Additive manufacturing provides achievability for the fabrication of bimetallic and multi-material structures;however,the material compatibility and bondability directly affect the parts’formability and final quality...Additive manufacturing provides achievability for the fabrication of bimetallic and multi-material structures;however,the material compatibility and bondability directly affect the parts’formability and final quality.It is essential to understand the underlying printability of different material combinations based on an adapted process.Here,the printability disparities of two common and attractive material combinations(nickel-and iron-based alloys)are evaluated at the macro and micro levels via laser directed energy deposition(DED).The deposition processes were captured using in situ high-speed imaging,and the dissimilarities in melt pool features and track morphology were quantitatively investigated within specific process windows.Moreover,the microstructure diversity of the tracks and blocks processed with varied material pairs was comparatively elaborated and,complemented with the informative multi-physics modeling,the presented non-uniformity in mechanical properties(microhardness)among the heterogeneous material pairs was rationalized.The differences in melt flow induced by the unlike thermophysical properties of the material pairs and the resulting element intermixing and localized re-alloying during solidification dominate the presented dissimilarity in printability among the material combinations.This work provides an in-depth understanding of the phenomenological differences in the deposition of dissimilar materials and aims to guide more reliable DED forming of bimetallic parts.展开更多
Direct ink writing(DIW)holds enormous potential in fabricating multiscale and multi-functional architectures by virtue of its wide range of printable materials,simple operation,and ease of rapid prototyping.Although i...Direct ink writing(DIW)holds enormous potential in fabricating multiscale and multi-functional architectures by virtue of its wide range of printable materials,simple operation,and ease of rapid prototyping.Although it is well known that ink rheology and processing parameters have a direct impact on the resolution and shape of the printed objects,the underlying mechanisms of these key factors on the printability and quality of DIW technique remain poorly understood.To tackle this issue,we systematically analyzed the printability and quality through extrusion mechanism modeling and experimental validating.Hybrid non-Newtonian fluid inks were first prepared,and their rheological properties were measured.Then,finite element analysis of the whole DIW process was conducted to reveal the flow dynamics of these inks.The obtained optimal process parameters(ink rheology,applied pressure,printing speed,etc)were also validated by experiments where high-resolution(<100μm)patterns were fabricated rapidly(>70 mm s^(-1)).Finally,as a process research demonstration,we printed a series of microstructures and circuit systems with hybrid inks and silver inks,showing the suitability of the printable process parameters.This study provides a strong quantitative illustration of the use of DIW for the high-speed preparation of high-resolution,high-precision samples.展开更多
Three-dimensional(3D)extrusion-based bioprinting is widely used in tissue engineering and regenerative medicine to create cell-incorporated constructs or scaffolds based on the extrusion technique.One critical issue i...Three-dimensional(3D)extrusion-based bioprinting is widely used in tissue engineering and regenerative medicine to create cell-incorporated constructs or scaffolds based on the extrusion technique.One critical issue in 3D extrusion-based bioprinting is printability or the capability to form and maintain reproducible 3D scaffolds from bioink(a mixture of biomaterials and cells).Research shows that printability can be affected by many factors or parameters,including those associated with the bioink,printing process,and scaffold design,but these are far from certain.This review highlights recent developments in the printability assessment of extrusion-based bioprinting with a focus on the definition of printability,printability measurements and characterization,and printability-affecting factors.Key issues and challenges related to printability are also identified and discussed,along with approaches or strategies for improving printability in extrusion-based bioprinting.展开更多
Recently, 3D bioprinting is developed as an emerging approach, increasingly applied to materials for healthcare;while, the precise placement of cells and materials, and the shape fidelity of forming constructs is of g...Recently, 3D bioprinting is developed as an emerging approach, increasingly applied to materials for healthcare;while, the precise placement of cells and materials, and the shape fidelity of forming constructs is of great importance for successful application of 3D bioprinting. Research efforts have been made to develop new bioinks as "raw materials" with better biocompatibility and biofunctionality, but the printability of bioinks is largely ignored and still needs to be carefully examined to enable robotic bioprinting. This article aims to introduce a recent published review (Appl. Phys. Rev. 2018, 5, 041304) on the evaluation of bioink printability by Huang's research group from University of Florida. Huang et al. comprehensively reviewed the bioink printability based on the physical point of view during inkjet printing, laser printing, and microextrusion, and a series of self-consistent time scales and dimensi on less quantities were utilized to physically understand and evaluate bioink printability. This article would be helpful to know the trends on physical understanding of bioink printability.展开更多
Rheological properties of microemulsions(MEs) and their printability in three dimensional printing(3DP) systems were investigated.A series of MEs with different contents of oil phase were prepared using sonication met...Rheological properties of microemulsions(MEs) and their printability in three dimensional printing(3DP) systems were investigated.A series of MEs with different contents of oil phase were prepared using sonication method with ibuprofen as model drug and soybean lecithin as emulfier.Stationary and transient rheological properties of MEs were investigated by ARES-SRF using concentric cylinders measuring systems.3DP systems with piezoelectric drop-on-demand print heads were employed to test the printability of the MEs.Results demonstrate that the apparent viscosity and dynamic linear viscoelastic regions of the MEs are the most important parameters for continuous and stable printing of MEs by 3DP.The incorporation of drug in the MEs has little influence on the MEs' stationary rheological behaviors and dynamic viscoelasticity,but the concentration of oil phase has a strong influence on them.The rheological property of binder liquids has a close relationship with their printability in 3DP system.展开更多
Using an in situ lunar regolith as a construction material in combination with 3D printing not only reduces the weight of materials carried from the Earth but also improves the automation of lunar infrastructure const...Using an in situ lunar regolith as a construction material in combination with 3D printing not only reduces the weight of materials carried from the Earth but also improves the automation of lunar infrastructure construction.This study aims to improve the printability of a geopolymer based on a BH-1 lunar regolith simulant,including the extrudability,open time,and buildability,by controlling the temperature and adding admixtures.Rheological parameters were used to represent printability with different water-to-binder ratios,printing temperatures,and contents of additives.The mechanical properties of the hardening geopolymer with different filling paths and loading directions were tested.The results show that heating the printed filaments with a water-to-binder ratio of 0.32 at 80°C can adjust the printability without adding any additive,which can reduce the construction cost of lunar infrastructure.The printability of the BH-1 geopolymer can also be improved by adding 0.3%Attagel-50 and 0.5%polypropylene fiber by mass at a temperature of 20℃to cope with the changeable environmental conditions on the Moon.After curing under a simulated lunar environment,the 72-h flexural and compressive strengths of the geopolymer specimens reach 4.1 and 48.1 MPa,respectively,which are promising considering that the acceleration of gravity on the Moon is 1/6 of that on the Earth.展开更多
The extrusion-based bioprinting(EBBP)applications in the medical field tremendously increase due to its ver-satility in fabricating intricate geometry components with reasonable accuracy and precision.The bioink and i...The extrusion-based bioprinting(EBBP)applications in the medical field tremendously increase due to its ver-satility in fabricating intricate geometry components with reasonable accuracy and precision.The bioink and its properties for an EBBP process are crucial in manufacturing parts with significant biocompatibility and functionality.The EBBP demands optimized parameters for obtaining good printability and cell viability.A better understanding of the various process parameters is essential for the researcher to optimize the mechanical and biological properties of the printed constructs.The biological,mechanical,and rheological parameters all together need to be evaluated to enhance the printability of tissue.This article concisely delineates the effect of the rheological and physiochemical parameters on the biological and mechanical properties of the printed tissues.The printing parameters and nozzle geometry,which considerably influence the printability,and shape fidelity of the bioprinted scaffolds are exemplified in detail.Additionally,the challenges and future aspects of enhancing printability are discussed succinctly.展开更多
Lightweight aluminum(Al)alloys have been widely used in frontier fields like aerospace and automotive industries,which attracts great interest in additive manufacturing(AM)to process high-value Al parts.As a mainstrea...Lightweight aluminum(Al)alloys have been widely used in frontier fields like aerospace and automotive industries,which attracts great interest in additive manufacturing(AM)to process high-value Al parts.As a mainstream AM technique,laser-directed energy deposition(LDED)shows good scalability to meet the requirements for large-format component manufacturing and repair.However,LDED Al alloys are highly challenging due to their inherent poor printability(e.g.low laser absorption,high oxidation sensitivity and cracking tendency).To further promote the development of LDED high-performance Al alloys,this review offers a deep understanding of the challenges and strategies to improve printability in LDED Al alloys.The porosity,cracking,distortion,inclusions,element evaporation and resultant inferior mechanical properties(worse than laser powder bed fusion)are the key challenges in LDED Al alloys.Processing parameter optimizations,in-situ alloy design,reinforcing particle addition and field assistance are the efficient approaches to improving the printability and performance of LDED Al alloys.The underlying correlations between processes,alloy innovation,characteristic microstructures,and achievable performances in LDED Al alloys are discussed.The benchmark mechanical properties and primary strengthening mechanism of LDED Al alloys are summarized.This review aims to provide a critical and in-depth evaluation of current progress in LDED Al alloys.Future opportunities and perspectives in LDED high-performance Al alloys are also outlined.展开更多
Metal additive manufacturing(AM)has been extensively studied in recent decades.Despite the significant progress achieved in manufacturing complex shapes and structures,challenges such as severe cracking when using exi...Metal additive manufacturing(AM)has been extensively studied in recent decades.Despite the significant progress achieved in manufacturing complex shapes and structures,challenges such as severe cracking when using existing alloys for laser powder bed fusion(L-PBF)AM have persisted.These challenges arise because commercial alloys are primarily designed for conventional casting or forging processes,overlooking the fast cooling rates,steep temperature gradients and multiple thermal cycles of L-PBF.To address this,there is an urgent need to develop novel alloys specifically tailored for L-PBF technologies.This review provides a comprehensive summary of the strategies employed in alloy design for L-PBF.It aims to guide future research on designing novel alloys dedicated to L-PBF instead of adapting existing alloys.The review begins by discussing the features of the L-PBF processes,focusing on rapid solidification and intrinsic heat treatment.Next,the printability of the four main existing alloys(Fe-,Ni-,Al-and Ti-based alloys)is critically assessed,with a comparison of their conventional weldability.It was found that the weldability criteria are not always applicable in estimating printability.Furthermore,the review presents recent advances in alloy development and associated strategies,categorizing them into crack mitigation-oriented,microstructure manipulation-oriented and machine learning-assisted approaches.Lastly,an outlook and suggestions are given to highlight the issues that need to be addressed in future work.展开更多
This paper discusses the use of atmospheric pressure dielectric barrier discharge(DBD)plasma treatment to enhance the surface qualities of viscose fabrics.The study explores the effects of different plasma gases,disch...This paper discusses the use of atmospheric pressure dielectric barrier discharge(DBD)plasma treatment to enhance the surface qualities of viscose fabrics.The study explores the effects of different plasma gases,discharge voltages,and exposure times on the treated fabrics.The findings emphasize the importance of optimizing the plasma's peak voltage to achieve the desired surface treatment outcomes.The document also presents data on colour strength,wettability,colour fastness,and tensile strength of the treated fabrics,as well as scanning electron microscopy(SEM)analysis of surface morphology and chemical analysis using fouriertransition infrared spectroscopy(FTIR)and energy dispersive X-ray(EDX).The results show that treatment at a peak voltage of 11.83 k V is more efficient,except for the tensile strength which is enhanced at a peak voltage of 8.92 k V.The oxygen plasma treatment significantly improves the colour strength,which exhibits an increase from 11 to 18.The intensified colour was attributed to the significant influence of electrostatic interactions between the charged hydroxyl groups of the oxygen plasma treated viscose textiles and the dye molecules,which enhance the printability.The oxygen DBD plasma exhibits a higher ability to enhance the properties of textiles when compared to air and argon plasmas.This study presents a sustainable,economical,secure,and ecologically friendly approach to explore new fabrics for specific uses.展开更多
Three-dimensional(3D)printing and bioprinting have come into view for a plannable and standardizable generation of implantable tissue-engineered constructs that can substitute native tissues and organs.These tissue-en...Three-dimensional(3D)printing and bioprinting have come into view for a plannable and standardizable generation of implantable tissue-engineered constructs that can substitute native tissues and organs.These tissue-engineered structures are intended to integrate with the patient’s body.Vascular tissue engineering(TE)is relevant in TE because it supports the sustained oxygenization and nutrition of all tissue-engineered constructs.Bioinks have a specific role,representingthenecessarymedium for printability and vascular cell growth.This review aims to understand the requirements for the design of vascular bioinks.First,an in-depth analysis of vascular cell interaction with their native environment must be gained.A physiological bioink suitable for a tissue-engineered vascular graft(TEVG)must not only ensure good printability but also induce cells to behave like in a native vascular vessel,including self-regenerative and growth functions.This review describes the general structure of vascular walls with wall-specific cell and extracellular matrix(ECM)components and biomechanical properties and functions.Furthermore,the physiological role of vascular ECM components for their interaction with vascular cells and the mode of interaction is introduced.Diverse currently available or imaginable bioinks are described from physiological matrix proteins to nonphysiologically occurring but natural chemical compounds useful for vascular bioprinting.The physiological performance of these bioinks is evaluated with regard to biomechanical properties postprinting,with a view to current animal studies of 3D printed vascular structures.Finally,the main challenges for further bioink development,suitable bioink components to create a self-assembly bioink concept,and future bioprinting strategies are outlined.These concepts are discussed in terms of their suitability to be part of a TEVG with a high potential for later clinical use.展开更多
The development of portable X-ray detectors is necessary for diagnosing fractures in unconscious patients in emergency situations.However,this is quite challenging because of the heavy weight of the scintillator and s...The development of portable X-ray detectors is necessary for diagnosing fractures in unconscious patients in emergency situations.However,this is quite challenging because of the heavy weight of the scintillator and silicon photodetectors.The weight and thickness of X-ray detectors can be reduced by replacing the silicon layer with an organic photodetectors.This study presents a novel bithienopyrroledione-based polymer donor that exhibits excellent photodetection properties even in a thick photoactive layer(~700 nm),owing to the symmetric backbone and highly soluble molecular structure of bithienopyrroledione.The ability of bithienopyrroledione-based polymer donor to strongly suppress the dark current density(Jd~10−10 A cm^(−2))at a negative bias(−2.0 V)while maintaining high responsivity(R=0.29 A W−1)even at a thickness of 700 nm results in a maximum shot-noise-limited specific detectivity of D_(sh)^(*)=2.18×10^(13)Jones in the organic photodetectors.Printed organic photodetectors are developed by slot-die coating for use in X-ray detectors,which exhibit D_(sh)^(*)=2.73×10^(12)Jones with clear rising(0.26 s)and falling(0.29 s)response times upon X-ray irradiation.Detection reliability is also proven by linear response of the X-ray detector,and the X-ray detection limit is 3 mA.展开更多
The low-cost and easy large-scale fabrication advantages of printable mesoscopic perovskite solar cells(p-MPSCs)are overshadowed by their limited photovoltaic conversion efficiency(PCE).Here,we introduce the hydrazide...The low-cost and easy large-scale fabrication advantages of printable mesoscopic perovskite solar cells(p-MPSCs)are overshadowed by their limited photovoltaic conversion efficiency(PCE).Here,we introduce the hydrazide derivative of 4-Hydroxybenzoylhydrazine(4-HBH)to improve the PCE of p-MPSCs by inducing enhanced defect passivation.Both carbonyl and hydrazine groups in hydrazide groups present strong interaction with perovskite.The hydroxyl group,as an electron donor group,increases the electron cloud density of the hydrazide group in 4-HBH under the conjugation of the benzene ring,and thus enhances its interaction with perovskite.Additionally,the hydroxy group itself interacts with perovskite and passivates defects synergistically.The hydrazine agents can also reduce I2and suppress the loss of iodine in perovskite films,which inhibits the formation of iodine-related defects.Consequently,p-MPSCs with 4-HBH achieve a high PCE of 19.21%,and present well improved stability.展开更多
In order to mimic the natural heterogeneity of native tissue and provide a better microenvironment for cell culturing,multi-material bioprinting has become a common solution to construct tissue models in vitro.With th...In order to mimic the natural heterogeneity of native tissue and provide a better microenvironment for cell culturing,multi-material bioprinting has become a common solution to construct tissue models in vitro.With the embedded printing method,complex 3D structure can be printed using soft biomaterials with reasonable shape fidelity.However,the current sequential multi-material embedded printing method faces a major challenge,which is the inevitable trade-off between the printed structural integrity and printing precision.Here,we propose a simultaneous multi-material embedded printing method.With this method,we can easily print firmly attached and high-precision multilayer structures.With multiple individually controlled nozzles,different biomaterials can be precisely deposited into a single crevasse,minimizing uncontrolled squeezing and guarantees no contamination of embedding medium within the structure.We analyse the dynamics of the extruded bioink in the embedding medium both analytically and experimentally,and quantitatively evaluate the effects of printing parameters including printing speed and rheology of embedding medium,on the 3D morphology of the printed filament.We demonstrate the printing of double-layer thin-walled structures,each layer less than 200μm,as well as intestine and liver models with 5%gelatin methacryloyl that are crosslinked and extracted from the embedding medium without significant impairment or delamination.The peeling test further proves that the proposed method offers better structural integrity than conventional sequential printing methods.The proposed simultaneous multi-material embedded printing method can serve as a powerful tool to support the complex heterogeneous structure fabrication and open unique prospects for personalized medicine.展开更多
The droplet formation dynamics of a Newtonian liquid in a drop-on-demand (DOD) inkjet process is numerically investigated by using a volume-of-fluid (VOF) method. We focus on the nozzle geometry, wettability of the in...The droplet formation dynamics of a Newtonian liquid in a drop-on-demand (DOD) inkjet process is numerically investigated by using a volume-of-fluid (VOF) method. We focus on the nozzle geometry, wettability of the interior surface, and the fluid properties to achieve the stable droplet formation with higher velocity. It is found that a nozzle with contracting angle of 45° generates the most stable and fastest single droplet, which is beneficial for the enhanced printing quality and high-throughput printing rate. For this nozzle with the optimal geometry, we systematically change the wettability of the interior surface, i.e., different contact angles. As the contact angle increases, pinch-off time increases and the droplet speed reduces. Finally, fluids with different properties are investigated to identify the printability range.展开更多
Acellular dermal matrix(ADM)as a biomaterial is currently believed to be promising tissue repair improvement.With the development of tissue engineering,ADM is increasingly used as biological scaffolds.We explored the ...Acellular dermal matrix(ADM)as a biomaterial is currently believed to be promising tissue repair improvement.With the development of tissue engineering,ADM is increasingly used as biological scaffolds.We explored the feasibility and performance of ADM biological scaffolds that fabricated by 3D printing.This paper presented our study on the printability of 3D printed ADM scaffolds,with a focus on identifying the influence of printing parameters/conditions on printability.To characterize the printability,we examined the fiber morphology,pore size,strand diameter,and mechanical property of the printed scaffolds.Our results revealed that the printability could be affected by a number of factors and among them,the most considerable one was related to the nozzle diameter and the composition of ADM.We then evaluated the biocompatibility in terms of cytotoxicity,cell proliferation and vivisection.In vitro evaluation of the ADM scaffolds was carried out and the experimental results indicated that cells were viable and proliferative during the period of study.In vivo results also indicated that the defect area was well repaired without any noticeable infection,hematoma and other conditions.In conclusion,ADM could be reconstructed with 3D printing technology and ADM biological scaffold has potential applications for tissue engineering.展开更多
The discovery of laser-induced graphene(LIG) from polymers in 2014 has aroused much attention in recent years.A broad range of applications,including batteries,catalysis,sterilization,and separation,have been explored...The discovery of laser-induced graphene(LIG) from polymers in 2014 has aroused much attention in recent years.A broad range of applications,including batteries,catalysis,sterilization,and separation,have been explored.The advantages of LIG technology over conventional graphene synthesis methods are conspicuous,which include designable patterning,environmental friendliness,tunable compositions,and controllable morphologies.In addition,LIG possesses high porosity,great flexibility,and mechanical robustness,and excellent electric and thermal conductivity.The patternable and printable manufacturing process and the advantageous properties of LIG illuminate a new pathway for developing miniaturized graphene devices.Its use in sensing applications has grown swiftly from a single detection component to an integrated smart detection system.In this minireview,we start with the introduction of synthetic efforts related to the fabrication of LIG sensors.Then,we highlight the achievement of LIG sensors for the detection of a diversity of stimuli with a focus on the design principle and working mechanism.Future development of the techniques toward in situ and smart detection of multiple stimuli in widespread applications will be discussed.展开更多
Perovskite-based photovoltaic materials have been attracting attention for their strikingly improved performance at converting sunlight into electricity.The beneficial and unique optoelectronic characteristics of pero...Perovskite-based photovoltaic materials have been attracting attention for their strikingly improved performance at converting sunlight into electricity.The beneficial and unique optoelectronic characteristics of perovskite structures enable researchers to achieve an incredibly remarkable power conversion efficiency.Flexible hybrid perovskite photovoltaics promise emerging applications in a myriad of optoelectronic and wearable/portable device applications owing to their inherent intriguing physicochemical and photophysical properties which enabled researchers to take forward advanced research in this growing field.Flexible perovskite photovoltaics have attracted significant attention owing to their fascinating material properties with combined merits of high efficiency,light-weight,flexibility,semitransparency,compatibility towards roll-to-roll printing,and large-area mass-scale production.Flexible perovskite-based solar cells comprise of 4 key components that include a flexible substrate,semi-transparent bottom contact electrode,perovskite(light absorber layer)and charge transport(electron/hole)layers and top(usually metal)electrode.Among these components,interfacial layers and contact electrodes play a pivotal role in influencing the overall photovoltaic performance.In this comprehensive review article,we focus on the current developments and latest progress achieved in perovskite photovoltaics concerning the charge selective transport layers/electrodes toward the fabrication of highly stable,efficient flexible devices.As a concluding remark,we briefly summarize the highlights of the review article and make recommendations for future outlook and investigation with perspectives on the perovskite-based optoelectronic functional devices that can be potentially utilized in smart wearable and portable devices.展开更多
Formation of copper wiring on a polyimide film by laser irradiation to a stable copper-complex film consisting of glyoxylic acid copper complex and methylamine copper complex in air has been investigated. A stable met...Formation of copper wiring on a polyimide film by laser irradiation to a stable copper-complex film consisting of glyoxylic acid copper complex and methylamine copper complex in air has been investigated. A stable metallic copper on the polyimide film was precipitated even in air. Since this copper was generated only in the laser-irradiated parts, direct patterning of copper wiring was possible. It was also found that copper was precipitated by electroless copper plating on the laser-deposited copper wiring and it was possible to thicken the copper wiring by this precipitation. The resistivity of the copper wiring was almost the same as that of the bulk of metallic copper. The developed method—combining laser irradiation to a copper-complex-coated film and electroless copper plating—enables the high-speed deposition of fine copper wiring on a polyimide film in air by a printing process, indicating an inexpensive and useful process for fabricating copper wiring without high vacuum facility and heat-treatment under inert gas.展开更多
基金supported by the National Natural Science Foundation of China(51975112,52375412)Fundamental Research Funds for Central Universities(N2203011)。
文摘Additive manufacturing provides achievability for the fabrication of bimetallic and multi-material structures;however,the material compatibility and bondability directly affect the parts’formability and final quality.It is essential to understand the underlying printability of different material combinations based on an adapted process.Here,the printability disparities of two common and attractive material combinations(nickel-and iron-based alloys)are evaluated at the macro and micro levels via laser directed energy deposition(DED).The deposition processes were captured using in situ high-speed imaging,and the dissimilarities in melt pool features and track morphology were quantitatively investigated within specific process windows.Moreover,the microstructure diversity of the tracks and blocks processed with varied material pairs was comparatively elaborated and,complemented with the informative multi-physics modeling,the presented non-uniformity in mechanical properties(microhardness)among the heterogeneous material pairs was rationalized.The differences in melt flow induced by the unlike thermophysical properties of the material pairs and the resulting element intermixing and localized re-alloying during solidification dominate the presented dissimilarity in printability among the material combinations.This work provides an in-depth understanding of the phenomenological differences in the deposition of dissimilar materials and aims to guide more reliable DED forming of bimetallic parts.
基金supported by National Natural Science Foundation of China(Nos.52188102,U2013213,51820105008)the Technology Innovation Project of Hubei Province of China under Grant No.2019AEA171+1 种基金The project of introducing innovative leading talents in Songshan Lake High-tech Zone,Dongguan City,Guangdong Province(No.2019342101RSFJ-G)the support from Flexible Electronics Research Center of HUST for providing experiment facility。
文摘Direct ink writing(DIW)holds enormous potential in fabricating multiscale and multi-functional architectures by virtue of its wide range of printable materials,simple operation,and ease of rapid prototyping.Although it is well known that ink rheology and processing parameters have a direct impact on the resolution and shape of the printed objects,the underlying mechanisms of these key factors on the printability and quality of DIW technique remain poorly understood.To tackle this issue,we systematically analyzed the printability and quality through extrusion mechanism modeling and experimental validating.Hybrid non-Newtonian fluid inks were first prepared,and their rheological properties were measured.Then,finite element analysis of the whole DIW process was conducted to reveal the flow dynamics of these inks.The obtained optimal process parameters(ink rheology,applied pressure,printing speed,etc)were also validated by experiments where high-resolution(<100μm)patterns were fabricated rapidly(>70 mm s^(-1)).Finally,as a process research demonstration,we printed a series of microstructures and circuit systems with hybrid inks and silver inks,showing the suitability of the printable process parameters.This study provides a strong quantitative illustration of the use of DIW for the high-speed preparation of high-resolution,high-precision samples.
基金The authors acknowledge financial support from the Natural Sciences and Engineering Research Council of Canada(NSERC,Grant No.:RGPIN-2014-05648).
文摘Three-dimensional(3D)extrusion-based bioprinting is widely used in tissue engineering and regenerative medicine to create cell-incorporated constructs or scaffolds based on the extrusion technique.One critical issue in 3D extrusion-based bioprinting is printability or the capability to form and maintain reproducible 3D scaffolds from bioink(a mixture of biomaterials and cells).Research shows that printability can be affected by many factors or parameters,including those associated with the bioink,printing process,and scaffold design,but these are far from certain.This review highlights recent developments in the printability assessment of extrusion-based bioprinting with a focus on the definition of printability,printability measurements and characterization,and printability-affecting factors.Key issues and challenges related to printability are also identified and discussed,along with approaches or strategies for improving printability in extrusion-based bioprinting.
文摘Recently, 3D bioprinting is developed as an emerging approach, increasingly applied to materials for healthcare;while, the precise placement of cells and materials, and the shape fidelity of forming constructs is of great importance for successful application of 3D bioprinting. Research efforts have been made to develop new bioinks as "raw materials" with better biocompatibility and biofunctionality, but the printability of bioinks is largely ignored and still needs to be carefully examined to enable robotic bioprinting. This article aims to introduce a recent published review (Appl. Phys. Rev. 2018, 5, 041304) on the evaluation of bioink printability by Huang's research group from University of Florida. Huang et al. comprehensively reviewed the bioink printability based on the physical point of view during inkjet printing, laser printing, and microextrusion, and a series of self-consistent time scales and dimensi on less quantities were utilized to physically understand and evaluate bioink printability. This article would be helpful to know the trends on physical understanding of bioink printability.
基金Project(B07024) supported by Biomedical Textile Materials "111 Project" from Ministry of Education of ChinaProject(50773009) supported by the National Natural Science Foundation of ChinaProject(Grant IRT0526) supported by Program for Changjiang Scholars and Innovative Research Team in University
文摘Rheological properties of microemulsions(MEs) and their printability in three dimensional printing(3DP) systems were investigated.A series of MEs with different contents of oil phase were prepared using sonication method with ibuprofen as model drug and soybean lecithin as emulfier.Stationary and transient rheological properties of MEs were investigated by ARES-SRF using concentric cylinders measuring systems.3DP systems with piezoelectric drop-on-demand print heads were employed to test the printability of the MEs.Results demonstrate that the apparent viscosity and dynamic linear viscoelastic regions of the MEs are the most important parameters for continuous and stable printing of MEs by 3DP.The incorporation of drug in the MEs has little influence on the MEs' stationary rheological behaviors and dynamic viscoelasticity,but the concentration of oil phase has a strong influence on them.The rheological property of binder liquids has a close relationship with their printability in 3DP system.
基金supported by the National Natural Science Foundation of China(Grant Nos.42241128,51978029)Key Laboratory of Road and Traffic Engineering of the Ministry of Education,Tongji University(No.K202206)+1 种基金China Postdoctoral Science Foundation(No.2023M730174)Young Elite Scientist Sponsorship Program by Beijing Association for Science and Technology(No.BYESS2023418).
文摘Using an in situ lunar regolith as a construction material in combination with 3D printing not only reduces the weight of materials carried from the Earth but also improves the automation of lunar infrastructure construction.This study aims to improve the printability of a geopolymer based on a BH-1 lunar regolith simulant,including the extrudability,open time,and buildability,by controlling the temperature and adding admixtures.Rheological parameters were used to represent printability with different water-to-binder ratios,printing temperatures,and contents of additives.The mechanical properties of the hardening geopolymer with different filling paths and loading directions were tested.The results show that heating the printed filaments with a water-to-binder ratio of 0.32 at 80°C can adjust the printability without adding any additive,which can reduce the construction cost of lunar infrastructure.The printability of the BH-1 geopolymer can also be improved by adding 0.3%Attagel-50 and 0.5%polypropylene fiber by mass at a temperature of 20℃to cope with the changeable environmental conditions on the Moon.After curing under a simulated lunar environment,the 72-h flexural and compressive strengths of the geopolymer specimens reach 4.1 and 48.1 MPa,respectively,which are promising considering that the acceleration of gravity on the Moon is 1/6 of that on the Earth.
文摘The extrusion-based bioprinting(EBBP)applications in the medical field tremendously increase due to its ver-satility in fabricating intricate geometry components with reasonable accuracy and precision.The bioink and its properties for an EBBP process are crucial in manufacturing parts with significant biocompatibility and functionality.The EBBP demands optimized parameters for obtaining good printability and cell viability.A better understanding of the various process parameters is essential for the researcher to optimize the mechanical and biological properties of the printed constructs.The biological,mechanical,and rheological parameters all together need to be evaluated to enhance the printability of tissue.This article concisely delineates the effect of the rheological and physiochemical parameters on the biological and mechanical properties of the printed tissues.The printing parameters and nozzle geometry,which considerably influence the printability,and shape fidelity of the bioprinted scaffolds are exemplified in detail.Additionally,the challenges and future aspects of enhancing printability are discussed succinctly.
基金supported by the 2022 MTC Young Individual Research Grants(Grant No.M22K3c0097)the Singapore Research,Innovation and Enterprise(RIE)2025 PlanSingapore Aerospace Programme Cycle 16(Grant No.M2215a0073)。
文摘Lightweight aluminum(Al)alloys have been widely used in frontier fields like aerospace and automotive industries,which attracts great interest in additive manufacturing(AM)to process high-value Al parts.As a mainstream AM technique,laser-directed energy deposition(LDED)shows good scalability to meet the requirements for large-format component manufacturing and repair.However,LDED Al alloys are highly challenging due to their inherent poor printability(e.g.low laser absorption,high oxidation sensitivity and cracking tendency).To further promote the development of LDED high-performance Al alloys,this review offers a deep understanding of the challenges and strategies to improve printability in LDED Al alloys.The porosity,cracking,distortion,inclusions,element evaporation and resultant inferior mechanical properties(worse than laser powder bed fusion)are the key challenges in LDED Al alloys.Processing parameter optimizations,in-situ alloy design,reinforcing particle addition and field assistance are the efficient approaches to improving the printability and performance of LDED Al alloys.The underlying correlations between processes,alloy innovation,characteristic microstructures,and achievable performances in LDED Al alloys are discussed.The benchmark mechanical properties and primary strengthening mechanism of LDED Al alloys are summarized.This review aims to provide a critical and in-depth evaluation of current progress in LDED Al alloys.Future opportunities and perspectives in LDED high-performance Al alloys are also outlined.
基金financially supported by the National Key Research and Development Program of China(2022YFB4600302)National Natural Science Foundation of China(52090041)+1 种基金National Natural Science Foundation of China(52104368)National Major Science and Technology Projects of China(J2019-VII-0010-0150)。
文摘Metal additive manufacturing(AM)has been extensively studied in recent decades.Despite the significant progress achieved in manufacturing complex shapes and structures,challenges such as severe cracking when using existing alloys for laser powder bed fusion(L-PBF)AM have persisted.These challenges arise because commercial alloys are primarily designed for conventional casting or forging processes,overlooking the fast cooling rates,steep temperature gradients and multiple thermal cycles of L-PBF.To address this,there is an urgent need to develop novel alloys specifically tailored for L-PBF technologies.This review provides a comprehensive summary of the strategies employed in alloy design for L-PBF.It aims to guide future research on designing novel alloys dedicated to L-PBF instead of adapting existing alloys.The review begins by discussing the features of the L-PBF processes,focusing on rapid solidification and intrinsic heat treatment.Next,the printability of the four main existing alloys(Fe-,Ni-,Al-and Ti-based alloys)is critically assessed,with a comparison of their conventional weldability.It was found that the weldability criteria are not always applicable in estimating printability.Furthermore,the review presents recent advances in alloy development and associated strategies,categorizing them into crack mitigation-oriented,microstructure manipulation-oriented and machine learning-assisted approaches.Lastly,an outlook and suggestions are given to highlight the issues that need to be addressed in future work.
文摘This paper discusses the use of atmospheric pressure dielectric barrier discharge(DBD)plasma treatment to enhance the surface qualities of viscose fabrics.The study explores the effects of different plasma gases,discharge voltages,and exposure times on the treated fabrics.The findings emphasize the importance of optimizing the plasma's peak voltage to achieve the desired surface treatment outcomes.The document also presents data on colour strength,wettability,colour fastness,and tensile strength of the treated fabrics,as well as scanning electron microscopy(SEM)analysis of surface morphology and chemical analysis using fouriertransition infrared spectroscopy(FTIR)and energy dispersive X-ray(EDX).The results show that treatment at a peak voltage of 11.83 k V is more efficient,except for the tensile strength which is enhanced at a peak voltage of 8.92 k V.The oxygen plasma treatment significantly improves the colour strength,which exhibits an increase from 11 to 18.The intensified colour was attributed to the significant influence of electrostatic interactions between the charged hydroxyl groups of the oxygen plasma treated viscose textiles and the dye molecules,which enhance the printability.The oxygen DBD plasma exhibits a higher ability to enhance the properties of textiles when compared to air and argon plasmas.This study presents a sustainable,economical,secure,and ecologically friendly approach to explore new fabrics for specific uses.
文摘Three-dimensional(3D)printing and bioprinting have come into view for a plannable and standardizable generation of implantable tissue-engineered constructs that can substitute native tissues and organs.These tissue-engineered structures are intended to integrate with the patient’s body.Vascular tissue engineering(TE)is relevant in TE because it supports the sustained oxygenization and nutrition of all tissue-engineered constructs.Bioinks have a specific role,representingthenecessarymedium for printability and vascular cell growth.This review aims to understand the requirements for the design of vascular bioinks.First,an in-depth analysis of vascular cell interaction with their native environment must be gained.A physiological bioink suitable for a tissue-engineered vascular graft(TEVG)must not only ensure good printability but also induce cells to behave like in a native vascular vessel,including self-regenerative and growth functions.This review describes the general structure of vascular walls with wall-specific cell and extracellular matrix(ECM)components and biomechanical properties and functions.Furthermore,the physiological role of vascular ECM components for their interaction with vascular cells and the mode of interaction is introduced.Diverse currently available or imaginable bioinks are described from physiological matrix proteins to nonphysiologically occurring but natural chemical compounds useful for vascular bioprinting.The physiological performance of these bioinks is evaluated with regard to biomechanical properties postprinting,with a view to current animal studies of 3D printed vascular structures.Finally,the main challenges for further bioink development,suitable bioink components to create a self-assembly bioink concept,and future bioprinting strategies are outlined.These concepts are discussed in terms of their suitability to be part of a TEVG with a high potential for later clinical use.
基金granted by the Korea Research Institute of Chemical Technology(KRICT)of the Republic of Korea(No.2422-10)the National Research Foundation(NRF)(NRF-2021R1C1C2007445 and RS-2023-00280495)of Republic of Korea.
文摘The development of portable X-ray detectors is necessary for diagnosing fractures in unconscious patients in emergency situations.However,this is quite challenging because of the heavy weight of the scintillator and silicon photodetectors.The weight and thickness of X-ray detectors can be reduced by replacing the silicon layer with an organic photodetectors.This study presents a novel bithienopyrroledione-based polymer donor that exhibits excellent photodetection properties even in a thick photoactive layer(~700 nm),owing to the symmetric backbone and highly soluble molecular structure of bithienopyrroledione.The ability of bithienopyrroledione-based polymer donor to strongly suppress the dark current density(Jd~10−10 A cm^(−2))at a negative bias(−2.0 V)while maintaining high responsivity(R=0.29 A W−1)even at a thickness of 700 nm results in a maximum shot-noise-limited specific detectivity of D_(sh)^(*)=2.18×10^(13)Jones in the organic photodetectors.Printed organic photodetectors are developed by slot-die coating for use in X-ray detectors,which exhibit D_(sh)^(*)=2.73×10^(12)Jones with clear rising(0.26 s)and falling(0.29 s)response times upon X-ray irradiation.Detection reliability is also proven by linear response of the X-ray detector,and the X-ray detection limit is 3 mA.
基金financial support from the National Natural Science Foundation of China(Grant Nos.52172198,51902117,91733301)。
文摘The low-cost and easy large-scale fabrication advantages of printable mesoscopic perovskite solar cells(p-MPSCs)are overshadowed by their limited photovoltaic conversion efficiency(PCE).Here,we introduce the hydrazide derivative of 4-Hydroxybenzoylhydrazine(4-HBH)to improve the PCE of p-MPSCs by inducing enhanced defect passivation.Both carbonyl and hydrazine groups in hydrazide groups present strong interaction with perovskite.The hydroxyl group,as an electron donor group,increases the electron cloud density of the hydrazide group in 4-HBH under the conjugation of the benzene ring,and thus enhances its interaction with perovskite.Additionally,the hydroxy group itself interacts with perovskite and passivates defects synergistically.The hydrazine agents can also reduce I2and suppress the loss of iodine in perovskite films,which inhibits the formation of iodine-related defects.Consequently,p-MPSCs with 4-HBH achieve a high PCE of 19.21%,and present well improved stability.
基金the support by National Key Research and Development Program of China(2018YFA0703000)National Natural Science Foundation of China(Grant No.52105310)+1 种基金Natural Science Foundation of Zhejiang Province(Grant No.LDQ23E050001)the Starry Night Science Fund of Zhejiang University Shanghai Institute for Advanced Study(Grant No.SN-ZJU-SIAS-004)。
文摘In order to mimic the natural heterogeneity of native tissue and provide a better microenvironment for cell culturing,multi-material bioprinting has become a common solution to construct tissue models in vitro.With the embedded printing method,complex 3D structure can be printed using soft biomaterials with reasonable shape fidelity.However,the current sequential multi-material embedded printing method faces a major challenge,which is the inevitable trade-off between the printed structural integrity and printing precision.Here,we propose a simultaneous multi-material embedded printing method.With this method,we can easily print firmly attached and high-precision multilayer structures.With multiple individually controlled nozzles,different biomaterials can be precisely deposited into a single crevasse,minimizing uncontrolled squeezing and guarantees no contamination of embedding medium within the structure.We analyse the dynamics of the extruded bioink in the embedding medium both analytically and experimentally,and quantitatively evaluate the effects of printing parameters including printing speed and rheology of embedding medium,on the 3D morphology of the printed filament.We demonstrate the printing of double-layer thin-walled structures,each layer less than 200μm,as well as intestine and liver models with 5%gelatin methacryloyl that are crosslinked and extracted from the embedding medium without significant impairment or delamination.The peeling test further proves that the proposed method offers better structural integrity than conventional sequential printing methods.The proposed simultaneous multi-material embedded printing method can serve as a powerful tool to support the complex heterogeneous structure fabrication and open unique prospects for personalized medicine.
基金Project supported by the National Natural Science Foundation of China(No.11802004)
文摘The droplet formation dynamics of a Newtonian liquid in a drop-on-demand (DOD) inkjet process is numerically investigated by using a volume-of-fluid (VOF) method. We focus on the nozzle geometry, wettability of the interior surface, and the fluid properties to achieve the stable droplet formation with higher velocity. It is found that a nozzle with contracting angle of 45° generates the most stable and fastest single droplet, which is beneficial for the enhanced printing quality and high-throughput printing rate. For this nozzle with the optimal geometry, we systematically change the wettability of the interior surface, i.e., different contact angles. As the contact angle increases, pinch-off time increases and the droplet speed reduces. Finally, fluids with different properties are investigated to identify the printability range.
基金This research was funded by National Natural Science Foundation of China,Grant Nos.51775324 and 81970455.
文摘Acellular dermal matrix(ADM)as a biomaterial is currently believed to be promising tissue repair improvement.With the development of tissue engineering,ADM is increasingly used as biological scaffolds.We explored the feasibility and performance of ADM biological scaffolds that fabricated by 3D printing.This paper presented our study on the printability of 3D printed ADM scaffolds,with a focus on identifying the influence of printing parameters/conditions on printability.To characterize the printability,we examined the fiber morphology,pore size,strand diameter,and mechanical property of the printed scaffolds.Our results revealed that the printability could be affected by a number of factors and among them,the most considerable one was related to the nozzle diameter and the composition of ADM.We then evaluated the biocompatibility in terms of cytotoxicity,cell proliferation and vivisection.In vitro evaluation of the ADM scaffolds was carried out and the experimental results indicated that cells were viable and proliferative during the period of study.In vivo results also indicated that the defect area was well repaired without any noticeable infection,hematoma and other conditions.In conclusion,ADM could be reconstructed with 3D printing technology and ADM biological scaffold has potential applications for tissue engineering.
基金the funding support from the CityU New Research Initiatives/Infrastructure Support from Central under Grant APRC-9610426the State Key Laboratory of Marine Pollution (SKLMP) Seed Collaborative Research Fund under SKLMP/SCRF/0021。
文摘The discovery of laser-induced graphene(LIG) from polymers in 2014 has aroused much attention in recent years.A broad range of applications,including batteries,catalysis,sterilization,and separation,have been explored.The advantages of LIG technology over conventional graphene synthesis methods are conspicuous,which include designable patterning,environmental friendliness,tunable compositions,and controllable morphologies.In addition,LIG possesses high porosity,great flexibility,and mechanical robustness,and excellent electric and thermal conductivity.The patternable and printable manufacturing process and the advantageous properties of LIG illuminate a new pathway for developing miniaturized graphene devices.Its use in sensing applications has grown swiftly from a single detection component to an integrated smart detection system.In this minireview,we start with the introduction of synthetic efforts related to the fabrication of LIG sensors.Then,we highlight the achievement of LIG sensors for the detection of a diversity of stimuli with a focus on the design principle and working mechanism.Future development of the techniques toward in situ and smart detection of multiple stimuli in widespread applications will be discussed.
基金the CSIRO Low Emissions Technologies Program for the support of this studythe financial support from the Australian Research Council(ARC)for the Future Fellowship(FT130101337)+4 种基金QUT core funding(QUT/322120-0301/07)supported by NSF MRI(1428992)U.S.-Egypt Science and Technology(S&T)Joint FundSDBoR R&D ProgramEDA University Center Program(ED18DEN3030025)。
文摘Perovskite-based photovoltaic materials have been attracting attention for their strikingly improved performance at converting sunlight into electricity.The beneficial and unique optoelectronic characteristics of perovskite structures enable researchers to achieve an incredibly remarkable power conversion efficiency.Flexible hybrid perovskite photovoltaics promise emerging applications in a myriad of optoelectronic and wearable/portable device applications owing to their inherent intriguing physicochemical and photophysical properties which enabled researchers to take forward advanced research in this growing field.Flexible perovskite photovoltaics have attracted significant attention owing to their fascinating material properties with combined merits of high efficiency,light-weight,flexibility,semitransparency,compatibility towards roll-to-roll printing,and large-area mass-scale production.Flexible perovskite-based solar cells comprise of 4 key components that include a flexible substrate,semi-transparent bottom contact electrode,perovskite(light absorber layer)and charge transport(electron/hole)layers and top(usually metal)electrode.Among these components,interfacial layers and contact electrodes play a pivotal role in influencing the overall photovoltaic performance.In this comprehensive review article,we focus on the current developments and latest progress achieved in perovskite photovoltaics concerning the charge selective transport layers/electrodes toward the fabrication of highly stable,efficient flexible devices.As a concluding remark,we briefly summarize the highlights of the review article and make recommendations for future outlook and investigation with perspectives on the perovskite-based optoelectronic functional devices that can be potentially utilized in smart wearable and portable devices.
文摘Formation of copper wiring on a polyimide film by laser irradiation to a stable copper-complex film consisting of glyoxylic acid copper complex and methylamine copper complex in air has been investigated. A stable metallic copper on the polyimide film was precipitated even in air. Since this copper was generated only in the laser-irradiated parts, direct patterning of copper wiring was possible. It was also found that copper was precipitated by electroless copper plating on the laser-deposited copper wiring and it was possible to thicken the copper wiring by this precipitation. The resistivity of the copper wiring was almost the same as that of the bulk of metallic copper. The developed method—combining laser irradiation to a copper-complex-coated film and electroless copper plating—enables the high-speed deposition of fine copper wiring on a polyimide film in air by a printing process, indicating an inexpensive and useful process for fabricating copper wiring without high vacuum facility and heat-treatment under inert gas.
