Biodegradable magnesium alloy stents(MAS)have great potential in the treatment of cardiovascular diseases.However,too fast degradation and the poor biocompatibility are still two key problems for the clinical utility ...Biodegradable magnesium alloy stents(MAS)have great potential in the treatment of cardiovascular diseases.However,too fast degradation and the poor biocompatibility are still two key problems for the clinical utility of MAS.In the present work,a functional coating composed of hydrophilic polymers and bioactive peptides was constructed on magnesium alloy to improve its corrosion resistance and biocompatibility in vitro and in vivo.Mg-Zn-Y-Nd(ZE21B)alloy modified with the functional coating exhibited moderate surface hydrophilicity and enhanced corrosion resistance.The favourable hemocompatibility of ZE21B alloy with the functional coating was confirmed by the in vitro blood experiments.Moreover,the modified ZE21B alloy could selectively promote the adhesion,proliferation,and migration of endothelial cells(ECs),but suppress these behaviors of smooth muscle cells(SMCs).Furthermore,the modified ZE21B alloy wires could alleviate intimal hyperplasia,enhance corrosion resistance and re-endothelialization in vivo transplantation experiment.These results collectively demonstrated that the functional coating improved the corrosion resistance and biocompatibility of ZE21B alloy.This functional coating provides new insight into the design and development of novel biodegradable stents for biomedical engineering.展开更多
Zwitterion-based materials by virtue of their special physical and chemical characteristics have attracted researchers to utilize them for fabricating functional coatings. The simultaneous presence of positive and neg...Zwitterion-based materials by virtue of their special physical and chemical characteristics have attracted researchers to utilize them for fabricating functional coatings. The simultaneous presence of positive and negative charges renders the zwitterion-based materials with electrostatically induced hydration properties, which enables a high resistance towards oily pollutants, nonspecific protein adsorption, bacterial adhesion and biofilm formation. This review starts from the working mechanism of zwitterions and covers the fabrication strategies of zwitterion-based functional coatings, namely the zwitterion-bearing binder route, the zwitterion-bearing additive route and the post-generation of coatings containing zwitterionic precursors. The applications of zwitterion-based functional coatings are discussed, including medical implants, marine antifouling and oil-resistant coatings, with focus on the relevant mechanisms of the zwitterion-containing coatings for a specific performance. Finally, some comments and perspectives on the current situation and future development of zwitterion-based functional coatings are given.展开更多
Inspired by the micro-nano structure on the surface of biological materials or living organisms,micro-nano structure has been widely investigated in the field of functional coatings.Due to its large specific surface a...Inspired by the micro-nano structure on the surface of biological materials or living organisms,micro-nano structure has been widely investigated in the field of functional coatings.Due to its large specific surface area,porosity,and dual-scale structure,it has recently attracted special attention.The typical fabrication processes of micro-nano structured coatings include sol-gel,hydrothermal synthesis,chemical vapor deposition,etc.This paper presents the main features of a recent deposition and synthesis technique,liquid plasma spraying(LPS).LPS is an important technical improvement of atmospheric plasma spraying.Compared with atmospheric plasma spraying,LPS is more suitable for preparing functional coatings with micro-nano structure.Micro-nano structured coatings are mainly classified into hierarchical-structure and binary-structure.The present study reviews the preparation technology,structural characteristics,functional properties,and potential applications of LPS coatings with a micro-nano structure.The micro-nano structured coatings obtained through tailoring the structure will present excellent performances.展开更多
This paper investigates the functionally graded coating bonded to an elastic strip with a crack under thermal- mechanical loading. Considering some new boundary conditions, it is assumed that the temperature drop acro...This paper investigates the functionally graded coating bonded to an elastic strip with a crack under thermal- mechanical loading. Considering some new boundary conditions, it is assumed that the temperature drop across the crack surface is the result of the thermal conductivity index which controls heat conduction through the crack region. By the Fourier transforms, the thermal-elastic mixed boundary value problems are reduced to a system of singular integral equations which can be approximately solved by applying the Chebyshev polynomials. The numerical computation methods for the temperature, the displacement field and the thermal stress intensity factors （TSIFs） are presented. The normal temperature distributions （NTD） with different parameters along the crack surface are analyzed by numerical examples. The influence of the crack position and the thermal-elastic non- homogeneous parameters on the TSIFs of modes I and 11 at the crack tip is presented. Results show that the variation of the thickness of the graded coating has a significant effect on the temperature jump across the crack surfaces when keeping the thickness of the substrate constant, and the thickness of functionally graded material （FGM） coating has a significant effect on the crack in the substrate. The results can be expected to be used for the purpose of gaining better understanding of the thermal-mechanical behavior of graded coatings.展开更多
Cardiovascular diseases cause huge morbidity and mortality worldwide.Recently,vascular stents have been most frequently used to treat cardiovascular diseases thanks to their effectiveness at dilating blood vessels and...Cardiovascular diseases cause huge morbidity and mortality worldwide.Recently,vascular stents have been most frequently used to treat cardiovascular diseases thanks to their effectiveness at dilating blood vessels and main-taining the circulation of blood.However,stent expansion leads to endothelium injury posing thrombogenic and in-stent restenosis(ISR).In addition,the bioinertness and an acute lack of endothelium-like function on the surface of implanted vascular stents compromise their performance.Functional coatings of vascular stents to mimic endothelium-and extracellular matrix(ECM)-like functions could prevent thrombosis,inhibit the over-growth of smooth muscle cells(SMCs),and promote the rapid restoration of native endothelium,hence effec-tively suppressing stent-related complications.Noticeably,ECM-based coatings including a multitude of bioactive molecular,such as growth factors,heparin,hyaluronic acid(HA)and so on,have been proven to play important effects on regulating ECs/SMCs behavior and improving blood compatibility of stents.Additionally,nitric oxide(NO),which is fundamental to the endothelium-mediated anti-thrombogenesity,anti-intimal hyperplasia and anti-inflammation,has been leveraged to improve vascular stent functions.Therefore,this review will highlight different strategies and biological role of ECM and NO based functional coatings on vascular stent.Lastly,some potential important factors for stents development are suggested as well.展开更多
Magnesium-based biodegradable metals as cardiovascular stents have shown a lot of excellent performance, which have been used to treat coronary artery diseases. However, the excessive degradation rate, imperfect bioco...Magnesium-based biodegradable metals as cardiovascular stents have shown a lot of excellent performance, which have been used to treat coronary artery diseases. However, the excessive degradation rate, imperfect biocompatibility and delayed re-endothelialization still lead to a considerable challenge for its application. In this work, to overcome these shortcomings, a compound of catalyzing nitric oxide(NO) generation containing copper ions(Cu^(2+)) and hyaluronic acid(HA), an important component of the extracellular matrix, were covalently immobilized on a hydrofluoric acid(HF)-pretreated ZE21B alloy via amination layer for improving its corrosion resistance and endothelialization. Specifically,the Cu^(2+) chelated firmly with a cyclen 1,4,7,10-tetraazacyclododecane-N’, N’’, N’’’, N-tetraacetic acid(DOTA) could form a stability of hybrid coating, avoiding the explosion of Cu^(2+). The chelated Cu^(2+) enabled the catalytic generation of NO and promoted the adhesion and proliferation of endothelial cells(ECs) in vascular micro-environment. In this case, the synergistic effect of NO-generation and endothelial glycocalyx molecules of HA lead to efficient ECs promotion and smooth muscle cells(SMCs) inhibition. Meanwhile, the blood compatibility also had achieved a marked improvement. Moreover, the standard electrochemical measurements indicated that the functionalized ZE21B alloy had better anti-corrosion ability. In a conclusion, the dual-functional coating displays a great potential in the field of biodegradable magnesium-based implantable cardiovascular stents.展开更多
For the first time,functionally electroless nickel plated ZrO2(NCZ)graded Ni-NCZ composite coating has been successfully co-electrodeposited from a bath with gradually increasing of stirring rate.Studies showed that c...For the first time,functionally electroless nickel plated ZrO2(NCZ)graded Ni-NCZ composite coating has been successfully co-electrodeposited from a bath with gradually increasing of stirring rate.Studies showed that co-electrodeposition in a bath with stirring rate of250r/min results in the maximum co-electrodeposited particle content and the best particle distribution.To produce NCZ graded Ni-NCZ composite coating,the stirring rate was continuously increased from0to250r/min.The electroplated coating had a continuous gradient increasing of co-electrodeposited NCZ content from substrate towards the surface.The results showed that with increasing the co-electrodeposited NCZ particles content in Ni matrix,microhardness increases from interface towards the surface of the coating.Little crystallite size of Ni matrix and higher co-electrodeposited hard particles content were recognized as the reasons of microhardness increasing.Bend test revealed that the functionally graded composite coating shows more excellent adhesion to the substrate compared with the ordinary distributed Ni-NCZ on the same substrate.This result is attributed to lower mechanical mismatch between coating and substrate in the functionally graded composite coating with respect to the uniformly distributed one.The results of wear resistance measurements reveal that wear resistance of functionally graded Ni-NCZ is higher than that of ordinary distributed composite coating.展开更多
The functionally graded thermal barrier coatings （FG-TBCs） with 80%ZrO2-13%CeO2-7%Y2O3 （C-YSZ）/NiCoCrAlY were prepared using a recently developed supersonic plasma spraying（S-PS） with dual powder feed ports syst...The functionally graded thermal barrier coatings （FG-TBCs） with 80%ZrO2-13%CeO2-7%Y2O3 （C-YSZ）/NiCoCrAlY were prepared using a recently developed supersonic plasma spraying（S-PS） with dual powder feed ports system. The thermal shock experiment of FG-TBCs specimens was carried out by means of the automatic thermal cycle device, in which the samples were heated to 1200℃ by oxygen-acetylene flame jet then water-quenched to ambient temperature. The temperature—time curves of specimens and photographs can be watched on-line and recorded by a computer during the test. The results show that the totally 1mm-thick FG-TBCs have excellent thermal shock resistance due to the fact that the coatings have no any peeling-off after 200 thermal cycles. The microstructures and morphologies of FG-TBCs were characterized and analyzed by SEM.展开更多
Functionalization of polymer foams by surface coating is of great interest for advanced flow-interactive materials working with well-controlled 3D open channels.However,realizing heavy functional coating via a fast an...Functionalization of polymer foams by surface coating is of great interest for advanced flow-interactive materials working with well-controlled 3D open channels.However,realizing heavy functional coating via a fast and recyclable way remains a big challenge.Here,inspired by the battery electrodes,we propose a scalable mechanic-assisted heavy coating strategy based on the design of sticky jammed fluid(SJF)to conquer the above challenge.Similar to the electrode slurry,the SJF is dominated by a high concentration of active material(≥20 wt%of active carbon,for instance)uniformly dispersed in a protein binder solution.Due to the sticky and solidrich nature of the SJF,one can realize a high coating efficiency of 60 wt%gain per coating.The critical factors controlling the coating processing and quality are further identified and discussed.Furthermore,the functionalized foam is demonstrated as a high-performance shape-customizable toxic gas remover,which can absorb formaldehyde very efficiently at different circumstances,including static adsorption,flow-based filtration,and source interception.Finally,the foam skeleton and the active materials are easily recycled by a facile solvent treatment.This study may inspire new scalable way for fast,heavy,and customizable functionalization of polymeric foams.展开更多
We present a bidirectional reflection distribution function （BRDF） model for thermal coating surfaces based on a three-component reflection assumption, in which the specular reflection is given according to the micr...We present a bidirectional reflection distribution function （BRDF） model for thermal coating surfaces based on a three-component reflection assumption, in which the specular reflection is given according to the microfacet theory and Snell＇s law, the multiple reflection is considered Nth cosine distributed, and the volume scattering is uniformly distributed in reflection angles according to the experimental results. This model describes the reflection characteristics of thermal coating surfaces more completely and reasonably. Simulation and measurement results of two thermal coating samples SR107 and S781 are given to validate that this three-component model significantly improves the modeling accuracy for thermal coating surfaces compared with the existing BRDF models.展开更多
Silver coatings on the exterior surface of monolithic activated carbon（MAC） with different morphology were prepared by directly immersing MAC into [Ag（NH3）2]NO3 solution. Acid and base treatments were employed to ...Silver coatings on the exterior surface of monolithic activated carbon（MAC） with different morphology were prepared by directly immersing MAC into [Ag（NH3）2]NO3 solution. Acid and base treatments were employed to modify the surface oxygenic groups of MAC, respectively. The MACs＇ Brunauer-EmmettTeller（BET） surface area, surface groups, and silver coating morphology were characterized by N2 adsorption, elemental analysis（EA）, X-ray photoelectron spectroscopy（XPS）, and scanning electron microscopy（SEM）, respectively. The coating morphology was found to be closely related to the surface area and surface functional groups of MAC. For a raw MAC which contained a variety of oxygenic groups, HNO3 treatment enhanced the relative amount of highly oxidized groups such as carboxyl and carbonates, which disfavored the deposition of silver particles. By contrast, Na OH treatment significantly improved the amount of carbonyl groups, which in turn improved the deposition amount of silver. Importantly, lamella silver was produced on raw MAC while Na OH treatment resulted in granular particles because of the capping effect of carbonyl groups. At appropriate [Ag（NH3）2]NO3 concentrations, silver nanoparticles smaller than 100 nm were homogeneously dispersed on Na OH-treated MAC. The successful tuning of the size and morphology of silver coatings on MAC is promising for novel applications in air purification and for antibacterial or aesthetic purposes.展开更多
The mechanical integrity and reliability of coated devices are strongly affected by the residual stresses in thin films and coatings. However, due to the metallurgical complexity of materials, it is rather difficult t...The mechanical integrity and reliability of coated devices are strongly affected by the residual stresses in thin films and coatings. However, due to the metallurgical complexity of materials, it is rather difficult to obtain a closed-form solution of residual stresses within multilayered coatings （e.g. functionally graded coatings, FGCs）. In this paper,an analytical model is developed to predict the distribution of residual stresses within multilayered coatings. The advantage of this model is that the solution of residual stresses is independent of the number of layers. Specific results are obtained by calculating elastic thermal stresses in ZrO2/NiCoCrAIY FGCs, which consist of different material layers. Furthermore, the residual stress distribution near the edges and the stress-induced failure modes of coating are also analyzed. The topics discussed provide some insights into the development of a methodology for designing fail-safe coating systems.展开更多
The material design is used to direct the magnetron cosputtering process. At first, according to the particularity of functionally gradient coat (FGC) the thermal elastic stress analysis for FGC was carried out based ...The material design is used to direct the magnetron cosputtering process. At first, according to the particularity of functionally gradient coat (FGC) the thermal elastic stress analysis for FGC was carried out based on the plane stress hypothesis. It is obtained that the peak value of plane thermal stress within FGC is only determined by the physical properties of materials of FGC and substrate, the composition distribution coefficient only influences the distribution and trend of plane thermal stress. And the plane thermal stress criterion for design of FGC was presented. Then the plane thermal stress of diamond like carbon/titanium alloy FGC was calculated.展开更多
To tackle energy crisis and achieve sustainable development, aqueous rechargeable zinc ion batteries have gained widespread attention in large-scale energy storage for their low cost, high safety, high theoretical cap...To tackle energy crisis and achieve sustainable development, aqueous rechargeable zinc ion batteries have gained widespread attention in large-scale energy storage for their low cost, high safety, high theoretical capacity, and environmental compatibility in recent years. However, zinc anode in aqueous zinc ion batteries is still facing several challenges such as dendrite growth and side reactions(e.g., hydrogen evolution), which cause poor reversibility and the failure of batteries. To address these issues, interfacial modification of Zn anodes has received great attention by tuning the interaction between the anode and the electrolyte. Herein, we present recent advances in the interfacial modification of zinc anode in this review. Besides, the challenges of reported approaches of interfacial modification are also discussed.Finally, we provide an outlook for the exploration of novel zinc anode for aqueous zinc ion batteries.We hope that this review will be helpful in designing and fabricating dendrite-free and hydrogenevolution-free Zn anodes and promoting the practical application of aqueous rechargeable zinc ion batteries.展开更多
In order to improve the adhesion of the middle frequency magnetic sputtered zirconium coating on a polyurethane film,an anode layer source was used to pretreat the polyurethane film with nitrogen and oxygen ions.SEMs ...In order to improve the adhesion of the middle frequency magnetic sputtered zirconium coating on a polyurethane film,an anode layer source was used to pretreat the polyurethane film with nitrogen and oxygen ions.SEMs and AFM roughness profiles of treated samples and the contrast groups were obtained.Besides,XPS survey spectrums and high resolution spectrums were also investigated.The adhesion test revealed that ion bombardment could improve the adhesion to the polyurethane coating substrate.A better etching result of oxygen ions versus nitrogen predicts a higher bonding strength of zirconium coating on polyurethane and,indeed,the highest bonding strengths are for oxygen ion bombardment upto 13.3 MPa.As demonstrated in X-ray photoelectron spectroscopy,the oxygen ion also helps to introduce more active groups,and,therefore,it achieves a high value of adhesion strength.展开更多
In the presented work, the possibility of direct synthesis of LDH(layered double hydroxide) on the AZ91 surface in the presence of a chelating agent(diethylenetriaminepentaacetic acid-DTPA) is reported. Conversion lay...In the presented work, the possibility of direct synthesis of LDH(layered double hydroxide) on the AZ91 surface in the presence of a chelating agent(diethylenetriaminepentaacetic acid-DTPA) is reported. Conversion layer of LDH nanocontainers were formed under ambient pressure conditions without carbonate addition in the electrolyte. The obtained LDH was characterized using experimental(SEM,XRD, TGA, XPS, Raman, etc.) and computational methods(thermodynamic calculation, modeling of possible LDH crystal structures). A comparison of three possible LDHs(LDH-OH,-NO_(3) and-CO_(3)) was performed. Based on the experimental results and crystal simulation approach, it was confirmed, that the mixed LDH-OH/CO_(3) is grown on the surface in the presence of DTPA pentasodium salt.展开更多
In this article,graphene oxide(GO)and benzotriazole-loaded mesoporous silica nanoparticles(BTA/MSNs)are combined on micro scale through the in situ polymerization of polydopamine(PDA),preparing a selfhealing bi-functi...In this article,graphene oxide(GO)and benzotriazole-loaded mesoporous silica nanoparticles(BTA/MSNs)are combined on micro scale through the in situ polymerization of polydopamine(PDA),preparing a selfhealing bi-functional GO(fGO)used as nano-fillers for anti-corrosion enhancement of waterborne epoxy(WEP)coatings.Scanning electronic microscopy(SEM)images show that the BTA/MSNs are uniformly distributed on the surface of high aspect ratio GO nanosheets to endow GO nanocontainer characteristics.UV-vis profiles demonstrate that fGO has p H-controlled release function.Modulus at lowest frequency is generally used for comparing the corrosion resistance of organic coatings.Modulus at lowest frequency(1.42×10^(5)Ωcm^(2))after 30 days immersion in 3.5 wt.%Na Cl solution revealed 2 orders of magnitude higher that of blank WEP(1.17×10^(7)Ωcm^(2)).With artificial cracks on its coatings,fGO/WEP had no obvious rust compared with blank WEP after 240 h of immersion.We anticipate that self-healing and physical barrier bi-functional nanocontainers improve the traditional anticorrosion coating efficiency with better,longer-lasting performance for shipping,oil drilling or bridge maintenance.展开更多
This investigation evaluates, by the dislocation method, the dynamic stress intensity factors of cracked orthotropic half-plane and functionally graded material coating of a coating- substrate material due to the acti...This investigation evaluates, by the dislocation method, the dynamic stress intensity factors of cracked orthotropic half-plane and functionally graded material coating of a coating- substrate material due to the action of anti-plane traction on the crack surfaces. First, by using the complex Fourier transform, the dislocation problem can be solved and the stress fields are obtained with Cauchy singularity at the location of dislocation. The dislocation solution is utilized to derive integral equations for multiple interacting cracks in the orthotropic half-plane with functionally graded orthotropic coating. Several examples are solved and dynamic stress intensity factors are obtained.展开更多
Demand for biliary stents has expanded with the increasing incidence of biliary disease.The implantation of plastic or self-expandable metal stents can be an effective treatment for biliary strictures.However,these st...Demand for biliary stents has expanded with the increasing incidence of biliary disease.The implantation of plastic or self-expandable metal stents can be an effective treatment for biliary strictures.However,these stents are nondegradable and prone to restenosis.Surgical removal or replacement of the nondegradable stents is necessary in cases of disease resolution or restenosis.To overcome these shortcomings,improvements were made to the materials and surfaces used for the stents.First,this paper reviews the advantages and limitations of nondegradable stents.Second,emphasis is placed on biodegradable polymer and biodegradable metal stents,along with functional coatings.This also encompasses tissue engineering&3D-printed stents were highlighted.Finally,the future perspectives of biliary stents,including pro-epithelialization coatings,multifunctional coated stents,biodegradable shape memory stents,and 4D bioprinting,were discussed.展开更多
The need to combine various metals in light-weight constructions requires the development of coatings that prevent galvanic corrosion.Layered double hydroxides(LDHs)can be an example of such coatings,which were previo...The need to combine various metals in light-weight constructions requires the development of coatings that prevent galvanic corrosion.Layered double hydroxides(LDHs)can be an example of such coatings,which were previously successfully obtained in situ on individual materials.In addition,the possibility of LDH growth(including LDH growth in the presence of chelating agents)on the surface of plasma electrolytic oxidation(PEO)-coated metals was previously shown.This PEO+LDH combination could improve both corrosion and mechanical characteristics of the system.The possibility of LDHs formation in situ on the surface of PEO-coated friction stir welded(FSW)magnesium-aluminum materials(AZ31/AA5754 system was selected as a model one)was demonstrated in the presence of 1,3-diamino-2-hydroxypropane-N,N,N',N'-tetraacetic acid(DHPTA)as a chelating agent,which was selected based on analysis of respective metal-ligand compounds stability.LDHs growth was achieved under ambient pressure without addition of carbonates in the electrolyte.The effectiveness of the resulting coating is shown both for corrosion resistance and hardness.展开更多
基金project was the National Natural Science Foundation of China(Grant No.52101291)China Postdoctoral Science Foundation(Grant No.2020TQ0273)+1 种基金the National Key Research and Development Program of China(Grant No.2018YFC1106703)the Key Projects of the Joint Fund of the National Natural Science Foundation of China(Grant No.U1804251)。
文摘Biodegradable magnesium alloy stents(MAS)have great potential in the treatment of cardiovascular diseases.However,too fast degradation and the poor biocompatibility are still two key problems for the clinical utility of MAS.In the present work,a functional coating composed of hydrophilic polymers and bioactive peptides was constructed on magnesium alloy to improve its corrosion resistance and biocompatibility in vitro and in vivo.Mg-Zn-Y-Nd(ZE21B)alloy modified with the functional coating exhibited moderate surface hydrophilicity and enhanced corrosion resistance.The favourable hemocompatibility of ZE21B alloy with the functional coating was confirmed by the in vitro blood experiments.Moreover,the modified ZE21B alloy could selectively promote the adhesion,proliferation,and migration of endothelial cells(ECs),but suppress these behaviors of smooth muscle cells(SMCs).Furthermore,the modified ZE21B alloy wires could alleviate intimal hyperplasia,enhance corrosion resistance and re-endothelialization in vivo transplantation experiment.These results collectively demonstrated that the functional coating improved the corrosion resistance and biocompatibility of ZE21B alloy.This functional coating provides new insight into the design and development of novel biodegradable stents for biomedical engineering.
基金Sponsored by the National Key Research and Development Program of China(Grant No.2020YFE0100300)the National Natural Science Foundation of China(Grant No.51973036)。
文摘Zwitterion-based materials by virtue of their special physical and chemical characteristics have attracted researchers to utilize them for fabricating functional coatings. The simultaneous presence of positive and negative charges renders the zwitterion-based materials with electrostatically induced hydration properties, which enables a high resistance towards oily pollutants, nonspecific protein adsorption, bacterial adhesion and biofilm formation. This review starts from the working mechanism of zwitterions and covers the fabrication strategies of zwitterion-based functional coatings, namely the zwitterion-bearing binder route, the zwitterion-bearing additive route and the post-generation of coatings containing zwitterionic precursors. The applications of zwitterion-based functional coatings are discussed, including medical implants, marine antifouling and oil-resistant coatings, with focus on the relevant mechanisms of the zwitterion-containing coatings for a specific performance. Finally, some comments and perspectives on the current situation and future development of zwitterion-based functional coatings are given.
基金supported by the National Key R&D Program of China(Grant No.2017YFE0115900)the National Natural Science Foundation of China(Grant No.51872254)the Yangzhou City-Yangzhou University Cooperation Foundation(Grant No.YZU201801).
文摘Inspired by the micro-nano structure on the surface of biological materials or living organisms,micro-nano structure has been widely investigated in the field of functional coatings.Due to its large specific surface area,porosity,and dual-scale structure,it has recently attracted special attention.The typical fabrication processes of micro-nano structured coatings include sol-gel,hydrothermal synthesis,chemical vapor deposition,etc.This paper presents the main features of a recent deposition and synthesis technique,liquid plasma spraying(LPS).LPS is an important technical improvement of atmospheric plasma spraying.Compared with atmospheric plasma spraying,LPS is more suitable for preparing functional coatings with micro-nano structure.Micro-nano structured coatings are mainly classified into hierarchical-structure and binary-structure.The present study reviews the preparation technology,structural characteristics,functional properties,and potential applications of LPS coatings with a micro-nano structure.The micro-nano structured coatings obtained through tailoring the structure will present excellent performances.
基金The National Natural Science Foundation of China(No.10962008,51061015)Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20116401110002)
文摘This paper investigates the functionally graded coating bonded to an elastic strip with a crack under thermal- mechanical loading. Considering some new boundary conditions, it is assumed that the temperature drop across the crack surface is the result of the thermal conductivity index which controls heat conduction through the crack region. By the Fourier transforms, the thermal-elastic mixed boundary value problems are reduced to a system of singular integral equations which can be approximately solved by applying the Chebyshev polynomials. The numerical computation methods for the temperature, the displacement field and the thermal stress intensity factors （TSIFs） are presented. The normal temperature distributions （NTD） with different parameters along the crack surface are analyzed by numerical examples. The influence of the crack position and the thermal-elastic non- homogeneous parameters on the TSIFs of modes I and 11 at the crack tip is presented. Results show that the variation of the thickness of the graded coating has a significant effect on the temperature jump across the crack surfaces when keeping the thickness of the substrate constant, and the thickness of functionally graded material （FGM） coating has a significant effect on the crack in the substrate. The results can be expected to be used for the purpose of gaining better understanding of the thermal-mechanical behavior of graded coatings.
基金supported by grants from the National Natural Science Foundation of China(82172106,32050410286)and Tian-jin"Project+Team"Key Training Foundation(XC202035)Science and Technology Commission of Shanghai Municipality(19441902600,20S31900900,20DZ2254900)。
文摘Cardiovascular diseases cause huge morbidity and mortality worldwide.Recently,vascular stents have been most frequently used to treat cardiovascular diseases thanks to their effectiveness at dilating blood vessels and main-taining the circulation of blood.However,stent expansion leads to endothelium injury posing thrombogenic and in-stent restenosis(ISR).In addition,the bioinertness and an acute lack of endothelium-like function on the surface of implanted vascular stents compromise their performance.Functional coatings of vascular stents to mimic endothelium-and extracellular matrix(ECM)-like functions could prevent thrombosis,inhibit the over-growth of smooth muscle cells(SMCs),and promote the rapid restoration of native endothelium,hence effec-tively suppressing stent-related complications.Noticeably,ECM-based coatings including a multitude of bioactive molecular,such as growth factors,heparin,hyaluronic acid(HA)and so on,have been proven to play important effects on regulating ECs/SMCs behavior and improving blood compatibility of stents.Additionally,nitric oxide(NO),which is fundamental to the endothelium-mediated anti-thrombogenesity,anti-intimal hyperplasia and anti-inflammation,has been leveraged to improve vascular stent functions.Therefore,this review will highlight different strategies and biological role of ECM and NO based functional coatings on vascular stent.Lastly,some potential important factors for stents development are suggested as well.
基金supported by the National Key R&D Program of China (grant number 2021YFC2400700)National Natural Science Foundation of China (Nos.51871004 and U1804251)。
文摘Magnesium-based biodegradable metals as cardiovascular stents have shown a lot of excellent performance, which have been used to treat coronary artery diseases. However, the excessive degradation rate, imperfect biocompatibility and delayed re-endothelialization still lead to a considerable challenge for its application. In this work, to overcome these shortcomings, a compound of catalyzing nitric oxide(NO) generation containing copper ions(Cu^(2+)) and hyaluronic acid(HA), an important component of the extracellular matrix, were covalently immobilized on a hydrofluoric acid(HF)-pretreated ZE21B alloy via amination layer for improving its corrosion resistance and endothelialization. Specifically,the Cu^(2+) chelated firmly with a cyclen 1,4,7,10-tetraazacyclododecane-N’, N’’, N’’’, N-tetraacetic acid(DOTA) could form a stability of hybrid coating, avoiding the explosion of Cu^(2+). The chelated Cu^(2+) enabled the catalytic generation of NO and promoted the adhesion and proliferation of endothelial cells(ECs) in vascular micro-environment. In this case, the synergistic effect of NO-generation and endothelial glycocalyx molecules of HA lead to efficient ECs promotion and smooth muscle cells(SMCs) inhibition. Meanwhile, the blood compatibility also had achieved a marked improvement. Moreover, the standard electrochemical measurements indicated that the functionalized ZE21B alloy had better anti-corrosion ability. In a conclusion, the dual-functional coating displays a great potential in the field of biodegradable magnesium-based implantable cardiovascular stents.
文摘For the first time,functionally electroless nickel plated ZrO2(NCZ)graded Ni-NCZ composite coating has been successfully co-electrodeposited from a bath with gradually increasing of stirring rate.Studies showed that co-electrodeposition in a bath with stirring rate of250r/min results in the maximum co-electrodeposited particle content and the best particle distribution.To produce NCZ graded Ni-NCZ composite coating,the stirring rate was continuously increased from0to250r/min.The electroplated coating had a continuous gradient increasing of co-electrodeposited NCZ content from substrate towards the surface.The results showed that with increasing the co-electrodeposited NCZ particles content in Ni matrix,microhardness increases from interface towards the surface of the coating.Little crystallite size of Ni matrix and higher co-electrodeposited hard particles content were recognized as the reasons of microhardness increasing.Bend test revealed that the functionally graded composite coating shows more excellent adhesion to the substrate compared with the ordinary distributed Ni-NCZ on the same substrate.This result is attributed to lower mechanical mismatch between coating and substrate in the functionally graded composite coating with respect to the uniformly distributed one.The results of wear resistance measurements reveal that wear resistance of functionally graded Ni-NCZ is higher than that of ordinary distributed composite coating.
文摘The functionally graded thermal barrier coatings （FG-TBCs） with 80%ZrO2-13%CeO2-7%Y2O3 （C-YSZ）/NiCoCrAlY were prepared using a recently developed supersonic plasma spraying（S-PS） with dual powder feed ports system. The thermal shock experiment of FG-TBCs specimens was carried out by means of the automatic thermal cycle device, in which the samples were heated to 1200℃ by oxygen-acetylene flame jet then water-quenched to ambient temperature. The temperature—time curves of specimens and photographs can be watched on-line and recorded by a computer during the test. The results show that the totally 1mm-thick FG-TBCs have excellent thermal shock resistance due to the fact that the coatings have no any peeling-off after 200 thermal cycles. The microstructures and morphologies of FG-TBCs were characterized and analyzed by SEM.
基金sponsored by the Double First-Class Construction Funds of Sichuan University and National Natural Science Foundation of China(NNSFC)financial support from the National Natural Science Foundation of China(NNSFC grants 51873126,51422305,and 51721091).
文摘Functionalization of polymer foams by surface coating is of great interest for advanced flow-interactive materials working with well-controlled 3D open channels.However,realizing heavy functional coating via a fast and recyclable way remains a big challenge.Here,inspired by the battery electrodes,we propose a scalable mechanic-assisted heavy coating strategy based on the design of sticky jammed fluid(SJF)to conquer the above challenge.Similar to the electrode slurry,the SJF is dominated by a high concentration of active material(≥20 wt%of active carbon,for instance)uniformly dispersed in a protein binder solution.Due to the sticky and solidrich nature of the SJF,one can realize a high coating efficiency of 60 wt%gain per coating.The critical factors controlling the coating processing and quality are further identified and discussed.Furthermore,the functionalized foam is demonstrated as a high-performance shape-customizable toxic gas remover,which can absorb formaldehyde very efficiently at different circumstances,including static adsorption,flow-based filtration,and source interception.Finally,the foam skeleton and the active materials are easily recycled by a facile solvent treatment.This study may inspire new scalable way for fast,heavy,and customizable functionalization of polymeric foams.
文摘We present a bidirectional reflection distribution function （BRDF） model for thermal coating surfaces based on a three-component reflection assumption, in which the specular reflection is given according to the microfacet theory and Snell＇s law, the multiple reflection is considered Nth cosine distributed, and the volume scattering is uniformly distributed in reflection angles according to the experimental results. This model describes the reflection characteristics of thermal coating surfaces more completely and reasonably. Simulation and measurement results of two thermal coating samples SR107 and S781 are given to validate that this three-component model significantly improves the modeling accuracy for thermal coating surfaces compared with the existing BRDF models.
基金Funded by the Interdisciplinary Program of Shanghai Jiao Tong University(YG2016MS24)
文摘Silver coatings on the exterior surface of monolithic activated carbon（MAC） with different morphology were prepared by directly immersing MAC into [Ag（NH3）2]NO3 solution. Acid and base treatments were employed to modify the surface oxygenic groups of MAC, respectively. The MACs＇ Brunauer-EmmettTeller（BET） surface area, surface groups, and silver coating morphology were characterized by N2 adsorption, elemental analysis（EA）, X-ray photoelectron spectroscopy（XPS）, and scanning electron microscopy（SEM）, respectively. The coating morphology was found to be closely related to the surface area and surface functional groups of MAC. For a raw MAC which contained a variety of oxygenic groups, HNO3 treatment enhanced the relative amount of highly oxidized groups such as carboxyl and carbonates, which disfavored the deposition of silver particles. By contrast, Na OH treatment significantly improved the amount of carbonyl groups, which in turn improved the deposition amount of silver. Importantly, lamella silver was produced on raw MAC while Na OH treatment resulted in granular particles because of the capping effect of carbonyl groups. At appropriate [Ag（NH3）2]NO3 concentrations, silver nanoparticles smaller than 100 nm were homogeneously dispersed on Na OH-treated MAC. The successful tuning of the size and morphology of silver coatings on MAC is promising for novel applications in air purification and for antibacterial or aesthetic purposes.
基金the priority support provided by the National Natural Science Foundation of China(No.50235030)the National Development Scheme of Kev Fundamental Research(National“973”Proiect)of China(No.G1999065009)“863”Project(No.2003AA331130).
文摘The mechanical integrity and reliability of coated devices are strongly affected by the residual stresses in thin films and coatings. However, due to the metallurgical complexity of materials, it is rather difficult to obtain a closed-form solution of residual stresses within multilayered coatings （e.g. functionally graded coatings, FGCs）. In this paper,an analytical model is developed to predict the distribution of residual stresses within multilayered coatings. The advantage of this model is that the solution of residual stresses is independent of the number of layers. Specific results are obtained by calculating elastic thermal stresses in ZrO2/NiCoCrAIY FGCs, which consist of different material layers. Furthermore, the residual stress distribution near the edges and the stress-induced failure modes of coating are also analyzed. The topics discussed provide some insights into the development of a methodology for designing fail-safe coating systems.
文摘The material design is used to direct the magnetron cosputtering process. At first, according to the particularity of functionally gradient coat (FGC) the thermal elastic stress analysis for FGC was carried out based on the plane stress hypothesis. It is obtained that the peak value of plane thermal stress within FGC is only determined by the physical properties of materials of FGC and substrate, the composition distribution coefficient only influences the distribution and trend of plane thermal stress. And the plane thermal stress criterion for design of FGC was presented. Then the plane thermal stress of diamond like carbon/titanium alloy FGC was calculated.
基金financial support from the National Natural Science Foundation of China (52272261 and 52104300)。
文摘To tackle energy crisis and achieve sustainable development, aqueous rechargeable zinc ion batteries have gained widespread attention in large-scale energy storage for their low cost, high safety, high theoretical capacity, and environmental compatibility in recent years. However, zinc anode in aqueous zinc ion batteries is still facing several challenges such as dendrite growth and side reactions(e.g., hydrogen evolution), which cause poor reversibility and the failure of batteries. To address these issues, interfacial modification of Zn anodes has received great attention by tuning the interaction between the anode and the electrolyte. Herein, we present recent advances in the interfacial modification of zinc anode in this review. Besides, the challenges of reported approaches of interfacial modification are also discussed.Finally, we provide an outlook for the exploration of novel zinc anode for aqueous zinc ion batteries.We hope that this review will be helpful in designing and fabricating dendrite-free and hydrogenevolution-free Zn anodes and promoting the practical application of aqueous rechargeable zinc ion batteries.
文摘In order to improve the adhesion of the middle frequency magnetic sputtered zirconium coating on a polyurethane film,an anode layer source was used to pretreat the polyurethane film with nitrogen and oxygen ions.SEMs and AFM roughness profiles of treated samples and the contrast groups were obtained.Besides,XPS survey spectrums and high resolution spectrums were also investigated.The adhesion test revealed that ion bombardment could improve the adhesion to the polyurethane coating substrate.A better etching result of oxygen ions versus nitrogen predicts a higher bonding strength of zirconium coating on polyurethane and,indeed,the highest bonding strengths are for oxygen ion bombardment upto 13.3 MPa.As demonstrated in X-ray photoelectron spectroscopy,the oxygen ion also helps to introduce more active groups,and,therefore,it achieves a high value of adhesion strength.
基金financial support of the I2B fund(Helmholtz Association)in frame of MUFfin project as well as ACTICOAT project in frame of Erafinancial support within the project CICECO-Aveiro Institute of Materials(UIDB/50011/2020&UIDP/50011/2020)financed by national funds through the FCT/MCTES and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement。
文摘In the presented work, the possibility of direct synthesis of LDH(layered double hydroxide) on the AZ91 surface in the presence of a chelating agent(diethylenetriaminepentaacetic acid-DTPA) is reported. Conversion layer of LDH nanocontainers were formed under ambient pressure conditions without carbonate addition in the electrolyte. The obtained LDH was characterized using experimental(SEM,XRD, TGA, XPS, Raman, etc.) and computational methods(thermodynamic calculation, modeling of possible LDH crystal structures). A comparison of three possible LDHs(LDH-OH,-NO_(3) and-CO_(3)) was performed. Based on the experimental results and crystal simulation approach, it was confirmed, that the mixed LDH-OH/CO_(3) is grown on the surface in the presence of DTPA pentasodium salt.
基金supported by the National Natural Science Foundation of China(Grant No.51908031)the China Scholarship Council for a graduate fellowship(201906150013)+2 种基金the support from Guangdong Special Support Program(Grant No.2017TX04N371)ERC Enercapsule project(647969)Royal Society project IECR2202163。
文摘In this article,graphene oxide(GO)and benzotriazole-loaded mesoporous silica nanoparticles(BTA/MSNs)are combined on micro scale through the in situ polymerization of polydopamine(PDA),preparing a selfhealing bi-functional GO(fGO)used as nano-fillers for anti-corrosion enhancement of waterborne epoxy(WEP)coatings.Scanning electronic microscopy(SEM)images show that the BTA/MSNs are uniformly distributed on the surface of high aspect ratio GO nanosheets to endow GO nanocontainer characteristics.UV-vis profiles demonstrate that fGO has p H-controlled release function.Modulus at lowest frequency is generally used for comparing the corrosion resistance of organic coatings.Modulus at lowest frequency(1.42×10^(5)Ωcm^(2))after 30 days immersion in 3.5 wt.%Na Cl solution revealed 2 orders of magnitude higher that of blank WEP(1.17×10^(7)Ωcm^(2)).With artificial cracks on its coatings,fGO/WEP had no obvious rust compared with blank WEP after 240 h of immersion.We anticipate that self-healing and physical barrier bi-functional nanocontainers improve the traditional anticorrosion coating efficiency with better,longer-lasting performance for shipping,oil drilling or bridge maintenance.
文摘This investigation evaluates, by the dislocation method, the dynamic stress intensity factors of cracked orthotropic half-plane and functionally graded material coating of a coating- substrate material due to the action of anti-plane traction on the crack surfaces. First, by using the complex Fourier transform, the dislocation problem can be solved and the stress fields are obtained with Cauchy singularity at the location of dislocation. The dislocation solution is utilized to derive integral equations for multiple interacting cracks in the orthotropic half-plane with functionally graded orthotropic coating. Several examples are solved and dynamic stress intensity factors are obtained.
基金supported by grants from the Fundamental Research Funds for the Central Universities(No.2024CDJCGJ-016)National Natural Science Foundation of China(No.82270535)+1 种基金the Science and Technology Innovation Project of Jinfeng Laboratory,Chongqing,China(jfkyjf202203001)China Postdoctoral Science Foundation(2023MD734198).
文摘Demand for biliary stents has expanded with the increasing incidence of biliary disease.The implantation of plastic or self-expandable metal stents can be an effective treatment for biliary strictures.However,these stents are nondegradable and prone to restenosis.Surgical removal or replacement of the nondegradable stents is necessary in cases of disease resolution or restenosis.To overcome these shortcomings,improvements were made to the materials and surfaces used for the stents.First,this paper reviews the advantages and limitations of nondegradable stents.Second,emphasis is placed on biodegradable polymer and biodegradable metal stents,along with functional coatings.This also encompasses tissue engineering&3D-printed stents were highlighted.Finally,the future perspectives of biliary stents,including pro-epithelialization coatings,multifunctional coated stents,biodegradable shape memory stents,and 4D bioprinting,were discussed.
基金the financial support of the FUNCOAT project(Development and design of novel multifunctional PEO COATings,H2020-RISE-2019-2024,No.823942)the I2B funding in frame MUFfin projectACTICOAT project in frame of Era。
文摘The need to combine various metals in light-weight constructions requires the development of coatings that prevent galvanic corrosion.Layered double hydroxides(LDHs)can be an example of such coatings,which were previously successfully obtained in situ on individual materials.In addition,the possibility of LDH growth(including LDH growth in the presence of chelating agents)on the surface of plasma electrolytic oxidation(PEO)-coated metals was previously shown.This PEO+LDH combination could improve both corrosion and mechanical characteristics of the system.The possibility of LDHs formation in situ on the surface of PEO-coated friction stir welded(FSW)magnesium-aluminum materials(AZ31/AA5754 system was selected as a model one)was demonstrated in the presence of 1,3-diamino-2-hydroxypropane-N,N,N',N'-tetraacetic acid(DHPTA)as a chelating agent,which was selected based on analysis of respective metal-ligand compounds stability.LDHs growth was achieved under ambient pressure without addition of carbonates in the electrolyte.The effectiveness of the resulting coating is shown both for corrosion resistance and hardness.
