Fabrication Of Patterns Research Articles

Sustainable Fabrication and Transfer of High-Precision Nanoparticle Arrays Using Recyclable Chemical Pattern Templates.

Nanoparticle (NP) arrays, particularly those with plasmonic properties, have diverse applications in electronics, photonics, catalysis, and biosensing, but their precise and scalable fabrication remains challenging. In this work, a facile chemical-based strategy is presented for the fabrication of precise NP patterns using a combination of soft thermal nanoimprinting and template-directed assembly. The approach enables the creation of well-defined NP arrays with single-particle resolution and yields over 99%, covering a diverse range of NP sizes from 30 to 150nm. These patterns can be transferred onto various substrates including semiconductors, insulators, 2D materials, and flexible polymers, maintaining high uniformity and repeatability for over 60 cycles with minimal degradation. Moreover, the method enables the fabrication of extensive NP arrays up to 1 cm2 with a positional accuracy of ±11 nm for 30nm NPs. As a result, the obtained silver NP arrays exhibit ultranarrow surface lattice resonances with a linewidth of 4nm and a quality factor (Q) of 216. The method offers new avenues for the creation of plasmonic NP arrays for flexible and wearable devices.

Yarn‐to‐Yarn Surface Area and Roughness as Structural Engineering Tools for Optimizing the Electrical Output of Triboelectric Nanogenerators: Geometrical and Experimental Verification

AbstractThis paper investigates the performance of woven triboelectric nanogenerators (W‐TENGs) fabricated with different fabric patterns, specifically plain, twill, and hopsack weaves, using wool and polyester yarns. It is intended to enhance the electrical output and efficiency of W‐TENGs for potential applications in wearable electronics by optimizing the weaving pattern. Results indicate that W‐TENGs with twill 2/2 and hopsack 2/2 patterns exhibit superior electrical outputs, attributed to their higher contact surface area and roughness. The twill 2/2 pattern demonstrates the highest electrical output, generating an open‐circuit voltage of 4.7 V, a short‐circuit current of 4 µA, and a transferred charge of 0.35 µC. This study also highlights the critical role of surface area and dielectric material roughness in determining the output performance of triboelectric structures. A theoretical model is developed to calculate the real contact surface area of the woven fabrics with different patterns. Statistical analysis reveals significant relationships between surface roughness parameters and electrical performance. Dynamic testing under varying contact forces and frequencies demonstrates the practical applicability and robustness of the W‐TENGs. Furthermore, the devices exhibit excellent durability, maintaining stable performance over extended periods. This research provides new insights into fabric design strategies for optimizing energy harvesting in wearable devices.

Development platform for UV-NIL processes using polymer masters produced by laser ablation and photolithography

Ultraviolet nanoimprint lithography (UV-NIL) is a versatile and cost-effective technique for the fabrication of micro- and nanostructures by copying master patterns in a planar or a roll-to-roll process through curing of a liquid UV-sensitive precursor. For applications with a high pattern complexity, new UV-NIL process chains must be specified. Master fabrication is a challenging part of the development and often cannot be accomplished using a single master fabrication technique. Therefore, an approach combining different patterning fabrication techniques is developed here for polymer masters using laser direct writing and photolithography. The polymer masters produced in this way are molded into inverse silicone stamps that are used for roll-to-roll replication into an acrylate formulation. To fit the required roller size for large-area UV-NIL, several submasters with micrometer-sized dot and line gratings and prism arrays, which have been patterned by these different techniques, are assembled to final size of ∼200 × 600 mm2 with an absolute precision of better than 50 µm. The size of the submasters allows the use of standard laboratory equipment for patterning and direct writing, thus enabling the fabrication of micro- and even nanostructures when electron-beam writing is utilized. In this way, the effort, time, and costs for the fabrication of masters for UV-NIL processes are reduced, enabling further development for particular structures and applications. Using this approach, patterns fabricated with different laboratory tools are finally replicated by UV-NIL in an acrylate formulation, demonstrating the high quality of the whole process chain.

Water-Vapor-Triggered Dual-Mode Optical Responses in Rare-Earth-Doped Hollow Nanospheres.

Multimode responsive optical materials are garnering ever-increasing attention due to their diverse applications. This work showcases a film assembled with rare-earth-doped CaF2 hollow nanospheres that exhibit water-vapor-triggered dual-mode optical responses. Upon exposure to flowing water vapor, the film rapidly (less than 1.5 s for a 7.7 μm thickness) transitions to a transparent state and simultaneously undergoes a sharp decrease in the photoluminescence intensity. Both of these changes fully reverse upon water evaporation, demonstrating an impressive reversibility over at least 200 cycles. The water-vapor-induced dual-mode responses are attributed to the altered incident light propagation path stemming from the similar refractive indices between CaF2 and water, coupled with the water-induced energy loss of the rare-earth ions. The fabrication of encryption patterns displaying separate signals in multiple channels, as well as the demonstration of noncontact sensing for water vapor distribution, underscore the promising application potential of this dual-mode responsive system.

Synthesis and application of lead iodine-based perovskite nanomaterials

In this study, we employed a modified ligand-assisted recrystallization precipitation (LARP) method to synthesize perovskite nanomaterials with emission peaks ranging from 515 nm to 683 nm. The synthesis of these nanomaterials with different emission peaks was achieved by simply controlling the type and amount of cesium oleate. These CsPbI3 nanomaterials possess different morphologies, and all of them show excellent PL properties. Furthermore, by simply mixing the nanomaterials with sodium citrate, a large quantity of powders of various colors was obtained, which can be used for the fabrication of multicolor patterns.

A multifunctional and tough lotus root starch-based bio-photonic hydrogel for stretchable fabric pattern color change and water rewriting.

Photonic crystal hydrogels (PCHs) are innovative materials that translate imperceptible deformations and humidity changes into visible colors, broadening the applications of photonics in bioengineering and smart materials. To overcome poor mechanical properties of traditional PCHs limited by weak intermolecular forces, we designed a PCH with a dual-network framework comprising N-isopropylacrylamide-co-acrylamide (NIPAM-co-AM) and biomass lotus root starch (LR). Since LR is rich in hydroxyl groups, it can undergo molecular linkage entanglement with the NIPAM-co-AM hydrogel matrix, forming hydrogen bonds that significantly enhance the mechanical properties of the PCH. We have prepared PCH films capable of conveying multidimensional information about the extent and distribution of transient deformation by encapsulating magnetic photonic crystal microspheres (MPCMs) within a hydrogel matrix. The PCH films were found to have ultrafast response time (< 10 s), full-color tunable range, high spatial resolution, excellent mechanical toughness (tensile up to 0.17 MPa) and sensitivity (2.52 nm %-1), and were able to sense relative humidity (RH) from 11 % to 98 %. Equipped with a dynamically reconfigurable lattice, this dual-responsive (tensile/humidity) PCH not only facilitates the creation of water-rewritable photonic films but also holds promise for integration into structural color elastic fabrics, thereby presenting novel prospects for smart textile applications.

Visual pattern auto-generation for yarn-dyed plaid fabric based on modified genetic operators

With the aggravated homogenization of the commodity in the increasingly competitive marketplace, the industries have been converted to design and manufacture small batch productions with a wide variety. To reduce the designer’s burden and shorten the design cycle of the product, an auto-generation method for the pattern of yarn-dyed fabric was proposed based on the modified genetic operators. Initially, the design elements to form the pattern were extracted and encoded as a chromosome by natural number encoding. Then, the fabric weave model was built using the matrix of 0 and 1. Based on the color scheme and yarn arrangement, the pattern of yarn-dyed fabric can be generated automatically. The elements can be exchanged to generate new patterns by the genetic operators. Finally, the obtained pattern was imported into the three-dimensional virtual shirt model. Experiments show that the proposed method can help the designer obtain different patterns quickly and effectively, and different design elements can be controlled according to the requirements of the designer. Based on the annual fashion trend, fashionable colors can be involved to realize fast reaction in product design.

Surface modification and patterning of polymer thin films by plasma and adsorption behavior of proteins

The surface wettability property of hydrophobic polystyrene (PS) and hydrophilic polyethylene glycol (PEG) thin films subjected to modification by direct current plasma glow discharge is studied. The polymer films exhibited change of surface wettability on exposure to air, nitrogen, oxygen or argon plasmas. In PS films a swift modification to hydrophilic surface and subsequent steady recovery following first order kinetics are observed. The rate of modification and recovery are adjustable by adjusting the plasma ambient and parameters, and additional wet-chemical treatment using ionic solutions. In PEG films the hydrophobic wettability evolve with ageing following the first order kinetics, and is stable for long period on exposure to air ambient. Moreover, a vapor deposition like process is possible using the PEG films as source to deposit self-assembled molecular layers with hydrophobic wettability on other surfaces. Using surface modification or molecular deposition processes, the fabrication of wettability patterns in the surface of PS and PEG films, and on other surfaces by vapor transport using PEG films, and also the possibility to produce gradient wettability patterns are demonstrated. Moreover, the adsorption behavior of immuno-specific system of proteins on surface modified hydrophilic PS films is studied.

Effect of structural parameters on formability of auxetic weft-knitted fabrics based on zigzag structure

Auxetic materials are characterized by a negative Poisson’s ratio (NPR), which expands when stretched and shrinks when compressed. Due to the synclastic curvature of auxetics, they have good formability. These properties make them useful in applications requiring formability, such as composites, fashion and clothing, medical, protective, and sports fields. In this research, auxetic weft-knitted fabrics based on foldable structures were knitted. The effect of structural parameters including fabric pattern, yarn count, and loop length on the formability of auxetic weft-knitted fabrics was investigated and compared to plain weft-knitted fabric (Jersey). Auxetic fabrics with three distinct patterns and three different loop lengths were knitted using polyester yarns of varying three counts. Then, the formability experiment was conducted using the hemisphere mold, and the forming energy of fabric samples was obtained. The results demonstrated that auxetic fabrics exhibit superior formability to conventional (non-auxetic) fabrics, attributed to their synclastic curvature. Among the auxetic fabrics, those with larger zigzag angles, finer yarn counts, and larger loop lengths showed higher formability. These findings enhance the potential applications of auxetic fabrics in various industries such as medical and protective, emphasizing their ability to conform to complex shapes with minimal wrinkling.

Influence of Prosopis juliflora bark powder/fillers on the mechanical, thermal and damping properties of jute fabric hybrid composites

In recent years, the natural fiber (NF) reinforced composites have become popular as substitute material for conventional metals and alloys in a range of structural applications. The aim of this experiment is to utilize the waste of both Prosopis Juliflora (PJ) bark and Jute fabric in valuable applications for the first time. The influence of fabric stacking patterns on the mechanical characteristics (ductile, flexural, hardness and impact) and thermal stability of fabric Jute/PJ bark powder reinforced hybrid composites in the epoxy matrix is investigated in this task. The compression moulding method is used to create composite laminates of same widths that are layered in various combinations of 5%, 10% and 15% weight of PJ bark powder. The prepared reinforced test samples characteristics of tensile, flexural, impact, and hardness characteristics are experimentally investigated. The outcomes revealed an inclusion of 15 wt% of PJ bark powder reveals positive effect on tensile, flexural, impact, hardness and thermal characteristics. These composites have a diverse range of applications, including industries, automobile and civil applications.

Fabrication of GelMA - Agarose Based 3D Bioprinted Photocurable Hydrogel with In Vitro Cytocompatibility and Cells Mirroring Natural Keratocytes for Corneal Stromal Regeneration.

The complex anatomy of the cornea and the subsequent keratocyte-fibroblast transition have always made corneal stromal regeneration difficult. Recently, 3D printing has received considerable attentionin terms of fabrication of scaffoldswith precise dimension and pattern. In the current work, 3D printable polymer hydrogels made of GelMA/agarose are formulated and its rheological properties are evaluated. Despite the variation in agarose content, both the hydrogels exhibited G'>G'' modulus. A prototype for 3D stromal model is created using Solid Works software, mimicking the anatomy of an adult cornea. The fabrication of 3D-printed hydrogels is performed using pneumatic extrusion. The FTIR analysis speculated that the hydrogel is well crosslinked and established strong hydrogen bonding with each other, thus contributing to improved thermal and structural stability. The MTT analysis revealed a higher rate of cell proliferation on the hydrogels. The optical analysis carried out on the 14th day of incubation revealed that the hydrogels exhibit transparency matching with natural corneal stromal tissue. Specific protein marker expression confirmed the keratocyte phenotype and showed that the cells do not undergo terminal differentiation into stromal fibroblasts. The findings of this work point to the potential of GelMA/A hydrogels as a novel biomaterial for corneal stromal tissue engineering.

E-beam Lithography Technology for Quantum Device Fabrication and Nanoscale Patterning

Currently nanotechnology becoming more important with the implementation of nano devices including quantum devices. In this paper, we will briefly introduce the JEOL JBX-8100FS e-beam lithography tool which was recently installed in Hallym University and the current status of the exposure conditions set up. As applications using e-beam lithography tool, we will introduce Schottky barrier single hole transistor and silicon nanowire thermoelectric device, respectively. We are under researching plasmonic and quantum devices as basic research.

PERANCANGAN BUSANA SIAP PAKAI DENGAN MATERIAL UTAMA TENUN SUMBA LAU PAHIKUNG BERDASARKAN ANALISIS KEBUTUHAN PASAR URBAN

Indonesia's diverse handicrafts include Lau Pahikung woven cloth from Sumba Island, East Nusa Tenggara. Lau means sarong in the local language, and Pahikung is a weaving technique for fabric patterns. This cloth, made using ikat and Pahikung dyeing, is crafted into sarongs for Sumba women. The research partners with the Sekar Kawung Foundation, supported by weavers in East Sumba, who use sustainable methods to create Lau Pahikung fabrics. These fabrics are transformed into urban product displays through market analysis. The analysis, incorporating Maslow's needs theory and Indonesia Trend Forecasting, leads to ready-to-wear fashion designs that cater to specific formal clothing needs, offering versatile contemporary styles.

Fabric Defect Detection Using Transfer Learning

Transfer learning in fabric defect detection involves utilizing pre-trained deep learning models on a large dataset, typically from a different domain, and fine-tuning them on a smaller dataset that is specific to fabric defects. By leveraging transfer learning, the limitations of limited annotated data for fabric defect detection can be overcome by utilizing the knowledge gained from a more extensive and diverse dataset. The pre-trained model's learned features are adjusted to recognize specific fabric defect patterns, resulting in more accurate and efficient defect detection. This approach reduces the reliance on a massive labelled dataset for training, which is particularly beneficial in industrial applications where obtaining a vast amount of annotated fabric defect images may be challenging. Ultimately, transfer learning enhances the model's ability to generalize and detect fabric defects with higher precision, thereby contributing to improved quality control in textile manufacturing processes.

Confined Flash Printing and Synthesis of Stable Perovskite Nanofilms under Ambient Conditions.

The fabrication of stable perovskite nanofilm patterns is important for the development of functional optical devices. However, current production approaches are limited by the requirement for strict inert gas protection and long processing times. Here, a confined flash printing synthesis method is presented to generate perovskite nanofilms under ambient conditions, combining precursor transfer, perovskite synthesis, crystallization, and polymer protection in a single step within milliseconds. A laser simultaneously prints and induces the flash synthesis, confined in a polymer nanofilm, under normal ambient conditions. Due to its simplicity and flexibility, the method enables the combination and screening of many different perovskite precursor materials on various substrates. Besides for the development of novel perovskite materials and devices, the nanofilms can be applied for biodetection. The unique H2O2-responsive property of the ultrathin perovskite quantum dot film is applied for biomolecule detection based on oxidase-catalyzed enzymatic reactions.

Repositioning of an Engineering Works Complex as an Industrial Hub for Spare Parts and Components Production

Ajaokuta Steel Company Limited (ASCL) comprises several units, including the Engineering Works Complex, which is one of the key auxiliary units of the steel plant. This complex is equipped with the necessary tools and machinery for producing fixtures and spare parts that meet a wide range of requirements. These machines are operated by welltrained engineers, skilled technicians, and artisans. The complex is designed to carry out repairs on equipment across the entire steel plant, as well as to manufacture spare parts for external agencies. Additionally, facilities are available for training technicians and artisans. The Engineering Works Complex consists of five major workshops: the Machine and Tools Shop, Forge and Fabrication Shops, Foundry and Pattern Making Shops, Power Equipment and Repair Shops, and the Rubberizing Shop. It is fully equipped to meet the industrial demand for spares and consumables, and it has the capacity to serve as a research institution where modern research can be conducted. This research aims to explore the potential of repositioning the Engineering Works Complex at Ajaokuta Steel Company as a leading industrial hub for the production of spare parts and components in Nigeria. The study will analyze the potential economic benefits of this repositioning, such as increased employment opportunities, higher productivity, and greater contributions to the national economy. By drawing on case studies from other countries that have successfully developed their engineering sectors, the research will provide insights and lessons that can be applied to the Nigerian context. The Engineering Works Complex is actively utilizing the government's local content policy to achieve these goals. With the necessary attention, including adequate funding for the various shops within the complex, it could generate significant revenue and create employment opportunities in downstream industries, ultimately contributing to the industrialization of local communities and the country at large.

Geometrical incompatibility regulated pattern selection and morphological evolution in growing spherical soft tissues

Surface morphological patterns are widely observed in natural systems, which are closely correlated to vital biological functions and inspire surface morphology designs in soft matter systems. Geometrical incompatibility widely exists in biological tissues across different length scales and plays an important role in growth-induced pattern selection and morphological evolution of soft tissues. However, the underlying physical mechanism of growth-induced pattern formation and post-buckling evolution in geometrically incompatible spherical soft tissues remain elusive. Here, the effect of geometrical incompatibility on the growth-induced pattern selection and post-buckling evolution are investigated through swelling experiment, theoretical analysis and numerical simulation. The results show that not only the instability pattern but also the instability threshold can be regulated by manipulating geometric incompatibility. Notably, when the geometrical incompatibility parameter exceeds a critical value, spontaneous instability is observed before growth. With continuous growth, the core–shell soft sphere buckles into a periodic buckyball pattern and evolves toward a bean-shaped pattern, and then undergoes a wrinkle-to-fold transition into a labyrinth topography. Our results demonstrate, both experimentally and theoretically, that geometrical incompatibility can guide the growth-induced pattern formation and morphological evolution effectively. This study not only enhances our understanding of the growth-induced pattern selection and morphological evolution in spherical soft tissues, but also provides an inspiring insight for the fabrication of morphological patterns on curved surfaces.

Large‐Area Photomodification of Nanotopography for Controlling Cell Behavior

AbstractNanotopographic surfaces are a powerful tool for studying and controlling cell behavior. However, the fabrication of nanotopographic master patterns using conventional photolithography is expensive, which limits the range of designs that can be explored. In this study, a method is demonstrated for the photoreshaping of large‐area patterns of nanoridges. The original master pattern is created using conventional lithography, and an azopolymer replica is prepared using soft lithography. The manipulation of the nanoridges is achieved by projecting light with specific polarizations and exposure times, resulting in controllable widening, buckling, or removal of the ridges. The reprogrammed azopolymer master patterns can then be replicated, creating reproducible new nanotopographies that can be transferred into other materials using a molding procedure. Diffraction can be used for in situ monitoring of the reprogramming during exposure. Image‐analysis methods are used to characterize buckled ridges as a function of exposure time. The response of MCF10A epithelial cells are investigated to buckled nanoridges. A substantial impact of buckling on the dynamics and location of actin polymerization, as well as on the distribution and lengths of contiguous polymerized regions is also observed.

The effect of pattern fabrication methods on the marginal fit of three‐unit implant‐supported frameworks: An experimental study

AbstractObjectiveThis in vitro study aimed to evaluate and compare the marginal fit of three‐unit implant‐supported frameworks fabricated based on conventionally hand‐waxed, milled, and three‐dimensional (3D) printed patterns.Materials and MethodsTwo fixture analogs were placed in the mandibular right first premolar and first molar region of the dentiform and two prefabricated abutments were secured in the fixture analogs. Thirty three‐unit wax patterns were fabricated through conventional, milling, and 3D printing techniques (n = 10 per group). After casting, the vertical marginal gaps of two abutments for each restoration were measured by using an optical microscope on 16 points around the finish line at ×80 magnification. The data were analysed by using one‐way ANOVA and Tukey's post hoc test (α = 0.05).ResultsThe marginal gap was found to be significantly different among the three manufacturing methods (p &lt; 0.001) and between each pair (p &lt; 0.001). The 3D printing group had a significantly lower marginal gap than the milling (p &lt; 0.001) and the conventional group (p &lt; 0.001) in the first premolar and first molar regions and the mean of the two. The marginal gap in the milling group was significantly lower than that of the conventional group (p &lt; 0.001) in the first premolar and first molar regions and the mean of the two.ConclusionThe marginal fit of the frameworks was the best in the 3D printing method, followed by the milling, and finally the conventional method. However, the fit accuracy in all three methods remained within the clinically acceptable range (&lt;120 μm).

Analysis of pool boiling heat transfer characteristics on copper-based structured surfaces modified with superhydrophilic, hydrophobic, superhydrophobic and hybrid biphilic properties

This study involves the fabrication and characterization of original, hydrophobic, superhydrophilic, superhydrophobic and hybrid biphilic pattern coupled with the flat and pillar-structured surfaces. The boiling performance of the seven wettability structured surfaces is experimentally and numerically investigated, aiming at analyzing the boiling mechanism of wetting pattern coupled with structures. The findings indicate that coupling superhydrophobicity pillar structure surface (SHO-PS) result in an excellent boiling performance, the superhydrophilicity have difficulty in improving the heat transfer coefficient and critical heat flux. Analysis of the bubble dynamics behaviors reveals a strong positive correlation between the bubble nucleation sites and bubble departure diameter, except for hydrophobic flat structured surface (HO-FS) and superhydrophobicity pillar structured surface (SHO-PS), which exhibit the negative correlation. The bubble departure frequency shows a linear correlation with the contact angle of all the modified surfaces. In the simulation, it is observed that the similar bubble dynamic behaviors in experiment.