Rapid Tissue Perfusion Using Sacrificial Percolation of Anisotropic Networks.

Tissue engineering has long sought to rapidly generate perfusable vascularized tissues with vessel sizes spanning those seen in humans. Current techniques such as biological 3D printing (top-down) and cellular self-assembly (bottom-up) are resource intensive and have not overcome the inherent tradeoff between vessel resolution and assembly time, limiting their utility and scalability for engineering tissues. We present a flexible and scalable technique termed SPAN - Sacrificial Percolation of Anisotropic Networks, where a network of perfusable channels is created throughout a tissue in minutes, irrespective of its size. Conduits with length scales spanning arterioles to capillaries are generated using pipettable alginate fibers that interconnect above a percolation density threshold and are then degraded within constructs of arbitrary size and shape. SPAN is readily used within common tissue engineering processes, can be used to generate endothelial cell-lined vasculature in a multi-cell type construct, and paves the way for rapid assembly of perfusable tissues.

Comparative Study of Polymer-Modified Copper Oxide Electrochemical Sensors: Stability and Performance Analysis.

The effectiveness of copper oxide-modified electrochemical sensors using different polymers is being studied. The commercial powder was sonicated in an isopropyl alcohol solution and distilled water with 5 wt% polymers (chitosan, Nafion, PVP, HPC, α-terpineol). It was observed that the chitosan and Nafion caused degradation of CuO, but Nafion formed a stable mixture when diluted. The modified electrodes were drop-casted and analyzed using cyclic voltammetry in 0.1 M KCl + 3 mM [Fe(CN)6]3-/4- solution to determine the electrochemically active surface area (EASA). The results showed that α-terpineol formed agglomerates, while HPC created uneven distributions, resulting in poor stability. On the other hand, Nafion and PVP formed homogeneous layers, with PVP showing the highest EASA of 0.317 cm2. In phosphate-buffered saline (PBS), HPC and PVP demonstrated stable signals. Nafion remained the most stable in various electrolytes, making it suitable for sensing applications. Testing in 0.1 M NaOH revealed HPC instability, partial dissolution of PVP, and Cu ion reduction. The type of polymer used significantly impacts the performance of CuO sensors. Nafion and PVP show the most promise due to their stability and effective dispersion of CuO. Further optimization of polymer-CuO combinations is necessary for enhanced sensor functionality.

Fabrication of high performance poly(vinyl alcohol)/straw composite film used for package via melt casting and biaxial stretching.

A high performance poly(vinyl alcohol)/straw (PVA/SP) composite film for package was fabricated in this study by using thermal processing technology of PVA established in our research group and biaxial stretching technology. The introduction of SP disrupted the original hydrogen bonds in modified PVA by forming new hydrogen bonds with the hydroxyl groups of each component in modified system, thus promoting the stable melt casting of PVA/SP composites and also endowing the obtained PVA/SP precursor sheets with good drawability. Upon biaxial stretching, SP reinforced the crystalline structure and orientation of PVA through their hydrogen bonds with PVA, improving the mechanical strength, crystallinity and thermal stability of PVA/SP films. The film with 3.0 × 3.0 stretching ratios demonstrated the exceptional tensile strength (62.2 MPa), tear strength (119.7 kN/m), low heat shrinkage (5.2 %), and oxygen permeability coefficient (1.38 × 10-16 cm3·cm/cm2·s·Pa), which surpassed most conventional plastic films used in food packaging field. This research not only pioneered an environmentally friendly packaging solution, but also offered a novel strategy for solid-state high-value, large-scale and economical utilization of waste crop straw, greatly avoiding the adverse effects of its burning on the environment.

Analysis and optimization of machining parameters of AZ91 alloy nanocomposite with the Influences of nano ZrO2 through vacuum diecast process.

The magnesium alloy composite is a vital material for automotive applications due to its features like high stiffness, superior damping resistance, high strength, and lightweight. Here, the motto of research is to establish the AZ91 alloy nanocomposite with the exposures of 0, 1, 3, and 5 volume percentages (vol%) of nano zirconium dioxide (ZrO2) particles (50nm) through fluid stir metallurgy route associated with 1x105 Pa vacuum die cast process. Exposures on structural morphology, hardness, and impact toughness of composite are analyzed and identified as the nano AZ91 alloy composite enclosed with 5vol% is homogenous particle dispersion, enhanced hardness (97.6HV), and optimum toughness of 21.2J/mm2. However, composite faces machining difficulties due to the hard abrasive particles with higher hardness, resulting in tool wear. This experiment predicts the optimum mill parameters during the end mill operation of magnesium alloy nanocomposite (AZ91/5vol%) by using a tungsten carbide coated end mill cutter to attain the maximum metal removal rate with low surface roughness and tool wear analyzed via the general linear model (GLM) ANOVA approach. The input conditions for end milling operation vary, like feed rate (0.1 -0.4mm/rev), depth of cut (0.05 -0.2mm), and spindle speed (250-1000rpm). During the ANOVA GLM approach, the L16 design experiment is fixed for further interaction analysis. The results predicted by the depth to cut and feed rate were dominant and played a major role in deciding the tool wear, surface roughness, and MRR.

The Efficacy of Thumb Spica Casting With or Without Corticosteroid Injection for De Quervain's Tenosynovitis.

Background and objective De Quervain's tenosynovitis is a highly prevalent wrist pathology primarily caused by chronic thumb overuse. Its management typically begins with conservative methods, progressing to corticosteroid injections or surgery if necessary. This study compares the efficacy of thumb spica casting plus corticosteroid injection versus casting alone for treating De Quervain's tenosynovitis. Materials and methods This quasi-experimental study was conducted at the Department of Orthopaedics, Khyber Teaching Hospital, Peshawar, and enrolled adults aged 18-50 who presented with De Quervain's tenosynovitis. Patients were assigned to receive either corticosteroid injection plus thumb spica cast (Group A) or thumb spica cast alone (Group B). The primary outcome assessed the treatment success rate, while the secondary outcome evaluated the treatment effectiveness using visual analog scale (VAS) scores and Quick Disabilities of Arm, Shoulder, and Hand (QuickDASH). Results Of the initial 65 patients enrolled, 61 completed the study. Group A demonstrated a significantly higher treatment success rate (83.9%, n=26) compared to Group B (40%, n=12) (p<0.001). Pain reduction, as measured by VAS, was markedly greater in Group A (8.4 ± 1.0 to 0.4 ± 0.5) than in Group B (9.0 ± 0.8 to 5.9 ± 1.3) (p<0.001). Similarly, functional improvement assessed by QuickDASH favored Group A (89.6 ± 8.2 to 8.9 ± 6.8) over Group B (84.3 ± 10.1 to 49.1 ± 12.3) (p<0.001). No serious adverse effects related to treatments were noted in either of the groups. Conclusions This study supports the superiority of thumb spica casting along with local corticosteroid injection over casting alone for treating De Quervain's tenosynovitis. The combined approach led to significantly better pain relief and functional outcomes, highlighting its effectiveness as a treatment option despite the positive outcomes observed with casting alone.

A novel macroporous carboxymethyl chitosan/sodium alginate sponge dressing capable of rapid hemostasis and drug delivery.

Carboxymethyl chitosan (CMCS) and sodium alginate (SA), which are excellent polysaccharide-based hemostatic agents, are capable of forming polyelectrolyte complexes (PEC) through electrostatic interactions. However, CMCS/SA PEC sponges prepared by the conventional sol-gel process exhibited slow liquid absorption rate and poor mechanical properties post-swelling. In this work, a novel strategy involving freeze casting followed by acetic acid vapor treatment to induce electrostatic interactions was developed to fabricate novel PEC sponges with varying CMCS/SA mass ratios. Compared to sol-gel process sponges, the novel sponges exhibited a higher density of electrostatic interactions, resulting in denser pore walls that resist re-gelation and swelling according to FTIR, XRD, and SEM analyses. Additionally, the liquid absorption kinetics, as well as compression and tension tests, demonstrated that the novel sponges had significantly improved rapid blood absorption capacity and mechanical properties. Furthermore, in vitro coagulation and drug release studies showed that the novel sponge had a lower blood clotting index and clotting time, along with a slower drug release rate after loading with berberine hydrochloride, showcasing its potential as a rapid hemostatic dressing with controlled drug release capabilities.

Analysis of the Effect of Layer Height on the Interlayer Bond in Self-Compacting Concrete Mix in Slab Elements.

This paper presents a study on the influence of the layered casting technology of self-compacting concrete (SCC) on the load-bearing capacity of interlayer bond in slab elements. The research was conducted on slab elements with dimensions of 750 × 750 × 150 mm, concreted from a single point of concrete delivery. The aim of this study was to analyse the influence of the height of the concreting top layer on the bond strength between the layers. The study utilised top layer heights of 50, 75, and 100 mm, which, according to the authors' experience, are the most common cases when making slab elements. The interlayer bond was determined by investigating the splitting tensile strength of cubic specimens cut from the concrete slabs. Computed tomography (CT) was employed to image the contact zone between the concrete layers. Based on the analysis of the CT imaging and the results of the strength tests, it was shown that the interlayer bond is influenced by both the height of the top layer and its free-spread distance from the casting point. A reduction in the interlayer bond strength was observed with decreasing the height of the top layer and increasing distance from the mixture supply point. The relationships obtained were linear and had a clearly negative slope. It was concluded that the valid recommendations and standards for the multilayer casting of SCC are too general. Therefore, we propose to detail the recommendations to reduce the risk of cold joints, which diminish the bond strength of the interlayer joints.

Development of Low-Pressure Die-Cast Al-Zn-Mg-Cu Alloy Propellers Part II: Simulations for Process Optimization.

With the increasing demand for high-performance leisure boat propellers, this study explores the development of high-strength aluminum alloy propellers using the low-pressure die-casting (LPDC) process. In Part I of the study, we identified the optimal alloy compositions for Al-6Zn-2Mg-1.5Cu propellers and highlighted the challenges of hot tearing at the junction between the hub and blades. In this continuation, we developed a coupled thermal fluid stress analysis model using ProCAST software to optimize the LPDC process. By adjusting casting parameters such as the melt supply temperature, initial mold temperature, and curvature radius between the hub and blades, we minimized hot tearing and other casting defects. The results were validated through simulations and practical applications, showing significant improvements in the quality and structural integrity of the propellers. Non-destructive testing using X-ray CT confirmed the reduction in internal defects, demonstrating the effectiveness of the simulation-based approach for alloy design and process optimization.

Fabrication of 3D PCL/PVP scaffolds using monosodium glutamate as porogen by solvent casting/particulate leaching method for oral and maxillofacial bone tissue engineering.

The design of three-dimensional (3D) scaffolds should focus on creating highly porous, 3D structures with an interconnected pore network that supports cell growth. The scaffold's pore interconnectivity is directly linked to vascularization, cell seeding, guided cell migration, and transportation of nutrients and metabolic waste. In this study, different types of food flavors including monosodium glutamate, sugar, and sodium chloride were used as the porogens along with PCL/PVP blend polymer for solvent casting/particulate leaching method. The morphology, porosity, interconnectivity, chemical composition, water absorption, and mechanical properties of the fabricated scaffolds are carefully characterized. The scaffolds are biocompatible in bothin vitroandin vivoexperiments and do not trigger any inflammatory response while enhancing new bone formation and vascularization in rabbit calvaria critical-sized defects. The new bone merges and becomes denser along with the experiment timeline. The results indicate that the 3D PCL/PVP scaffolds, using monosodium glutamate as porogen, exhibited suitable biological performance and held promise for bone tissue engineering in oral and maxillofacial surgery.

Characterization, mechanical properties, and wear behavior of functionally graded aluminum hybrid composite.

The present work demonstrates the development of SiC/TiS2/AlSi12Cu hybrid functionally graded composite using centrifugal casting and examines its microstructural, mechanical, and tribological properties. A gradient distribution of reinforcement particles was observed with the outer region being particle-rich. EBSD analysis confirms microstructural refinement owing to titanium's grain refining properties and the formation of θ-Al2Cu intermetallic phase. The outer layer of the composite attained a maximum hardness and tensile strength of 93 HB and 202 MPa respectively, which was increased by 7.5% and 8.2%, 20.4% and 13.8%, 22.5% and 44.5% in middle, inner, and as-received alloy respectively. Tribological properties were assessed via dry sliding pin-on-disk tribometer with various process parameters such as load (10-40 N), velocity (1-4 m/s) and distance (500-2000 m), optimized using response surface methodology. The higher wear resistance was attained by the optimized process parameters of 16 N load, 1.6 m/s velocity, and 804 m distance. Results indicated increased material loss with higher load, sliding distance, and velocity, but with enhanced wear resistance in the outer zone. Worn surface analysis revealed deeper grooves, delamination, particle pull-out, and wear tracks under severe conditions. The study emphasizes the composite's potential for high wear applications, linking its microstructural features to its superior wear behavior.

Highly Thermally Conductive and Flexible Thermal Interface Materials with Aligned Graphene Lamella Frameworks.

Highly thermally conductive and flexible thermal interface materials (TIMs) are desirable for heat dissipation in modern electronic devices. Here, we fabricated a high-crystalline aligned graphene lamella framework (AGLF) with precisely controlled lamella thickness, pore structure, and excellent intergraphene contact by manipulating the thermal expansion behavior of scanning centrifugal casted graphene oxide films. The rational design of the AGLF balances the trade-off between the thermal conductivity and flexibility of TIMs. The AGLF-based TIM (AGLF-TIM) shows a record thermal conductivity of 196.3 W m-1 K-1 with a graphene loading of only 9.4 vol %, which is about 4 times higher than those of reported TIMs at a similar graphene loading. Meanwhile, good flexibility remains comparable to that of commercial TIMs. As a result, an LED device achieves an additional temperature decrease of ∼8 °C with the use of AGLF-TIM compared to high-performance commercial TIMs. This work offers a strategy for the controlled fabrication of graphene macrostructures, showing the potential use of graphene as filler frameworks in thermal management.

Evaluation of the Effectiveness of Semolina in Improving the Bond Strength of Metal Alloys and Acrylic Resins for the Fabrication of Hybrid Prostheses for Implant Restoration: An In Vitro Study.

Introduction Fixed prosthodontic solutions for restorations of multiple implants are often done using acrylic-metal hybrid prosthesis. These restorations have a high failure rate due to poor bond strength between metal and acrylic, despite using digital attachments and primers. This study has been done to demonstrate an economical yet effective method of increasing shear bond strength between acrylic and metal. Materials and methods Disc specimens of 10 mm diameter and 2 mm thickness were designed using the Meshmixer version 3.5 software (Autodesk Inc., San Rafael, USA). The standard tessellation (STL) file was imported and sent for direct metal laser sintering (DMLS) in cobalt-chromium (CoCr), titanium (Ti), and wax milling. The groups were defined. Ten samples were included in each group. Group 1: Conventional Casting in CoCr; Group 2: Conventional Casting with Opaquer (CoCr); Group 3: DMLS CoCr; Group 4: DMLS CoCr with Opaquer; Group 5: DMLS Ti; Group 6: DMLS Ti with Opaquer; Group 7: Casting with Semolina (CoCr); and Group 8: Casting with Semolina and Opaquer (CoCr). Wax-up was performed using double wax sheet thickness of modeling wax. Flasking and acrylization were done using the injection moulding technique. A universal testing machine was used for shear bond strength. Results were tabulated and statistical analysis was done using IBM SPSS Statistics for Windows (IBM Corp., Armonk, USA). The Shapiro-Wilk test was done to confirm the normality of the data, followed by the one-way analysis of variance (ANOVA) test to compare the shear bond strength between metal alloys and heat cure acrylic resin.  Results The one-way ANOVA results reveal significant differences in bond strengths among the various groups. Conventional Casting with Opaquer showed no significant difference (p=0.335), but there were notable improvements in bond strength when compared to DMLS CoCr, DMLS CoCr with Opaquer, DMLS Ti, DMLS Ti with Opaquer, Semolina, and Semolina with Opaquer, with DMLS Ti having the largest mean difference (3.368). Conventional Casting with Opaquer significantly outperformed all groups, especially Semolina, which showed the highest mean difference (7.558). Similar trends were seen with DMLS CoCr and DMLS Ti, where Semolina consistently demonstrated superior bond strength. Overall, Semolina produced the highest bond strengths across all conditions. These results underscore the importance of material selection and treatment in enhancing bond strength. Conclusion Semolina can be used as an economical and reliable method to increase the shear bond strength between acrylic and metal bonding. Its ability to burn out during dewaxing without any remains or remnants in mould deems it a useful material for increasing mechanical bonding.

Comprehensive analysis of the rostral and caudal cerebral artery branching patterns in the dromedary camel (Camelus dromedarius).

Introduction: In mammals, the cerebral cortex depends on a robust blood supply for optimal function. The rostral and caudal cerebral arteries are critical for supplying the cerebrum. This study presents the first detailed anatomical description of the rostral and caudal cerebral arteries of dromedary camels (Camelus dromedarius), including their origins, routes, and complex branching patterns. Methods: A sample of 55 heads from male dromedary camels aged 2-6 years was analyzed using advanced casting techniques with various casting materials to provide precise visualization of these arterial structures. Results: The rostral cerebral arteries originate dorsally from the rostral epidural rete mirabile (RERM), while the caudal cerebral arteries arise from the caudal communicating artery, which is another branch of the RERM. Both sets of arteries give rise to multiple cortical branches responsible for supplying the medial aspects of the frontal, parietal, and temporal lobes, as well as the medial and caudal regions of the occipital lobes. Conclusion: This study significantly expands our understanding of the cerebrovascular anatomy of dromedary camels. Our findings have potential implications for veterinary medicine in the diagnosis and treatment of neurological disorders in camels and may offer insights into broader comparative neuroscience research.

A Long-Lasting Triamcinolone-Loaded Microneedle Patch for Prolonged Dermal Delivery.

Background: Scar is an unpleasant skin lesion that occurs following deep wounds or burns. The application of local triamcinolone is a common treatment for scar treatment and prevention, which should be repeated several times in conventional dosage forms. An effort has been made here to provide a prolonged triamcinolone dermal delivery by microneedle technology, which can also be used for wound closure. Objectives: This study aimed to develop a long-lasting polylactic acid (PLA) microneedle patch for the prolonged release of triamcinolone acetonide (TrA) that could potentially be used for closure of wound edges and scar prevention and treatment. Methods: In this study, 3% and 10% TrA-containing polymeric microneedles were fabricated using the micro molding-solvent casting method. Optical microscopy, X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC) were used for the characterization of microneedles. Mechanical strength was evaluated using a compression test and methylene blue staining. Additionally, the insertion depth was determined by histopathological sectioning of human skin samples and also insertion into Parafilm®M as a skin model. The in vitro drug release profile of the microneedles was studied over 34 days, and the kinetic model was determined. The ex-vivo skin permeation of TrA was studied using a Franz-diffusion cell. Results: The TrA-containing PLA microneedles were fabricated with a uniform structure without any failure, deterioration, or loss of needles. Fourier-transform infrared spectroscopy and differential scanning calorimetry showed no interaction between TrA and PLA, and no effect on crystallinity and thermal behavior of TrA on polymer was detected. Microneedles showed appropriate mechanical properties, which were able to penetrate to about 900 - 1000 µm depth. Release profile from the whole body of 10% and 3% microneedle fitted to Higuchi model with cumulative amounts of 625 µg and 201.64 µg over 34 days. Release from the needles followed zero-order kinetic with cumulative amounts of 30.04 µg and 20.36 µg for 10% and 3%, respectively, for 34 days. Permeation was calculated to be 17 µg/day for 10% TrA-containing microneedle. Conclusions: The results suggested that suitable PLA microneedles containing TrA with prolonged release behavior can be successfully constructed with the solvent casting method.

Seating accuracy of removable partial denture frameworks fabricated by different digital workflows in comparison to conventional workflow.

PURPOSE: To evaluate the seating accuracy of removable partial denture (RPD) frameworks fabricated by two digital workflows involving selective laser melting (SLM) in comparison to the conventional workflow. MATERIALS AND METHODS: A Kennedy class III modification 1 partially edentulous mandibular arch was used as a master model. Three RPD framework groups were included: (1) a conventional workflow group with conventional impression and casting (CC), (2) a partial digital workflow group with conventional impression and digital fabrication (CD), and (3) a complete digital workflow group with digital impression and digital fabrication (DD). A total of 10 frameworks were produced for each group. The marginal gaps at the occlusal rests, retention arms, and reciprocating arms were measured by a traveling microscope. The data were analyzed with the one-way analysis of variance test. RESULTS: At the framework level, the most superior fit was observed for the CD group (79.5 µm) followed by DD (85.3 µm) and CC (114.2 µm) groups. The CD and DD groups were significantly superior to CC (p < 0.001). This fit pattern was consistent for the retention and reciprocating arms, while the occlusal rest fit was similar among all the groups. CONCLUSIONS: The SLM frameworks had a promising seating accuracy in comparison to conventional frameworks. The type of impression, conventional or digital, did not affect the accuracy of SLM frameworks. The differences observed in the present study are likely to be of minimal clinical significance.

Current Concepts in the Treatment of Early Onset Scoliosis.

Despite many surgical advances in the treatment of early onset scoliosis (EOS) over the past two decades, this condition remains a challenge to address. While otherwise healthy children can have EOS, many of these patients have complicated comorbidities making proper treatment algorithms extraordinarily difficult. Non-operative measures can be successful when initiated early, but are many times utilized as a delay tactic until growth-friendly operative procedures can be safely performed. This article will summarize the current concepts in the treatment of EOS with a focus on the surgical advances that have recently been made.

Effect of the molar mass of chitosan and film casting solvents on the properties of chitosan films loaded with Mentha spicata essential oil for potential application as wound dressing.

Chitosan based films endowed with antibacterial features have witnessed remarkable progress as potential wound dressings. The current study aimed at appraising the effects of the molar mass of chitosan (MM) and the film casting acids on the properties of unplasticized chitosan films and plasticized MSO-embedded chitosan films in order to provide best suited film formulation as a potential candidate for wound dressing application. The prepared films were functionally characterized in terms of their qualitative assessment, thickness, density, swelling behavior, water vapor barrier, mechanical and antibacterial properties. Overall, all chitosan films displayed thickness lower than the human dermis even though thicker and denser films were produced with lactic acid. Assessment of the swelling behavior revealed that only high molar mass (HMM) chitosan films may be regarded as absorbent dressings. Moreover, unplasticized HMM lactate (HMM-LA) films furnished lower stiffness and higher percent strain break as compared to acetate films, due to the plasticizing effect of the remaining lactic acid as alluded by the FTIR analysis. Meanwhile, they provided suitable level of moisture and indicated substantial antibacterial activity against S. aureus and E. coli, the most commonly opportunistic bacteria found in infected skin wound. Plasticized chitosan films doped with MSO were significantly thicker and more permeable to water compared to unplasticized films. Furthermore, MSO significantly potentiate the antibacterial effect of chitosan-based films. Therefore, plasticized HMM-LA/MSO chitosan film flashing good swelling behavior, adequate WVTR and WVP, suitable mechanical properties and antibacterial performances substantiated to be a promising antibacterial dressing material for moderately exuding wounds.

Bioactive material­sodium alginate-polyvinyl alcohol composite film scaffold for bone tissue engineering application.

Road accidents and infection-causing diseases during bone surgery are serious problems in orthopedics, and thus, addressing these pressing challenges is crucial. In the present study, the 70S30C calcium silicate bioactive material (BM) is synthesized by a sustainable approach employing a precipitation method using recycled rice husk and eggshells as a precursor of silica and calcium. Further, 70S30C BM is composited with sodium alginate (SA) and polyvinyl alcohol (PVA), and the films were prepared by solvent casting method. The composite films were prepared without the addition of acid, binder, and crosslinking agents. Further, the films were characterized by BET, XRD, ATR-FTIR, SEM, and EDS mapping. The in vitro bioactivity and biodegradation study is performed in the simulated body fluid (SBF). The in vitro haemolysis study is executed using human blood and the results demonstrate haemocompatibility of the composite films. The ex ovo CAM assay also exhibits good neovascularization. The in vitro and in vivo biocompatibility assay proves its non-toxic nature. Further, the in vivo study reveals that the engineered composite film demonstrates accelerated osteogenesis. This work broadens the orthopedic potential of the composite film and offers bioactivity, haemocompatibility, angiogenesis, non-toxicity, and in vivo osteogenesis which would serve as a potential candidate for bone tissue engineering application.

Sub-Micron Replication of Fused Silica Glass and Amorphous Metals for Tool-Based Manufacturing.

The growing importance of submicrometer-structured surfaces across a variety of different fields has driven progress in light manipulation, color diversity, water-repellency, and functional enhancements. To enable mass production, processes like hot-embossing (HE), roll-to-roll replication (R2R), and injection molding (IM) are essential due to their precision and material flexibility. However, these processes are tool-based manufacturing (TBM) techniques requiring metal molds, which are time-consuming and expensive to manufacture, as they mostly rely on galvanoforming using templates made via precision microlithography or two-photon-polymerization (2PP). In this work, a novel approach is demonstrated to replicate amorphous metals from fused silica glass, derived from additive manufacturing and structured using hot embossing and casting, enabling the fabrication of metal insets with features in the range of 300 nm and a surface roughness of below 10 nm. By partially crystallizing the amorphous metal, during the replication process, the insets gain a high hardness of up to 800 HV. The metal molds are successfully used in polymer injection molding using different polymers including polystyrene (PS) and polyethylene (PE) as well as glass nanocomposites. This work is of significant importance to the field as it provides a production method for the increasing demand for sub-micron-structured tooling in the area of polymer replication while substantially reducing their cost of production.

Stretch-Induced Spin-Cast Membranes Based on Semi-Crystalline Polymers for Efficient Microfiltration.

Microfiltration membranes derived from semi-crystalline polymers face various challenges when synthesized through the extrusion-casting technique, including the use of large quantities of polymer, long casting times, and the generation of substantial waste. This study focuses on synthesizing these membranes using spin-casting, followed by stretch-induced pore formation. Recycled high-density polyethylene (HDPE) and virgin polyethylene powder, combined with a calcium carbonate filler, were used as the source materials for the membranes. The influence of the polymer-filler ratio with and without stretching on the morphology, tensile strength, and water flow rate was investigated. Optimal conditions were determined, emphasizing a balance between pore structure and mechanical integrity. The permeable membrane exhibited a water flow rate of 19 mL/min, a tensile strength of 32 MPa, and a water contact angle of 126°. These membranes effectively eliminated suspended particles from water, with their performance evaluated against that of commercially available membranes. This research, carried out utilizing the spin-casting technique, outlines a synthesis route for microfiltration membranes tailored to semi-crystalline polymers and their plastic forms.