Innovative Fabrication Research Articles

Recent Trends in Microencapsulation for Smart and Active Innovative Textile Products

Authors would like to acknowledge the Spanish Ministry of Economy and Competitiveness for financial support (Refs. MAT2014-59242-C2-2-R and MAT2014-55778-REDT).

An Innovative Light Trapping Structure Fabrication Method on Diamond‐Wire‐Sawing Multi‐Crystalline Silicon Wafers

AbstractAn innovative fabrication method of light trapping structures on the surface of diamond‐wire‐sawing multi‐crystalline silicon (DWS mc‐Si) is proposed, which may trigger new progress in photovoltaic (PV) industry. A simple pre‐etching step with HNO3/HF solution is used to remove the saw marks of the wafers as well as amorphous silicon layers, and form vermicular micro‐hollows. Then, the HNO3/HF fog formed by ultrasonic vibration etches the silicon surface to fabricate nano‐scale porous structures on the above microstructures. This micro‐nano composite structure (MNCS) surface shows low average light reflectivity (∼5.5%) and relatively higher effective minority carrier lifetime (∼5.2 μs). The innovative method is applied to fabricate the 156 mm × 156 mm DWS mc‐Si solar cells and the conversion efficiency of 18.01% has been obtained, which is 0.93% higher than the cells without MNCS. This method matches well with current PV industrial processes, which shows a promising prospect.

Stars, Stripes, and the Streamlined Body

This article discusses the expression of American identity in “Billy Rose’s Aquacade Show,” performed during the New York World’s Fair, 1939–1940. It seeks to contribute to a better understanding of the construction of identity by American public performance and costume around the start of World War II. The Aquacade used the American love of and pioneering role in sports by incorporating swimming, synchronized swimming, and diving. The kaleidoscopic patterns of the show, imitating a machine’s cogwheels, complemented the Fair’s theme of modernity and industrialization. The Aquacade’s swimwear combined innovative fabrics and glamorous, but practical, designs promoted by different West Coast swimwear companies. The American idolization of the physique, fashion, and lives of athletes was exemplified by the show’s employment of medalist swimmers. At a time when World War II threatened to cloud the future, Billy Rose cleverly encouraged sales by employing symbols of American identity.

Fabrication of seamless roller mould with smooth surface microstructures by rotation lithography and reflow process

In this work, the authors conducted a versatile approach for an innovative fabrication of a seamless micro-stripes array on the roller which is as a mould for roller imprinting lithography. The major steps in the proposed fabrication method include an uniform speed PR-coating process, followed by a digital micromirrors device based maskless lithography projection and an incremental step-and-rotate exposure process. In addition to above-mentioned steps, a following thermal reflow process was performed to transform the micro-stripes into smooth surface microstructures. The study also analysed the mechanism of the reflow process by numerical simulations and experiments. The mechanism includes the gravitational effect and the definition of the four stages of the reflow process. Study results show that the reflow process on the roller is feasible and the proposed method is a promising approach for fabricating three-dimensional smooth surface microstructures on the roller with different requirements.

Implantable Glass Waveguides and Coating Materials for Chronic Optical Medical Applications.

An innovative fabrication process of glass waveguides on silicon substrates for miniaturized implants is presented. Thin glass was bonded on oxidized silicon wafers and patterned using wet etching. Multimode waveguides with different shapes and a low surface roughness as well as low scattering of light were successfully fabricated. For efficient coupling of light and accurate alignment, KOH-grooves were etched in the silicon with respect to the glass waveguides to attach optical fibers from external light sources. Towards higher biostability, several coating materials were evaluated in accelerated in vitro tests in 60°C PBS for the first time over a long period of time regarding their optical properties. Ti02, SiC, polyimide, Parylene C and SU-8 showed a very stable optical transmittance after 320 days in accelerated aging while PECVDSi3N4 showed significant changes within the first days.

Utilisation of Himalayan Nettle plant waste for development of innovative union fabrics

Utilisation of Himalayan Nettle plant waste for development of innovative union fabrics

Interaction-tailored organization of large-area colloidal assemblies.

Colloidal lithography is an innovative fabrication technique employing spherical, nanoscale crystals as a lithographic mask for the low cost realization of nanoscale patterning. The features of the resulting nanostructures are related to the particle size, deposition conditions and interactions involved. In this work, we studied the absorption of polystyrene spheres onto a substrate and discuss the effect of particle–substrate and particle–particle interactions on their organization. Depending on the nature and the strength of the interactions acting in the colloidal film formation, two different strategies were developed in order to control the number of particles on the surface and the interparticle distance, namely changing the salt concentration and absorption time in the particle solution. These approaches enabled the realization of large area (≈cm2) patterning of nanoscale holes (nanoholes) and nanoscale disks (nanodisks) of different sizes and materials.

Cellulose Mineralization as a Route for Novel Functional Materials

AbstractCellulose possesses excellent properties, but its performance characteristics do not satisfy human requirements completely, which has soured a constant effort to improve its features. Currently, cellulose is combined with inorganics in a process called mineralization that results in a novel type of materials referred to as bio‐nanocomposites. There are many examples of mineralized tissues with superior properties in living nature. This circumstance gives us a reason to biomimic them by compounding biopolymers with inorganics. Here, the main mineralization techniques, properties, structure, functionality, and application of mineralized cellulose are the focus. Cellulose can be combined with inorganics through the vapor phase or by the methods of wet chemistry. Much attention has been paid to sol–gel chemistry, which is of first importance in cellulose mineralization. Inorganics can protect polysaccharides, regulate hydrophilicity–hydrophobicity, and impart self‐cleaning, antimicrobial and conducting properties, which not only improves them but results in bio‐nanocomposites with novel functionalities and performance, not known before for cellulosic materials. Further calcination and carbonization of mineralized cellulose under mild conditions give nanosized metals, metal oxides, and their nanocomposites with carbon, which are often unavailable by conventional methods. Therefore, mineralization is used to develop innovative textiles, oil absorbent and oil/water separating membranes, catalysts and photocatalysts, solar cells, conductors, supercapacitors, transistors and batteries for flexible electronics, and energy storage devices. These nontraditional and highly promising areas for applications have caused an intense interest in cellulose that resembles its rediscovery.

Recent progress on printable power supply devices and systems with nanomaterials

In recent years, tremendous research interest has been triggered in the fields of flexible, wearable and miniaturized power supply devices and self-powered energy sources, in which energy harvesting/conversion devices are integrated with energy storage devices into an infinitely self-powered energy system. As opposed to conventional fabrication methods, printing techniques hold promising potency for fabrication of power supply devices with practical scalability and versatility, especially for applications in wearable and portable electronics. To further enhance the performance of the as-fabricated devices, the utilization of nanomaterials is one of the promising strategies, owing to their unique properties. In this review, an overview on the progress of printable strategies to revolutionize the fabrication of power supply devices and integrated system with attractive form factors is provided. The advantages and limitations of the commonly adopted printing techniques for power supply device fabrication are first summarized. Thereafter, the research progress on novel developed printable energy harvesting and conversion devices, including solar cells, nanogenerators and biofuel cells, and the research advances on printable energy storage devices, namely, supercapacitors and rechargeable batteries, are presented, respectively. Although exciting advances on printable material modification, innovative fabrication methods and device performance improvement have been witnessed, there are still several challenges to be addressed to realize fully printable fabrication of integrated self-powered energy sources.

Anisotropic thermally conductive composite with wood-derived carbon scaffolds

In this study, we reported a thermally conductive composite with wood-derived 3D scaffold. The composites were easily fabricated by impregnating the polyamide-imide (PAI) into the wood scaffold and then in-situ carbonized. The well-aligned cellulose mircochannels in natural wood are maintained during the carbonization, leading to the improved anisotropic thermal conductive properties of the composite. The thermal conductivity of the composite reached 0.56 W·m−1·K−1 in cross-plane direction increasing by 250% and 0.22 W·m−1·K−1 in parallel direction, increasing by 37.5%, respectively. The unique structure of the composite also plays an important role in enhancing the mechanical performance. The Young’s modulus of the composite in vertical direction reached to 451.9 MPa, 4-times higher than that of natural wood in the same orientation. The integrated performance of the composites could be attributed to the alignment of cellulose nanofibers inherited from the natural wood. This study will provide an innovative design and fabrication of composite for thermal management.

Swimming Microrobots: Soft, Reconfigurable, and Smart

AbstractUsing materials with properties similar to those of cells and microorganisms together with innovative fabrication methods, soft and smart microrobots can be developed, with increased adaptability and flexibility toward in vivo applications. These tiny robots are designed to carry out difficult tasks such as noninvasive microsurgery, diagnosis and therapy in complex environments, including viscous media and intricate channels. Moreover, the novel property of the soft materials to respond to stimuli has paved the way for the creation of reconfigurable and smart microrobots with both actuation and function (e.g., sensing, drug delivery) capabilities. This feature article aims to give an overview of the different soft and smart swimming microrobots (less than 1 mm in all dimensions), highlighting some aspects of new materials, their development and the challenges in their processing to obtain highly functional microrobots.

Strategy of Action of Uzbekistan on the Development of Export of Textile Products

The article examines the theoretical and practical aspects of the Strategy of Uzbekistan’s actions in the development of the export of textile products. It analyzes: the export potential of the republic; strategies of «UZTEKSTILPROM» used for the development of the international textile market; modern directions of development of marketing strategies for the development of textile innovations, branding, fashion industry, product design, international quality standards, etc. are disclosed. Suggestions for further diversification of the sewing and knitting assortment of exported products and developing the textile market of the European Union and other countries are recommended.

Innovative textile technology with antimicrobial activity: preliminary tests

The prevalence of urinary tract infections (UTI) and antibiotic resistance prompts researchers to develop strategies for bacterial containment, such as antiseptic-active textiles. We verified the in vitro antimicrobial effect of innovative Nexus Energy Fiber compared to conventional cotton fabrics. The analytical procedure is performed in accordance with ASTM E-2180-07 document. Tests are realized both against clinical and reference UTI-responsible microorganisms by comparing CFUs declines on the two textiles, at different contact times (0, 6, 24, 48 hours) and at different distances between the fabrics and the microbial strains (0, 0.5-1 cm). Results show that Nexus Energy Fiber has a measurable bactericidal effect which depends on the distances and is directly proportional to the contact time on most of the tested microbial strains.

Synthesis and Characterization of Nanofunctionalized Gelatin Methacrylate Hydrogels.

Given the importance of the extracellular medium during tissue formation, it was wise to develop an artificial structure that mimics the extracellular matrix while having improved physico-chemical properties. That is why the choice was focused on gelatin methacryloyl (GelMA), an inexpensive biocompatible hydrogel. Physicochemical and mechanical properties were improved by the incorporation of nanoparticles developed from two innovative fabrication processes: High shear fluid and low frequencies/high frequencies ultrasounds. Both rapeseed nanoliposomes and nanodroplets were successfully incorporated in the GelMA networks during the photo polymerization process. The impact on polymer microstructure was investigated by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and enzymatic degradation investigations. Mechanical stability and viscoelastic tests were conducted to demonstrate the beneficial effect of the functionalization on GelMA hydrogels. Adding nanoparticles to GelMA improved the surface properties (porosity), tuned swelling, and degradability properties. In addition, we observed that nanoemulsion didn’t change significantly the mechanical properties to shear and compression solicitations, whereas nanoliposome addition decreased Young’s modulus under compression solicitations. Thus, these ways of functionalization allow controlling the design of the material by choosing the type of nanoparticle (nanoliposome or nanoemulsion) in function of the application.

Folded hybrid FRP-timber sections: concept, geometric design and experimental behaviour

Driven by an increasing demand for sustainable and easy-to-construct timber infrastructure, recent research at The University of Queensland (UQ) has led to the development of a new class of structures called ‘folded hybrid FRP-timber’ (FHFT) structures. In FHFT structures, FRP (fibre reinforced polymer) is combined with timber veneers to create high-performance, lightweight, easy-to-construct structural members. In such FHFT members, the fibre directions of FRP and timber are appropriately oriented to produce optimal composite properties, while the geometry of the cross section is designed to optimize the load bearing capacity for a given amount of material. This paper presents two highly innovative fabrication processes for FHFT sections that enable new geometric and material possibilities in the design of FHFT structural elements. The new fabrication processes are first demonstrated for the manufacture of regular structural hollow sections. A geometric design method is then presented for the fabrication of any folded structure with a uniform cross-section specified as a non-intersecting polygonal chain. An experimental study comparing the compressive capacity of FHFT and plywood-only columns is then presented. It is seen that the two fabrication methods produce FHFT hollow sections with similar capacities to each other and double the capacity relative to plywood-only sections. The new sections are also shown to have a weight-specific compressive strength comparable to that of existing commercial steel hollow sections.

Gold microelectrodes array embedded in PDMS for electrical stimulation and signal detection

In this paper, an innovative low cost fabrication process of a biocompatible MEA, composed of a group of gold microelectrodes embedded in a cavity filled with PDMS is presented. This MEA is part of a more complex system, which has been designed to stimulate, detect and amplify electrical signals. It is possible to control the temperature and heat the MEA, with the purpose of making this system suitable for biomedical application, such as cell or tissues culture, or monitoring neuronal activity. A deeply characterization of the MEA has been performed. The main experiment carried out consists in the introduction of an electrical signal through a gold microelectrode. This electrical signal is transmitted between microelectrodes through a water-based salt solution, in particular with Phosphate Buffered Saline (PBS). In order to have the possibility of amplifying a wide range of signals, different INA 333 amplifiers with different gains, between 3.13 and 213, have been included. Nevertheless, the gain could be easily modified. The behavior of the system is controlled via Labview software, provided by National Instruments. This program allows for detecting the stimulus, the stimulation and an accurate measurement of the temperature's system. An electronic circuit, which includes the conditioning circuits needed to run the whole system, is used as an interface between the MEA and the Labview software. The proper functioning of the system introduced, and the stimulation and detection of electrical signals, as well as its amplification through a water-based salt solution, using gold microelectrodes embedded in PDMS, have been demonstrated. A survival test with mice retinas has been performed to demonstrate the biocompatibility of the MEA.

Bioinspired Surfaces with Superwettability for Anti-Icing and Ice-Phobic Application: Concept, Mechanism, and Design.

Ice accumulation poses a series of severe issues in daily life. Inspired by the nature, superwettability surfaces have attracted great interests from fundamental research to anti-icing and ice-phobic applications. Here, recently published literature about the mechanism of ice prevention is reviewed, with a focus on the anti-icing and ice-phobic mechanisms, encompassing the behavior of condensate microdrops on the surface, wetting, ice nucleation, and freezing. Then, a detailed account of the innovative fabrication and fundamental research of anti-icing materials with special wettability is summarized with a focus on recent progresses including low-surface energy coatings and liquid-infused layered coatings. Finally, special attention is paid to a discussion about advantages and disadvantages of the technologies, as well as factors that affect the anti-icing and ice-phobic efficiency. Outlooks and the challenges for future development of the anti-icing and ice-phobic technology are presented and discussed.

Benign development of cotton with antibacterial activity and metal sorpability through introduction amino triazole moieties and AgNPs in cotton structure pre-treated with periodate

The research work presented herein was undertaken with a view to develop, characterize and highlight modified cotton fabrics that acquire durable antibacterial activity in concomitant with high metal sorption capacity. The development is based on reacting cotton cellulose previously oxidized by sodium periodate-with 4 amino-1,2,4 triazole in presence and absence of silver nano particles (AgNPs). The idea behind the periodate pretreatment is to convert (via oxidative cleavge) the 2,3-vicinal diol of the anhydroglucose units of cotton into aldehyde groups. The latter are easily reacting with the triazole groups in the modified cotton. On the other hand AgNPs were fabricated as per the reduction method using bio-material extracted from the root of licorice. By virtue of its reducing action, the bio-material converts Ag+ ions to Ag0 atom which is also stabilized Ag the bio-material in the form of cluster which is the agregate of about 5 Ag0. The clusters are cropped with the stabilizer thus forming silver nanoparticles.Measurement of the particle size displays a value of 8.7nm. Charactrisation of triazole treated cotton fabrics reveals the presence of the triazole moieties inside the structure of cotton. Furthermore, Fabrictreated with triazole in presence and absence of AgNPs exhibits a relatively high antibacterial activity against gram-negative tested bacteria (E. coli) as compared to that of gram-positive tested bacteria (S. aureus). The metal sorption of triazole treated cotton fabrics was higher than those of untreated or periodate pretreated fabric due to the increase in nitrogen centers created along the cellulose chains. Experimental data were accomplished through Langmuir, Freundlich and Temkin sorption isotherm models. It was shown that sorption follows Langmuir isotherm model and suggests that the innovative fabric in question can adsorb metal ions from polluted dye bath.

Improving the mechanical properties of carbon nanotube-reinforced pure copper matrix composites by spark plasma sintering and hot rolling

The poor dispersion of carbon nanotubes (CNTs) in a copper matrix and the weak interfacial bonding between CNTs and the Cu matrix critically hinders the engineering applications of their composites. Herein, we obtained a well-dispersed and tight interfacial bonding between CNTs and Cu matrix in the Cu/CNTs composites fabricated via spark plasma sintering and subsequently hot rolling. Microstructural characterization shows that the small grain size of Cu matrix, the uniform dispersion of CNTs, and the good wettability and interfacial bonding between the CNTs and Cu significantly improved the mechanical properties of the Cu/CNTs composite. This work provides an innovative fabrication process for the development of high performance Cu/CNTs composites with excellent interfacial bonding strength.

3D Printed Hybrid Electrodes for Lithium-Ion Batteries

A novel hybrid 3D structured electrode, with a high-aspect ratio, is fabricated via extrusion-based additive manufacturing to achieve high mass loading and combine the advantages offered by a conventional laminated structure and a 3D digital structure. This structure is designed to enhance interfacial reactions and species transport by utilizing the 3D structure. Two key challenges in 3D structured electrodes are addressed, including solution preparation and scale-up. The paste is optimized with a high viscosity to avoid the typical complexity encountered in preparing a solution for 3D printing, and the proposed hybrid 3D structures can be easily added to the conventional laminated structures. This is demonstrated by using a CR2032 coin cell, which also solves the typical assembly problems that occur with 3D structured electrodes. This innovative design and fabrication process demonstrates high areal energy and power density, which are critical requirements for energy storage systems in transportation and stationary applications.