Search

Natural leather with outstanding biomimetic properties is the main application of animal skin. However, the traditional tannery industry is facing serious issues of sustainability, such as low value addition and high environmental pollution. Upscaled functional leather (UFL) inherits all the natural properties of leather and combines it with other cross-domain functions, due to which it has gained considerable attention as advanced functional bio-based materials. This review briefly introduces the multi-hierarchical structure and preponderant properties of leather as a natural biomass. Further emphasis is on UFL, which includes electromagnetic (EM) wave absorbing leather, infrared absorbing leather, X-ray shielding leather, flexible conductive leather, flame-retardant leather, antibacterial leather, self-cleaning leather as well as water-, oil-, and soil-repellent leather. Furthermore, the fabrication methods of these UFLs, their merits and their respective applications are comprehensively discussed. Moreover, possible challenges and outlooks for the development of UFL are proposed. This review describes how UFL will expand the scope of applications and significantly improve the ontological value of natural leather. Significantly, UFL is expected to boost the sustainable development of conventional leather industry and the next-generation of advanced functional bio-based materials.

The research of self-healable polymers intended for medical use has increased in the last 20 years. These materials can self-repair and recover their functionality after damage; thus, they are of significant interest in diverse academic areas, including the biomedical field. In this regard, numerous synthetic and natural polymers are being used to develop self-healing hydrogels for tissue engineering applications, particularly for the restoration of bones, cartilage, skin, and even the central nervous system. These materials possess distinct advantages; for example, natural polymers are usually biocompatible and biodegradable, whereas synthetic polymers could be more suitable when rigid hydrogels with fast kinetics are required. Moreover, the intrinsic reticular matrix of these self-healing systems allows the load of diverse drugs and their controlled release. Remarkably, polymers may be mixed to obtain hydrogels with enhanced mechanical and biological properties. The elaboration of self-healable hydrogels is carried out through either covalent crosslinking or non-covalent crosslinking; the selection of the method depends on many factors, including the required mechanical properties and desired use. Although some articles have reviewed self-healing hydrogels, papers focused on utilizing these systems in tissue engineering are scarce. In this article, we perform a concise description of fabrication methods of self-healing hydrogels and the employed polymers. Furthermore, we provide numerous examples of hydrogels intended for biomedical purposes and discuss their key functional properties. Our main objective was to point out the most recent progress in utilizing self-healing polymers in tissue engineering.

Remarkable advances in nanomaterials and nanotechnology have led researchers in various fields. The scale effects imparted by nanomaterials are associated with unexpected macroscale phenomena and properties that find many applications. However, multi-functionalization may be accompanied by physical and commercial limitations. Therefore, research must proceed in several different directions. Here, we define multi-functionalization and the electrical applications thereof in terms of increasing performance, addition of new and valuable properties, and multi-physics in play. We deal with sensors, actuators, energy harvesters, and solar cells and explore research that seeks to increase sensitivity, append “stretchability”, and facilitate untethered communication. Furthermore, we analyze research trends in materials use and manufacturing, and highlight useful fabrication methods. With the aim of predicting future research trends, our review presents a roadmap that will aid research on sensing and multi-functional applications.

Inducing plasmonic characteristics, primarily localized surface plasmon resonance (LSPR), in conventional AuNPs through particle size and shape controlling could lead to significant enhancement in electrical, electrochemical, and optical properties. Synthetic protocols and versatile fabrication methods play pivotal roles to produced plasmonic gold nanoparticles (AuNPs), which can be employed in multipurpose energy, environmental and biomedical applications. The main focus of this review is to provide a comprehensive and tutorial overview of various synthetic methods to design highly plasmonic AuNPs, along with a brief essay to understand the experimental procedure for each technique. The latter part of the review is dedicated to the most advanced and recent solar-induced energy, environmental and biomedical applications. The synthesis methods are compared to identify the best possible synthetic route, which can be adopted while employing plasmonic AuNPs for a specific application. The tutorial nature of the review would be helpful not only for expert researchers but also for the novices in the field of nanomaterial synthesis and utilization of plasmonic nanomaterials in various industries and technologies.

With the rapid improvements in nanomaterials and imaging technology, great progresses have been made in diagnosis and treatment of diseases during the past decades. Fe3O4 magnetic nanoparticles (MNPs) with good biocompatibility and superparamagnetic property are usually used as contrast agent for diagnosis of diseases in magnetic resonance imaging (MRI). Currently, the combination of multiple imaging technologies has been considered as new tendency in diagnosis and treatment of diseases, which could enhance the accuracy and reliability of disease diagnosis and provide new strategies for disease treatment. Therefore, novel contrast agents used for multifunctional imaging are urgently needed. Fe3O4 MNPs are believed to be a potential candidate for construction of multifunctional platform in diagnosis and treatment of diseases. In recent years, there are a plethora of studies concerning the construction of multifunctional platform presented based on Fe3O4 MNPs. In this review, we introduce fabrication methods and modification strategies of Fe3O4 MNPs, expecting great improvements for diagnosis and treatment of diseases in the future.

Bio-nanochannels in living organisms participate in the physiological activities by selectively transporting ions through cell membranes. The structure and function of biological ion channels inspire the development of artificial ion nanochannels with practical applications. The bioinspired nanochannels based on polymer materials present good mechanical stability, high-performance ion transport and designability, which have attracted much attention. In this review, we mainly focus on the fabrication and application of polymer-based biomimetic nanochannels especially in environmentally responsive biosensor and energy conversion. We firstly introduce the basic understanding of nanochannels in ion regulation and osmotic energy conversion. Then, we discuss the fabrication methods of polymer-based nanochannels and highlight their advantages compared with other materials. The practical applications of polymer-based biomimetic nanochannels, especially in energy conversion and environmentally responsive biosensor, are detailedly discussed. Finally, we summarize the unsolved problems in bioinspired nanochannels and overview the further developing direction in this field.

Typical organization of science and mathematics K12 education divides subjects into discrete courses. However, science and engineering are highly interdisciplinary fields. To better equip students to engage in the interdisciplinary nature of real-world STEM research and practice, projects can be used to highlight the interconnectivity of core subjects. Here, we present an exploratory, guided inquiry classroom research project. This work details student-led experiments combining physics and chemistry principles to fabricate silicone bouncy balls and analyze resulting mechanochemical relationships in these elastomeric materials. In this project, students embodied researchers to uncover foundational relationships among chemistry, physics, and mathematics. To do this, students used silicone kits to design an array of polymer formulations resulting in bouncy balls of varying stiffnesses. Students aimed to answer a physics-based research question using chemistry and mathematics. The resulting data was used to discuss the effect of polymer chemistry on the behavior of the bouncy balls. This exercise serves to combine hands-on fabrication methods with quantitative analysis, using experimental methods of varying costs and complexities that can be tailored to instructor time and budget. The project presented here is appropriate for upper-level high school students or first-year undergraduates. The pedagogical goal of the work is to empower students to realize and use connections between chemistry, physics, polymer science, and engineering to understand the process of material design and selection.

Two-dimensional (2D) materials have emerged as a class of promising materials to prepare highperformance 2D membranes for various separation applications. The precise control of the interlayer nano-channel/sub-nanochannel between nanosheets or the pore size of nanosheets within 2D membranes enables 2D membranes to achieve promising molecular sieving performance. To date, many 2D membranes with high permeability and high selectivity have been reported, exhibiting high separation performance. This review presents the development, progress, and recent breakthrough of different types of 2D membranes, including membranes based on porous and non-porous 2D nanosheets for various separations. Separation mechanism of 2D membranes and their fabrication methods are also reviewed. Last but not the least, challenges and future directions of 2D membranes for wide utilization are discussed in brief.

FGMs are a specific class of composites in which materials are graded as per applications. The original idea of the compositional and structural gradient in material microstructure was first proposed for polymeric and composite materials in 1972. This paper focuses on the solid-state processing techniques of the functionally graded materials, gradation, and their application in various fields. Type of gradation, application, the combination of material, and their associated fabrication parameters are presented in tabular form which has been used by different authors which will help readers to identify the best combination of material, based on their requirements. Further, Voigt and MORI- Tanaka models used for theoretical analysis for measurement of effective properties of FGMs are also presented. Usually, the majority of the literature work has a place with the gradation of metal-ceramic material cocktail created utilizing PM procedure is accessible and their outcome uncovers improved mechanical properties contrasted with materials in pure form.

Lab-on-paper, or microfluidic paper-based analytical devices (μPADs), use paper as a substrate material, and are patterned with a system of microchannels, reaction zones and sensing elements to perform analysis and detection. The sample transfer in such devices is performed by capillary action. As a result, external driving forces are not required, and hence the size and cost of the device are significantly reduced. Lab-on-paper devices have thus attracted significant attention for point-of-care medical diagnostic purposes in recent years, particularly in less-developed regions of the world lacking medical resources and infrastructures. This review discusses the major advances in lab-on-paper technology for blood analysis and diagnosis in the past five years. The review focuses particularly on the many clinical applications of lab-on-paper devices, including diabetes diagnosis, acute myocardial infarction (AMI) detection, kidney function diagnosis, liver function diagnosis, cholesterol and triglyceride (TG) analysis, sickle-cell disease (SCD) and phenylketonuria (PKU) analysis, virus analysis, C-reactive protein (CRP) analysis, blood ion analysis, cancer factor analysis, and drug analysis. The review commences by introducing the basic transmission principles, fabrication methods, structural characteristics, detection techniques, and sample pretreatment process of modern lab-on-paper devices. A comprehensive review of the most recent applications of lab-on-paper devices to the diagnosis of common human diseases using blood samples is then presented. The review concludes with a brief summary of the main challenges and opportunities facing the lab-on-paper technology field in the coming years.

To promote the development of supercapacitors and their applications in modern electronics, it is crucial to explore novel supercapacitor electrode materials. As a representative member of the rising 2D MXenes, Ti3C2Tx MXene has shown tremendous potential for supercapacitor electrodes owing to its unique physicochemical properties. Here, the most recent advances in Ti3C2Tx-based supercapacitor electrodes are comprehensively reviewed, with an emphasis on the vital role that Ti3C2Tx MXene plays in the remarkable electrochemical performance and related mechanisms. The fabrication methods, electrode structures, working mechanisms, electrochemical performance and related influencing factors, mechanical properties and applications, as well as the associated advantages/disadvantages of Ti3C2Tx-based supercapacitor electrodes are thoroughly and exhaustively summarized and discussed. Based on the recent progress, the existing challenges along with the corresponding possible solutions, and the future prospects of Ti3C2Tx-based materials for supercapacitors are also outlined and discussed.

Yarn-based strain sensor is an emerging candidate for the fabrication of wearable electronic devices. The intrinsic properties of yarn, such as excellent lightweight, flexibility, stitchability, and especially its highly stretchable performance, stand out the yarn-based strain sensor from conventional rigid sensors in detection of human body motions. Recent advances in conductive materials and fabrication methods of yarn-based strain sensors are well reviewed and discussed in this work. Coating techniques including dip-coating, layer by layer assemble, and chemical deposition for deposition of conductive layer on elastic filament were first introduced, and fabrication technology to incorporate conductive components into elastic matrix via melt extrusion or wet spinning was reviewed afterwards. Especially, the recent advances of core–sheath/wrapping yarn strain sensor as-fabricated by traditional spinning technique were well summarized. Finally, promising perspectives and challenges together with key points in the development of yarn strain sensors were presented for future endeavor.

Owing to the expanding world of materials, there appears an intelligible and timely need for the development of materials that are easily fabricable, light in weight and have greatly enhanced properties in comparison with the conventional ones. A quick glance on foams, alluding a cellular closed structure, depicts remarkable combination of optimized material utilization for high strength and low density. Aluminium, being commonly available and light weighted, under controlled processing, offers substantial advantages for the evolution of improved materials. Aluminium Syntactic Foams (ASFs) are the composites having aluminium matrix with usually pre-formed inorganic hollow spherical reinforcements arranged in an orderly fashion with constituents of either metallic, polymeric or ceramic nature, or superfluous byproducts. These spherical reinforcements impart high strength to the syntactic foams and compensate the lower hardness and stiffness of aluminium. Several researches have been done for developing lightweight materials. Liquid route has proven highly effective over the solid-state methods for fabrication of lightweight materials. Dispersion mechanisms are adopted by various liquid route fabrication methods offering uniform distribution of reinforcements within the aluminium matrix. With focus on Aluminium Syntactic Foams (ASFs), these fabrication methods are broadly classified in the current study and, their constructive effects on properties are a summarized and scrutinized on the basis of ongoing explorations being conducted across the world.

OLEDs have become prominent in commercial display and lighting applications, mainly for television and smartphone screens, and in many electronic gadgets due to superior features over other display technologies such as Liquid Crystal Displays (LCDs). In the evolution of OLED fabrication, roll-to-roll (R2R) solution-based techniques, which are low-cost and high throughput, have emerged as next-generation manufacturing methods for OLED production. Researchers and scientists all over the world are investigating R2R upscaling methods. Thus far, the existing R2R fabrication methods for manufacturing high performance OLEDs have had limited success due to film thickness variations, aggregation in films, challenges in forming the multi-layer structure, and scarcity of efficient interlayers. Slot-die coating is a very promising fabrication technique that can facilitate R2R manufacturing of OLEDs and address some of the aforementioned challenges. In this review, a summary of the developments in OLED fabrication using slot-die coating methods is presented. First, we highlight the research work on the slot-die coating of single and multi-layer OLEDs, and then we present various modifications of slot-die heads to fabricate micro-sized OLEDs for high-resolution display applications. Lastly, we present a qualitative comparison between the performance of OLEDs fabricated by slot-die coating and the ones fabricated by other R2R techniques. While many review articles have been published on OLED materials and devices, there is not one collection of reports detailing the slot-die coating, an additive manufacturing method, of OLEDs.

Unidirectional liquid transport without any need of external energy has drawn worldwide attention for its potential applications in various fields such as microfluidics, biomedicine and mechanical engineering. In nature, numerous creatures have evolved such extraordinary unidirectional liquid transport ability, such as spider silk, Sarracenia’s trichomes, and Nepenthes alata’s peristome, etc. This review summarizes the current progresses of natural unidirectional liquid transport on 1-Dimensional (1D) linear structure and 2-Dimensional (2D) surface structure. The driving force of unidirectional liquid transport which is determined by unique structure exist distinct differences in physics. The fundamental understanding of 1D and 2D unidirectional liquid transport especially about hierarchical structural characteristics and their transport mechanism were concentrated, and various bioinspired fabrication methods are also introduced. The applications of bioinspired directional liquid transport are demonstrated especially in fields of microfluidics, biomedical devices and anti-icing surfaces. With newly developed smart materials, various liquid transport regulation strategies are also summarized for the control of transport speed, direction guiding, etc. Finally, we provide new insights and future perspectives of the directional transport materials.

The study presents general aspects of highly dispersed nano scale materials including their origins, structure, classification, properties and production methods. In the last two decades, the unique properties and phenomena observed for those material has revolutionized the industry with a significant increase in research and the scope of practical applications of nanotechnology in every aspect of our lives.

Micro-nanoscale core–shell particles are distinguishable from other particle types because of their unique composition. Core-shell particles combine the features of both the core and shell materials, while exhibiting smart properties resulting from their materials. In the past few years, the research community has paid increasing attention to the generation and application of core–shell structures. The present review focuses on the core–shell microparticles, which have found practical applications in various fields. The novel properties of the core–shell microparticles make them extremely suitable for pharmaceutical and biomedical applications, including cell encapsulation, cell study, targeted drug delivery, controlled drug release, food industry, catalysis, and environmental monitoring. This paper also systematically reviews the different classes of core–shell microparticles based on their respective materials. Moreover, an overview of conventional and more recent microfluidic methods for the generation of core–shell microparticles is presented. The unique advantages of the microfluidic approaches are highlighted.

This article aims to provide a comprehensive review of recent advances in the use of gas-phase synthesized nanoparticles in the field of sensing technology. Since there are numerous and diverse reviews that already cover the subject extensively, this review focuses predominantly but not exclusively on gas-phase synthesized metallic nanoparticles and their most prominent sensing-applications. After a brief overview on the main uses of nanoparticles in science and technology, as well as a description of the dominant fabrication methods, the review discusses their incorporation in strain-sensing, chemical sensing and bio-sensing as well as a few other sensing-applications. The review highlights the inherent advantages of nanoparticles, as well as how they combine with flexible gas-phase synthesis processes.

International audience; Chicken egg white is an abundant, inexpensive and natural source of important proteins such as ovalbumin and lysozyme. Thanks to its bioactivity, easy handling, anti-bacterial activity and biodegradability, egg white is being used since centuries as excipient of poultices for the treatment of various disorders. Owing to unique thermal and electrical features, egg white is currently used in bioplastic development and in fabrication of field-effect transistors, but it could also contribute to various biomedical applications in the future. Indeed, egg white and some of its byproducts were shown to improve tissue engraftment and to stimulate angiogenesis, making it particularly attractive in wound healing and tissue engineering applications. Moreover, egg white can be manipulated to obtain versatile platforms for tridimensional in vitro tissue models or drug delivery systems. This review describes the structure and physicochemical properties of egg white as well as its biological features. It also summarizes fabrication methods from egg white for the generation of functional platforms, and provides a comprehensive overview of the role and performance of egg white in various biomedical applications. Finally, new perspectives for future studies in health with this ancient material are critically discussed.

Because of their unique three-dimensional cellular structure and intrinsic properties, polyimide foam materials have bright prospects for development in multiple functional equipment, which arouses extensive concern. In this Spotlight on Applications, several typical fabrication methods of polyimide foams and the related synthesis mechanism have been systematically described. The advantages and disadvantages of the preparation methods have been compared with each other. Representative functions and the corresponding mechanism models have been concluded, which involve thermal, mechanical, sensing, electromagnetic, environmental, and electrical fields. In the end, the severe tasks and challenges of polyimide foam materials have been summarized, and their promising future development is worth expecting.

The development of magnetic two-dimensional (2D) materials in its infancy has generated an enormous amount of attention as it offers an ideal platform for the exploration of magnetic properties down to the 2D limit, paving the way for spintronic devices. Due to the nonnegligible advantages including time efficiency and simplified process, the facile bottom-up chemical vapor deposition (CVD) is regarded as a robust method to fabricate ultrathin magnetic nanosheets. Recently, some ultrathin magnets possessing fascinating properties have been successfully synthesized via CVD. Here, the recent researches toward magnetic 2D materials grown by CVD are systematically summarized with special emphasis on the fabrication methods. Then, heteroatoms doping and phase transition induced in CVD growth to bring or tune the magnetic properties in 2D materials are discussed. Characterizations and applications of these magnetic materials are also discussed and reviewed. Finally, some perspectives in need of urgent attention regarding the development of CVD-grown magnetic 2D materials are proposed.

The availability of accessible fabrication methods based on deterministic transfer of atomically thin crystals has been essential for the rapid expansion of research into van der Waals heterostructures. An inherent issue of these techniques is the deformation of the polymer carrier film during the transfer, which can lead to highly non-uniform strain induced in the transferred two-dimensional material. Here, using a combination of optical spectroscopy, atomic force and Kelvin probe force microscopy, we show that the presence of nanometer scale wrinkles formed due to transfer-induced stress relaxation can lead to strong changes in the optical properties of MoSe$_2$/WSe$_2$ heterostructures and the emergence of the linearly polarized interlayer exciton photoluminescence. We attribute these changes to the local breaking of crystal symmetry in the nanowrinkles, which act as efficient accumulation centers for the interlayer excitons due to the strain-induced interlayer band gap reduction. The surface potential images of the rippled heterobilayer samples acquired using Kelvin probe force microscopy reveal the variation of the local work function consistent with the strain-induced band gap modulation, while the potential offset observed at the ridges of the wrinkles shows a clear correlation with the value of the tensile strain estimated from the wrinkle geometry. Our findings highlight the important role of the residual strain in defining optical properties of van der Waals heterostructures and suggest novel approaches for interlayer exciton manipulation by local strain engineering.

We report on a recent workshop dedicated to additive manufacturing (AM) of ceramics that was held at the National Institute of Standards and Technology (NIST) in November 2019. This two-day all-invited meeting brought together experts from industry, government agencies and academia to review the state of the field and identify the most pressing applied materials research and metrology issues which, if addressed, could accelerate the incorporation of AM methods into commercial ceramic manufacturing. Besides the AM technologies, the discussions included consideration of the necessary post-processing steps. We highlight some of the successes and challenges for the adoption of ceramics AM on an industrial scale, as viewed by the workshop participants. We also propose actions for the ceramic community to facilitate the wider commercialization of these fabrication methods.

Organic halogen-bonded co-crystals assembled from two or more components via halogen bonds, have attracted significant attention due to their unpredictable and outstanding chemical and physical properties, which make them potential candidate materials for organic optoelectronic applications. This paper briefly summarizes the recent progress in terms of the developed fabrication methods for organic halogen-bonded co-crystals and their multifunctional optoelectronic applications. Based on the current research on organic halogen-bonded co-crystals, we further discuss the achievements as well as the existing challenges. Finally, we provide our outlooks for further studies and applications of organic halogen-bonded co-crystals.

The most important topics in the world today are environmental and resource issues. The development of green and clean energy is still one of the great challenges of social sustainable development. Two-dimensional(2D) metal-organic frameworks(MOFs) and derivatives have exceptional potential as high-efficiency electrocatalysts for clean energy technologies. This review summarizes various synthesis strategies and applications of 2D MOFs and derivatives in electrocatalysis. Firstly, we will outline the advantages and uniqueness of 2D MOFs and derivatives, as well as their applicable areas. Secondly, the synthetic strategies of 2D MOFs and derivatives are briefly classified. Each category is summarized and we list classic representative fabrication methods, including specific fabrication methods and mechanisms, corresponding structural characteristics, and insights into the advantages and limitations of the synthesis method. Thirdly, we separately classify and summarize the application of 2D MOFs and derivatives in electrocatalysis, including electrocatalytic water splitting, oxygen reduction reaction(ORR), CO2 reduction reaction(CO2RR), and other electrocatalytic applications. Finally, the development prospects and existing challenges to 2D MOFs and derivatives are discussed.

Successful materials design for bone-tissue engineering requires an understanding of the composition and structure of native bone tissue, as well as appropriate selection of biomimetic natural or tunable synthetic materials (biomaterials), such as polymers, bioceramics, metals and composites. Scalable fabrication technologies that enable control over construct architecture at multiple length scales, including three-dimensional printing and electric-field-assisted techniques, can then be employed to process these biomaterials into suitable forms for bone-tissue engineering. In this Review, we provide an overview of materials-design considerations for bone-tissue-engineering applications in both disease modelling and treatment of injuries and disease in humans. We outline the materials-design pathway from implementation strategy through selection of materials and fabrication methods to evaluation. Finally, we discuss unmet needs and current challenges in the development of ideal materials for bone-tissue regeneration and highlight emerging strategies in the field. Design of bone-tissue-engineering materials involves consideration of multiple, often conflicting, requirements. This Review discusses these considerations and highlights scalable technologies that can fabricate natural and synthetic biomaterials (polymers, bioceramics, metals and composites) into forms suitable for bone-tissue-engineering applications in human therapies and disease models.

Responsive hydrogels that undergo controlled shape changes in response to a range of stimuli are of interest for microscale soft robotic and biomedical devices. However, these applications require fabrication methods capable of preparing complex, heterogeneous materials. Here we report a new approach for making patterned, multi-material and multi-responsive hydrogels, on a micrometre to millimetre scale. Nanolitre aqueous pre-gel droplets were connected through lipid bilayers in predetermined architectures and photopolymerized to yield continuous hydrogel structures. By using this droplet network technology to pattern domains containing temperature-responsive or non-responsive hydrogels, structures that undergo reversible curling were produced. Through patterning of gold nanoparticle-containing domains into the hydrogels, light-activated shape change was achieved, while domains bearing magnetic particles allowed movement of the structures in a magnetic field. To highlight our technique, we generated a multi-responsive hydrogel that, at one temperature, could be moved through a constriction under a magnetic field and, at a second temperature, could grip and transport a cargo.

The angle-variable tunable optical filter was strictly fabricated by two strategies of nanoimprint-coupled metal nanopatterning with improved cost-effectiveness and accessibility. The tunable optical properties and the performances of two strategies were experimentally examined and turned out to be well matched to numerical results. Tunable properties are obtained by three factors: size of fabricated Ag nanodisks, incident illumination angle, and fabrication strategies. The resonant extinction peak shifts were identified to show a large increase along with the increase in fabricated Ag disk size and increase in the incidence angle of illumination. When comparing a fabrication strategy, it was confirmed that the sample fabricated by the strip-off method has better stability on color changes with a consistent dependency on the incident angle. The presented strategies of fabrication are technically viable for obtaining well-defined plasmonic nanostructures so that it has the feasibility to apply for fascinating optical applications including display or tunable optical filters.

Generally, cracking occurs for many reasons connected to uncertainties and to the non-uniformity resulting from intrinsic deficiencies in materials or the non-linearity of applied external (thermal, mechanical, etc.) stresses. However, recently, an increased level of effort has gone into analyzing the phenomenon of cracking and also into methods for controlling it. Sophisticated manipulation of cracking has yielded various cutting-edge technologies such as transparent conductors, mechanical sensors, microfluidics, and energy devices. In this paper, we present some of the recent progress that has been made in controlling cracking by giving an overview of the fabrication methods and working mechanisms used for various mediums. In addition, we discuss recent progress in the various applications of methods that use controlled cracking as an alternative to patterning tools.

Two-dimensional (2D) materials with a nanoscale thickness are promising candidates for advanced molecular separations. MXenes are cutting-edge 2D materials, which have been extensively explored and applied in high performance molecular separations. Due to their remarkable flexibility, hydrophilic surface, high mechanical strength, and good electrical conductivity, the MXene family of materials has unique advantages in a wide range of membrane-based separation processes, such as gas separation, pervaporation, desalination, and solvent/water separation. In this review, recent advances in the design of MXene-based membranes and their applications in molecular separations are highlighted. The current synthetic strategies and structures of MXenes are described; based on these, the key parameters that affect the MXene properties are identified. Then, the fabrication methods of MXene-based membranes and their ground-breaking separation applications are reviewed. Despite the remaining challenges, the vigorous development of MXene materials offers a new avenue for the design of novel membranes for precise and effective separation.

Thermoresponsive polymers hold great potential in the biomedical field, since they enable the fabrication of cell sheets, in situ drug delivery and 3D-printing under physiological conditions. In this review we provide an overview of several thermoresponsive polymers and their application, with focus on poly(N-isopropylacrylamide)-surfaces for cell sheet engineering. Basic knowledge of important processes like protein adsorption on surfaces and cell adhesion is provided. For different thermoresponsive polymers, namely PNIPAm, Pluronics, elastin-like polypeptides (ELP) and poly(N-vinylcaprolactam) (PNVCL), synthesis and basic chemical and physical properties have been described and the mechanism of their thermoresponsive behavior highlighted. Fabrication methods of thermoresponsive surfaces have been discussed, focusing on PNIPAm, and describing several methods in detail. The latter part of this review is dedicated to the application of the thermoresponsive polymers and with regard to cell sheet engineering, the process of temperature-dependent cell sheet detachment is explained. We provide insight into several applications of PNIPAm surfaces in cell sheet engineering. For Pluronics, ELP and PNVCL we show their application in the field of drug delivery and tissue engineering. We conclude, that research of thermoresponsive polymers has made big progress in recent years, especially for PNIPAm since the 1990s. However, manifold research possibilities, e.g. in surface fabrication and 3D-printing and further translational applications are conceivable in near future.

Investigations on superhydrophobic surfaces (SHS) are very interesting because of their importance in many applications. One of the major applications of these SHS is to increase the corrosion resistance of surfaces exposed to corrosive environments as well as their long-term chemical stability and maintaining the superhydrophobic characteristics. Deep understanding of how to increase the corrosion resistance by SHS has a significant effect on the development of strategies to improve corrosion resistance and long-term chemical stability of these surfaces. Other important properties that limited the real use of superhydrophobic surfaces are mechanical stability. In this review article, an overview of SHS is provided, and then their fabrication methods discussed. Moreover, the corrosion resistance of these SHS fabricated by various methods and their chemical stability and mechanical stability are reviewed. -In the following, recent strategies for improvement of corrosion resistance, chemical and mechanical stability are reviewed. Keywords: Chemical durability, Corrosion resistance, Mechanical stability, Superhydrophobic surfaces

New magnetic materials for energy and information-processing applications are of paramount importance in view of significant global challenges in environmental and information security. The discovery and design of materials requires efficient computational and experimental approaches for high throughput and efficiency. When increasingly powerful computational techniques are combined with special non-equilibrium fabrication methods, the search can uncover metastable compounds with desired magnetic properties. Here we review recent results on novel Fe-, Co- and Mn-rich magnetic compounds with high magnetocrystalline anisotropy, saturation magnetization, and Curie temperature created by combining experiments, adaptive genetic algorithm searches, and advanced electronic-structure computational methods. We discuss structural and magnetic properties of such materials including Co– and/or Fe–X compounds (X = N, Si, Sn, Zr, Hf, Y, C, S, Ti, or Mn), and their prospects for practical applications.

This paper describes a method to fabricate microfluidic paper-based analytical devices (μPADs) using a toner laser printer. Multiple methods have been reported for the fabrication of μPADs for point-of-care diagnostics and environmental monitoring. Despite successful demonstrations, however, existing fabrication methods depend on particular printers, in-house instruments, and synthetic materials. In particular, recent discontinuation of the solid wax printer has made it difficult to fabricate μPADs with readily available instruments. Herein we reported the fabrication of μPADs using the most widely available type of printer: a toner laser printer. Heating of printed toner at 200 °C allowed the printed toner to reflow, and the spreading of the hydrophobic polymer through the filter paper was characterized. Using the developed μPADs, we conducted model colorimetric assays for glucose and bovine serum albumin (BSA). We found that heating of filter paper at 200 °C for 60 min caused the pyrolysis of cellulose in the paper. The pyrolysis resulted in the formation of aldehydes that could interfere with molecular assays involving redox reactions. To overcome this problem, we confirmed that the removal of the aldehyde could be readily achieved by washing the μPADs with aqueous bleach. Overall, the developed fabrication method should be compatible with most toner laser printers and will make μPADs accessible in resource-limited circumstances.

With the continuous deterioration of the electromagnetic environment, there is an urgent need for exploring highly efficient and widely applicable electromagnetic interference shielding and microwave absorption materials. In current years, wood-based composites have been vastly investigated with low cost, light weight, sustainability, and an inherent porous and hierarchical structure. However, imperfect interfacial compatibility and electrical conductivity of wood are the main factors, which result in inferior electromagnetic interference shielding and microwave absorption performances. Meanwhile, the intrinsic defects of wood such as rotting and flammability also limit their practical applications. To overcome these shortcomings, improving the combination of each phase unit in micro–nano size and exploiting multi-functional composites are feasible solutions to optimize the electromagnetic properties of wood-based materials. In this review, the basic principles and mechanisms of electromagnetic interference shielding and microwave absorption are introduced comprehensively. Meanwhile, various wood-based electromagnetic interference shielding, microwave absorption composites, and their fabrication methods are discussed in detail. Furthermore, the perspectives and challenges in this field are put forth as well.

Increasing awareness for sustainability has led to the development of smart self-healing materials, which can extend the service life and improve safety without human intervention. Vascular networks are observed in biological systems, such as leaf venation and blood vascular systems, and provide inspiration for self-healing mechanisms in engineered systems. Embedding a vascular network in a host material has the advantage of addressing varying magnitudes of damage and allowing for an indefinite replenishment of the healing agent, which are current limitations of intrinsic and capsule-based self-healing systems. These networks are demonstrated in polymer and composite materials, with fabrication methods including removal of sacrificial elements, electrospinning, and an array of additive manufacturing (AM) techniques. Advances in AM allow more complex network configurations to be realized that optimize fluid distribution and healing potential. This review intends to provide a comprehensive overview of the current progress and limitations of the design approaches, fabrication methods, healing mechanisms, and relevant applications of embedded vascular networks. Additionally, significant research gaps and future research directions for vascular self-healing materials are described.

International audience; Carbon Nanomaterials present many exceptional properties, including antimicrobial ones. The transfer of the latter through their incorporation into materials has generated a growing interest with a significant increase in number of publications since 2011. The use of polymeric matrices presents many advantages, because polymers are efficient nanoparticles holders and also exhibit intrinsic antimicrobial properties in some cases. The state of the art of fabrication methods and presumed antimicrobial mechanism is presented, focusing on antibacterial activity as the latter is, by far, the most discussed in the literature. Even if many examples of such nanocomposites are available, most of them correspond to carbon nanomaterials incorporated in the volume, while only the surface is of interest in terms of intrinsic (and thus expected long-term) activity, and there is still a lack of information concerning the occurring antimicrobial mechanisms. We have identified the good stability of carbon nanomaterials in biological environment as an interesting option in terms of durability of the antimicrobial effect and will discuss this question in detail, as well as the fact that there are currently no clear conclusions concerning toxicity aspects due to the possible release of such nanoparticles in use conditions.

In recent years, microfluidic lab-on-paper devices have emerged as a rapid and low-cost alternative to traditional laboratory tests. Additionally, they were widely considered as a promising solution for point-of-care testing (POCT) at home or regions that lack medical infrastructure and resources. This review describes important advances in microfluidic lab-on-paper diagnostics for human health monitoring and disease diagnosis over the past five years. The review commenced by explaining the choice of paper, fabrication methods, and detection techniques to realize microfluidic lab-on-paper devices. Then, the sample pretreatment procedure used to improve the detection performance of lab-on-paper devices was introduced. Furthermore, an in-depth review of lab-on-paper devices for disease measurement based on an analysis of urine samples was presented. The review concludes with the potential challenges that the future development of commercial microfluidic lab-on-paper platforms for human disease detection would face.

Funding Information: Funding: The authors gratefully acknowledge the funding from Academy of Finland BESIMAL project (decision number 334197). J.W. also acknowledges the funding from Jenny and Antti Wihuri Foundation. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. Innovations in industrial automation, information and communication technology (ICT), renewable energy as well as monitoring and sensing fields have been paving the way for smart devices, which can acquire and convey information to the Internet. Since there is an ever-increasing demand for large yet affordable production volumes for such devices, printed electronics has been attracting attention of both industry and academia. In order to understand the potential and future prospects of the printed electronics, the present paper summarizes the basic principles and conventional approaches while providing the recent progresses in the fabrication and material technologies, applications and environmental impacts.

Polyelectrolyte multilayers are versatile materials that are used in a large number of domains, including biomedical and environmental applications. The fabrication of polyelectrolyte multilayers using the layer-by-layer technique is one of the simplest methods to obtain composite functional materials. The properties of the final material can be easily tuned by changing the deposition conditions and the used building blocks. This review presents the main characteristics of polyelectrolyte multilayers, the fabrication methods currently used, and the factors influencing the layer-by-layer assembly of polyelectrolytes. The last section of this paper presents some of the most important applications of polyelectrolyte multilayers, with a special focus on biomedical and environmental applications.

In the past few decades, NAND flash memory has been one of the most successful nonvolatile storage technologies, and it is commonly used in electronic devices because of its high scalability and reliable switching properties. To overcome the scaling limit of planar NAND flash arrays, various three-dimensional (3D) architectures of NAND flash memory and their process integration methods have been investigated in both industry and academia and adopted in commercial mass production. In this paper, 3D NAND flash technologies are reviewed in terms of their architecture and fabrication methods, and the advantages and disadvantages of the architectures are compared.

Electrically responsive biomaterials are an important and emerging technology in the fields of biomedical and material sciences. A great deal of research explores the integral role of electrical conduction in normal and diseased cell biology, and material scientists are focusing an even greater amount of attention on natural and hybrid materials as sources of biomaterials which can mimic the properties of cells. This review establishes a summary of those efforts for the latter group, detailing the current materials, theories, methods, and applications of electrically conductive biomaterials fabricated from protein polymers and polysaccharides. These materials can be used to improve human life through novel drug delivery, tissue regeneration, and biosensing technologies. The immediate goal of this review is to establish fabrication methods for protein and polysaccharide-based materials that are biocompatible and feature modular electrical properties. Ideally, these materials will be inexpensive to make with salable production strategies, in addition to being both renewable and biocompatible.

Chitin/chitosan research is an expanding field with wide scope within polymer research. This topic is highly inviting as chitin/chitosan’s are natural biopolymers that can be recovered from food waste and hold high potentials for medical applications. This review gives a brief overview of the chitin/chitosan based nanomaterials, their preparation methods and their biomedical applications. Chitin nanofibers and Chitosan nanofibers have been reviewed, their fabrication methods presented and their biomedical applications summarized. The chitin/chitosan based nanocomposites have also been discussed. Chitin and chitosan nanofibers and their binary and ternary composites are represented by scattered superficial reports. Delving deep into synergistic approaches, bringing up novel chitin/chitosan nanocomposites, could help diligently deliver medical expectations. This review highlights such lacunae and further lapses in chitin related inputs towards medical applications. The grey areas and future outlook for aligning chitin/chitosan nanofiber research are outlined as research directions for the future.

In many clinical applications, the transdermal route is used as an alternative approach to avoid the significant limitations associated with oral drug delivery. There is a long history for drug delivery through the skin utilizing transdermal microneedle arrays. Microneedles are reported to be versatile and very efficient devices. This technique has spurred both industrial and scientific curiosity, due to its outstanding characteristics such as painless penetration, affordability, excellent medicinal efficiency, and relative protection. Microneedles possess outstanding properties for diverse biomedical uses such as the delivery of very large substances with ionic and hydrophilic physicochemical properties. Importantly, microneedles are applicable in numerous biomedical fields such as therapy, diagnosis, and vaccine administration. Microneedles are emerging tools that have shown profound potential for biomedical applications. Transdermal microneedle technologies are likely to become a preferred route of therapeutic substances administration in the future since they are effective, painless, and affordable. In this review, we summarize recent advances in microneedles for therapeutic applications. We explore their constituent materials and fabrication methods that improve the delivery of critical therapeutic substances through the skin. We further discuss the practicality of advanced microneedles used as drug delivery tools.

Solid-state mechanochemical approach to copolymer synthesis is a promising way to produce macromolecules combining properties and advantages of polymers of different nature. In addition to high efficiency and ecological benefits this synthetic route allows producing a relatively high amount of copolymers, which makes fabrication of the copolymer-based materials reasonable. Synthesis of amphiphilic natural/synthetic copolymers is especially promising in terms of their further use for formation of advanced materials for various applications, especially for biomedicine. This study highlights an effect of hydrophilic-hydrophobic balance of complex protein-contained chitosan-g-oligo-/polylactide copolymers on possibility to apply a range of material fabrication methods.

This mini review is devoted to analysis of the latest advances in the development of aluminum-based composite materials (CMs) reinforced by microstructures and nanostructures. The fabrication methods of CMs, various reinforcing additives (Al2O3, AlN, SiC, CuO, B4C, Li3N, C, and BN), and their morphological types (nanotubes, nanoplates, microparticles, and nanoparticles), as well as the structure and properties of CMs, are considered. The importance of theoretical modeling methods for studying the strength of interfaces in CMs is shown.

Architected materials play an essential role in achieving next-generation electrochemical systems with unprecedented power and energy capabilities. The geometry and chemistry of architected materials can be engineered to address key areas of performance, including electrochemical kinetics and mechanics. Electrochemical kinetics impact key metrics such as power density, efficiency, and lifetime in batteries, fuel cells, and sensors. Additionally, electrochemical reactions can dramatically change material composition, which may result in large strains (in the hundreds of percent) that cause mechanical failure. In this article, we summarize advances in energy storage offered by architected materials and highlight fabrication methods used to realize these advances. We also discuss electrochemistry as an enabling tool for architected materials with functionality beyond energy storage and sensing.

Preparation of high-quality films plays an important role to achieve high-performance nonfullerene (NF) organic solar cells. NF active layer films are typically fabricated by spin coating. Novel fabrication methods to process the NF active layer are desirable to be compatible with large-area production. Herein, we report on the fabrication of NF active layer films via a water transfer printing method. This method delivers a uniform film with controllable film thicknesses. NF active layers of PDBD-T:ITIC and PBDB-T-2F:IT-4F were fabricated via the method to validate its effectiveness. Solar cells with the water transfer-printed active layers show comparable performance (up to 11.7%) to the cells with spin-coated active layers. Furthermore, NF solar modules containing 4-sub cells with the active area of 3.2 cm2 are also fabricated via the method. The module shows VOC of up to 3.4 V and a power conversion efficiency of 8.1% with the PBDB-T-2F:IT-4F active layer.

Bacterial cellulose (BC) is an extracellular natural polymer produced by many microorganisms and its properties could be tailored via specific fabrication methods and culture conditions. There is a...

Solid-state nanopore in analytical chemistry has developed rapidly in the 1990s and it is proved to be a versatile new tool for bioanalytical chemistry. The research field of solid-state nanopore starts from mimicking the biological nanopore in living cells. Understanding the transport mechanism of biological nanopore in vivo is a big challenge because of the experimental difficulty, so it is essential to establish the basic research of artificial nanopores in vitro especially for the analysis of ions and small molecules. The performance of solid-state nanopores could be evaluated by monitoring currents when ions and molecules passed through. The comparison of the two types of nanopores based on current-derived information can reveal the principle of biological nanopores, while the solid-state nanopores are applied into practical bioanalysis. In this review, we focus on the researches of the solid-state nanopores in the fabrication process and in the analysis of ions and small molecules. Fabrication methods of nanopores, ion transport mechanism, small molecule analysis and theoretical studies are discussed in detail.