2 (X = I−, Br−) CQDs ink to deposit the active layer of CQDSCs through one-step spin-coating method. Such surface treatment of GO dramatically upholds the intrinsic superior hole transfer peculiarity of GO and attenuates the hydrophilicity of GO in order to allow for its good dispersibility in ink solvent. The introduction of BTA@GO in CQDs layer can build up a bulk nano-heterojunction architecture, which provides a smooth charge carrier transport channel in turn improves the carrier mobility and conductivity, extends the carriers lifetime and reduces the trap density of PbS-PbX2 CQDs film. Finally, the BTA@GO/PbS-PbX2 hybrid CQDs film-based relatively large-area (0.35 cm2) CQDSCs shows a champion power conversion efficiency of 11.7% which is increased by 23.1% compared with the control device.

Aluminum nitride (AlN) ceramic is a material with many excellent properties, such as high thermal conductivity and outstanding electrical insulation, but the required raw powders are easily hydrolyzed that affects the performance after sintering. Therefore, surface modification of AlN powder is essential. In this study, the raw AlN powders were treated in an ethanol with silicic acid (H 2 SiO 3) by heating and stirring at 80 °C. The treated powders will not be hydrolyzed under high temperature and stirring, which was confirmed by pH measurement (pH), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Transmission Electron Microscope (TEM) etc. methods. The XRD spectra proves that the characteristic crystalline peaks of the treated AlN powders after impregnating warm aqueous solution over twenty days are still the same as those of the raw AlN powders. The pH value of the suspension with treated AlN powders remains constant at 7.0–8.0 in 80 °C/90 °C water for 72 h. FTIR and TEM analysis shows that a 3–18 nm protective layer of Si–O–Si wrapped on the surface of the AlN powders. These results directly indicate that the AlN powders treated with H 2 SiO 3 have good hydrolysis resistance. Moreover, the relative density and thermal conductivity of the ceramics sintered by the treated AlN powders can reach 97.21% and 144.505 w/(m· K), respectively. [ABSTRACT FROM AUTHOR]

Residues oil from oil slick treatment on the water surface cause chronic damage to the environment. These thin oil slicks were labeled with fluorescent. Adsorption characteristics of the modified polypropylene (PP) non-woven fabric PP-GMA-OA/SS were studied. The introduction of hydrophilic groups on the surface of oleophilic materials can accelerate the adsorption of thin oil slicks and produces two strengthening effects. Hydrophilicity is used to induce water molecules to carry oil slicks approach to the fabrics. Hydrophobicity of the fabric is used to quickly capture the oil. Through a method of fluorescence image processing, thin oil slicks were quantified based on integrated optical density (IOD) values. The method verified the rapid adsorption performance of modified PP non-woven fabrics on residual oil slicks based on hydrophilic induction and hydrophobic capture. The material has considerable adsorption capacity and is economical as a supplement material to thin oil slick adsorption. [ABSTRACT FROM AUTHOR]

AIM: To investigate whether hydroxyapatite (HAp) coating can improve keratoprosthesis (KPro) implant biointegration, ultimately to decrease the risk of implant-associated complications. METHODS: The modified titanium implant was designed and prepared for artificial cornea. The titanium implant was treated with sandblasting and hydroxyapatite coating by acid-base two-step method. Surface was analyzed by scanning electron microscopy (SEM), KPro implants coated with HAp and KPro implant sandblasted were implanted in rabbits. Tissue adhesion to the implant was assessed and compared to an unmodified implant by histopathology (HE), transmission electron microscopy (TEM) and SEM. RESULTS: SEM demonstrated successful deposition of HAp on titanium implant sandblasted (HA/SB-Ti). The hydroxyapatite coatings caused enhancement of keratocyte proliferation compared with unmodified implant surfaces. HAp coating significantly increased adhesion forces. HAp coating of implants reduced the inflammatory response around the KPro implants in vivo. CONCLUSION: HAp-coated surfaces for use in titanium KPro implant greatly enhanced adherence of the titanium KPro implant in the rabbit cornea.

Highlights: Butylamine-modified graphene oxide (BTA@GO) is first utilized in PbS colloidal quantum dots (CQDs) ink to deposit the active layer of colloidal quantum dot solar cells (CQDSCs). The BTA@GO improves the carrier transfer rate in the CQDs active layer and 11.7% conversion efficiency is achieved.Solution-processed colloidal quantum dot solar cells (CQDSCs) is a promising candidate for new generation solar cells. To obtain stable and high performance lead sulfide (PbS)-based CQDSCs, high carrier mobility and low non-radiative recombination center density in the PbS CQDs active layer are required. In order to effectively improve the carrier mobility in PbS CQDs layer of CQDSCs, butylamine (BTA)-modified graphene oxide (BTA@GO) is first utilized in PbS-PbX2 (X = I−, Br−) CQDs ink to deposit the active layer of CQDSCs through one-step spin-coating method. Such surface treatment of GO dramatically upholds the intrinsic superior hole transfer peculiarity of GO and attenuates the hydrophilicity of GO in order to allow for its good dispersibility in ink solvent. The introduction of BTA@GO in CQDs layer can build up a bulk nano-heterojunction architecture, which provides a smooth charge carrier transport channel in turn improves the carrier mobility and conductivity, extends the carriers lifetime and reduces the trap density of PbS-PbX2 CQDs film. Finally, the BTA@GO/PbS-PbX2 hybrid CQDs film-based relatively large-area (0.35 cm2) CQDSCs shows a champion power conversion efficiency of 11.7% which is increased by 23.1% compared with the control device. [ABSTRACT FROM AUTHOR]

Photocatalysis technology based on solar-powered semiconductors is widely recognized as a promising approach for achieving eco-friendly, secure, and sustainable degradation of organic contaminants. Nevertheless, conventional photocatalysts exhibit drawbacks such as a wide bandgap, and rapid recombination of photoinduced electron/hole pairs, in addition to complicated separation and recovery procedures. In this research, we cultivated BiOBr in situ on the surface of copper foam to fabricate a functional photocatalyst (denoted as BiOBr/Cu foam), which was subsequently employed for the photodegradation of Methylene Blue. Based on photodegradation experiments, the 0.3 BiOBr/Cu foam demonstrates superior photocatalytic efficacy compared to other photocatalysts under solar light irradiation. Furthermore, its ease of separation from the solution enhances its potential for reuse. The analysis of charge transfer revealed that the copper foam functions as an effective electron scavenger within the BiOBr/Cu foam, thereby facilitating charge separation and the generation of photo-induced holes. This phenomenon contributes to a significantly enhanced production of hydroxyl radicals. This study provides a valuable perspective on the design and synthesis of photocatalysts with heightened practicality, employing a conductive substrate., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper., (© 2024 The Authors.)

Objective: To evaluate the effect of Nd-Fe-B magnets coated with Ni, Ti N and Ni-Ti N composite coatings on the bile corrosion through the in vitro immersion method, and provide a surface modification scheme for the clinical application of magnetic compression technique in biliary reconstruction. Methods: The bile of clinical patients was collected, and the magnets were immersed at38 ℃ in vitro. The weight of magnets was periodically weighed and the soaking solution was replaced to measure the iron ion concentration of the soaking solution. After 30 days of immersion, the weight loss rate of each group of magnets were calculated, and the surface structure of magnets were observed by scanning electron microscopy. Results: After 30 days of bile soaking, the weight loss rates of magnets of bare magnet, nickel plating, titanium nitride coating and nickel-titanium nitride composite coating were 0.57%, 0.35%,0.34%, and 0.19%, respectively. The concentration of iron in the soaking solution is different in each time points. Electron microscopy showed that the surface of each group of magnets showed different degrees of corrosion spots after immersion, and the coating appeared to fall off. Conclusions: The corrosion resistance of NdFeB magnets after surface modification of nickel-titanium nitride composite coating was significantly better than that of pure nickel coating and titanium nitride coating. [ABSTRACT FROM AUTHOR]

Abstract In recent years, the rapid development of portable equipment and flexible wearable devices urgently requires supercapacitor electrode material with high volumetric capacitance. Ti 3 C 2 T x , a member of MXenes family, is one of the most promising supercapacitor electrode material candidates. However, how to further enhance the volumetric capacitance of the Ti 3 C 2 T x is still a great challenge at present. In this paper, a simple and eco-friendly method is presented by preparing flexible Ti 3 C 2 T x supercapacitor electrode using self-assembly of few-layer Ti 3 C 2 T x followed by alkalinizing and annealing treatment. The alkalinized and annealed Ti 3 C 2 T x film (denoted as ak-Ti 3 C 2 T x film-A) exhibits an ultrahigh volumetric capacitance of 1805 F cm−3 at 1 A g−1, and an impressive cycling stability up to 98% capacitance retention after 8000 cycles. The significant improvement in volumetric capacitance performance is mainly due to the increase of redox-active sites exposed by removal of surface terminal groups during alkalinizing and annealing, and the enhancement in conductivity of the film owing to the annealing induced increase of crystalline order. Moreover, the supercapacitor fabricated with ak-Ti 3 C 2 T x film-A displays an outstanding volumetric energy density of 45.2 Wh L−1. This work provides a new strategy for design and development of other MXenes-based materials with high volumetric capacitance performance for flexible and highly integrated supercapacitors. Graphical abstract Image 1 Highlights • ak-Ti 3 C 2 T x film-A by using self-assembly of Ti 3 C 2 T x followed by alkalinizing and annealing treatment is presented. • ak-Ti 3 C 2 T x film-A show a significant enhancement in volumetric capacitance performance. • The symmetric supercapacitor fabricated with ak-Ti 3 C 2 T x films-A displays an ultrahigh volumetric energy density. [ABSTRACT FROM AUTHOR]

With the continuous in-depth research and clinical exploration of related technologies in magnetic surgery, the demand for implanting NdFeB magnets has been increasing, and the surface requirements for the magnets implanted into the human body have also been continuously improved. Because of the different physiological environments of different implantation sites in the human body, the requirements for surface modification are also different. At present, the surface modification methods of NdFeB magnetic materials implanted in vivo are various, but the effect of surface modification in different parts of the human body is not yet definitive, and the lack of systematic evaluation. In this paper, the implanted environment and a variety of surface modification methods of the existing medical NdFeB magnets are summarized in detail. The problems existing in the surface modification at the current stage are summarized in order to provide ideas and directions for follow-up study. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface-modified Cu-ZnO and ZnO nanostructures have been fabricated. • XRD, FTIR, SEM, EDX, and UV–Visible spectrum carried out. • The prepared materials are used to study the electrochemical and photocatalytic properties. • By introducing Cu metal on the surface of ZnO, the electrical conductivity was increased. • The Cu modified ZnO based electrode found to be more efficient in electrochemical applications. Surface modified Cu-ZnO nanostructures with different ratios of Cu (0.0 %, 2.5 %, 5.0 %, 7.5 % and 10.0 %) have been fabricated using a simplified sol gel auto combustion method (SGAC). The utilization of aqueous methanolic solution (50:50 ratio) as the reaction medium, with zinc chloride, ZnCl2, serving as a precursor to modified Cu-ZnO nanostructures and ZnO nanostructures (NSs) in particular, was a novel aspect of this study. XRD, FTIR, SEM, EDX, and UV–Visible spectrum analyses were carried out for the analysis of products. The prepared materials were used to study the electrochemical and photocatalytic properties. By introducing Cu metal on the surface of ZnO, the electrical conductivity was increased, and this attribute was investigated using energy band gap calculations and CV analysis. The energy band gap of fabricated nanostructures found to be decreased from 3.36 to 3.20 eV. The Cu modified ZnO based electrode showed the enhanced relative electron transport and increased peak current which made it to be more efficient in electrochemical applications. Degradation study of Tartrazine azo dye (organic) was carried out to examine the photo-induced catalytic activities of prepared materials under solar radiations, UV-light and darkness. The photocatalytic activity was revealed to be optimum up to 86.12 % when exposed to solar radiations and also with increasing Cu concentration up to 10.0 % on the ZnO surface. When compared to pure ZnO, all synthesized Cu modified ZnO NSs exhibited increased peak current, enhanced relative electron transport and optimized photo-induced catalytic degradation of organic pollutant dye. It was revealed that products manufactured using the SGAC technique had higher quality and produced better results for the intended applications than those previously reported. [ABSTRACT FROM AUTHOR]

In this literature review, the current state-of-art of coatings for orthodontic archwires’ increasing antimicrobial and relevant mechanical properties, such as surface topography, friction or corrosion resistance, has been presented. There is a growing request for orthodontic appliances, therefore, most researchers focus on innovative functional coatings to cover orthodontic archwires and brackets. Orthodontic appliances are exposed to the unfavorable oral cavity environment, consisting of saliva flow, food, temperature and appliance force. As a consequence, friction or biocorrosion processes may occur. This can affect the functionality of the orthodontic elements, causing changes in their microstructure, surface topography and mechanical properties. Furthermore, the material which the orthodontic archwire is made from is of particular importance in terms of the possible corrosion resistance. This is especially important for patients who are hypersensitive to metals, for example, nickel, which causes allergic reactions. In the literature, there are some studies, carried out in vitro and in vivo, mostly examining the antibacterial, antiadherent, mechanical and roughness properties of functional coatings. They are clinically acceptable but still some properties have to be studied and be developed for better results. In this paper the influence of additives such as nanoparticles of silver and nitrogen-doped TiO2 applied on orthodontic brackets by different methods on the antimicrobial properties was analyzed. Future improvement of coating techniques as well as modification of the archwire composition can reduce the release of nickel ions and eliminate friction and bacterial adhesion problems, thus accelerating treatment time.