Superior Mechanical Performance Research Articles

Muscle‐Inspired Robust Anisotropic Cellulose Conductive Hydrogel for Multidirectional Strain Sensors and Implantable Bioelectronics

AbstractIntegrating superior mechanical performance, anisotropic conductivity, and biocompatibility into conductive hydrogels as all‐in‐one human‐machine interaction device remains challenging. Herein, by mimicking the anisotropic structures of human muscles, a robust anisotropic conductive hydrogel is developed by initially aligning polyvinyl alcohol with polypyrrole decorated cellulose nanofibrils to form an anisotropically oriented polymer networks, followed by post‐crosslinking with tannic acid (TA). Introducing TA into hydrogel network permanently secures its hierarchically anisotropic structure through multiple hydrogen bonds, thus endowing the hydrogel with exceptional mechanical properties (tensile strength of 11.41 MPa, toughness of 12.44 MJ m−3), anisotropic adhesive property, and direction‐dependent conductivity. With these attributes, a hydrogel strain sensor with excellent multidirectional sensitivity is developed, enabling stable monitoring of multi‐degrees of freedom joint movements in the human body and facilitating the control of a multiaxial virtual robot manipulator. Moreover, the in vitro/vivo tests demonstrate exceptional biocompatibility and anti‐biofouling properties of the as‐prepared hydrogel sensor, maintaining stable electronic response signals for over 14 days after successful implantation into the Achilles tendon of mice. Overall, this study presents a promising approach for designing conductive hydrogels with superior mechanical properties and anisotropic functionality for emerging applications in both in vitro and in vivo human‐machine interface materials.

Multi‐Channel Optical Encryption Film With Strong Circularly Polarized Luminescence and High Quantum Yield

AbstractDeveloping a sustainable security module with multiple optical states is important to deter counterfeits, but is challenging. This work designs a kind of chiral luminescent film through the co‐assembly of the CNCs and d‐glucose, simultaneously doped with the lanthanide complex and organic dye. Superior mechanical performance makes it undertake various deformations, including twist, and tension without breaking. Meanwhile, this film has unique optical characteristics. On the one hand, the chiroptical signals can be manipulated through the matching of the photonic bandgap and fluorescence peak. On the other hand, due to the co‐assembly with two luminophores, the film displays the excitation wavelength (Ex)‐dependent circularly polarized luminescence properties. Under the Ex of 275 nm, the film simultaneously integrates a large dissymmetry factor of −0.3898, a high quantum yield of 69.19%, and a considerable lifetime of 1381 µs, which has exceeded most reported chiral luminescent assemblies. These multimodal and convertible optics endow the film with practical applications in the anti‐counterfeit. It can be designed as a security label or used as a written paper to encrypt the information. Even in humid surroundings, this security effect is still ensured.

Mechanical and economical feasibility of LDPE Waste-modified asphalt mixtures: pathway to sustainable road construction

This research study evaluates the impact of low-density polyethylene (LDPE) modified asphalt binder on the mechanical performance and economical feasibility of asphalt concrete (AC) mixtures. LDPE-modified mixtures were compared with conventional mixes prepared with various binders commonly used in India, i.e., VG 30, VG 40, Polymer-Modified Binder (PMB), and Crumb Rubber Modified Binder (CRMB). LDPE-modified mixtures exhibit superior mechanical performance, increasing the stiffness of AC mixtures by 171% and 125% at 25 °C and 35 °C, respectively, compared to VG 30 base binder. Additionally, the indirect tensile strength (ITS) improved by 51% over VG 30. LDPE-modified mixtures also showed improved resistance to permanent deformation, with RTIndex values up to 133.46% higher than VG 30, and higher fatigue resistance, as indicated by increased CTIndex values compared to VG 30 and CRMB. However, the CTIndex values for LDPE-modified mixtures were 26.32% and 56% lower than those for VG 40 and PMB, respectively. Pavement analysis using 3D-Move showed lesser deflections at pavement layer interfaces, resulting in higher rutting and fatigue life for LDPE-modified pavements. Furthermore, LDPE-modified pavements showed up to 57% higher fatigue life (Nf) and up to 42.33% higher rutting life (Nr) than other pavements. The economic analysis showed that the cost of LDPE-modified pavements is comparable to VG 40 and around 10% more economical than pavements containing PMB. Using LDPE also offers environmental benefits by repurposing up to 750 kg for every kilometer of single-lane pavement section having 50mm thick surface course. Overall, LDPE-modified asphalt mixtures present a sustainable and high-performance solution for asphalt pavement construction.

Mechanism analysis of dual wavelength laser welding AlN-PC joint based on microtexture treatment

High-strength interfacial bonding between ceramics and transparent polymers is hardly to be achieved, especially in the field of optical packaging of biochips. This paper proposes a novel laser welding method that enhances the joint strength between aluminum nitride (AlN) ceramic and polycarbonate (PC) by laser surface microtexturing. The study investigates the influence of welding methods and microtextures on welding effectiveness, elucidating the bonding mechanisms of the joints. The obtained results showed that dual wavelength laser welding effectively achieves the connection between AlN ceramic and PC. Laser microtexturing increases surface roughness and contact area, leading to stronger mechanical interlocking and overall joint strength. The highest shear strength reached up to 14.66 MPa with longitudinal grooves microtexture. The laser microtexturing improves the hydrophilicity of the AlN surface, facilitating more effective bonding between the materials. The bonding mechanisms at the joint interface include both mechanical interlocking and chemical bonding. Microtexturing improves the stress distribution at the joint interface. The formation of C-O-Al chemical bonds at the interface effectively enhances the joint strength. Longitudinal grooves microtexture exhibit a higher substrate fracture rate due to stress concentration and capillary pores. In contrast, staggered square holes microtexture provide superior mechanical performance through uniform stress distribution and robust mechanical interlocking.

Tailoring the Mechanical Properties and Foaming Behaviors of PLA/P4HB Blends by Using P4HB‐g‐GMA as Compatibilizer

ABSTRACTSynthetic poly(4‐hydroxybutyrate) (P4HB), a flexible and biodegradable polymer, shows great promise in improving the toughness of poly(lactic acid) (PLA), but the inherent immiscibility of PLA and P4HB compromises the toughening efficiency. To address this issue, P4HB grafted glycidyl methacrylate (P4HB‐g‐GMA) is synthesized for the purpose of enhancing the compatibility within the PLA/P4HB blend. The epoxy groups on P4HB‐g‐GMA can form strong chemical bonds with PLA chains and remain compatible with P4HB. Rheological data confirm that adding P4HB‐g‐GMA enhances polymer chain entanglement. Therefore, the phase interface of the blend becomes more diffuse, leading to improved mechanical performance. Specifically, a 3D‐printed PLA/P4HB/P4HB‐g‐GMA blend containing 8% P4HB‐g‐GMA (PLA/P4HB/G8) achieves an elongation at break of 161.5%, approximately 22.7 times higher than that of a PLA/P4HB blend without the modifier. Moreover, the PLA/P4HB/G8 blends show a higher volume expansion ratio (VER) and better cell morphology due to the increased melt strength from P4HB‐g‐GMA. This study demonstrates a simple and efficient method to improve the compatibility between PLA and P4HB, resulting in superior mechanical performance of PLA/P4HB blends and broadening their potential applications in foaming.

Natural and synthetic fiber reinforced recycled aggregate concrete subjected to standard fire temperature

The increasing scarcity of natural materials and rising construction costs have prompted the need for alternative materials that can match the performance of conventional aggregates. This study explores the use of recycled aggregate concrete (RAC) as a sustainable alternative, supplemented with natural and synthetic fibers to overcome the inherent strength limitations caused by the residual cement paste on the aggregate surface. To enhance the mechanical and thermal stability of RAC, steel, polypropylene, and coconut fibers were incorporated. The rheological, hardened, and post-fire properties of fiber-reinforced RAC were thoroughly investigated. After 28 days, the porosity of RAC with fiber reinforcement was observed to be less than 2 %. The concrete was also exposed to elevated temperatures as per ISO 834 guidelines to assess its thermal performance. Key parameters such as mass loss, crack width, porosity, and strength degradation were analyzed. Image analysis was used to track surface modifications and measure surface porosity after heating. Among the fiber types, steel fiber reinforced concrete exhibited superior mechanical and thermal performance, followed by coconut fiber reinforced concrete, making coconut fibers a viable natural alternative to synthetic fibers. RAC without fibers displayed the highest porosity (20 % and 32 %) after exposure to 821 °C and 1029 °C, respectively. Strength degradation ranged from 40 to 50 % after heating to 821 °C, increasing to 74–80 % at 1029 °C, irrespective of fiber type. This research highlights the potential of fiber-reinforced RAC for structural applications, offering a sustainable solution with comparable strength and durability to conventional concrete.

A comprehensive experimental study of eco-friendly hybrid polymer composites using pistachio shell powder and Aquilaria agallocha Roxb

This study investigates the effects of incorporating pistachio shell powder and a mixture of Aquilaria agallocha Roxb (AAR) resin with epoxy on the mechanical, dynamic mechanical, thermal, and biodegradability properties of an epoxy composite. Filler loadings ranged from 10 to 35% by volume, in 5% increments. Scanning electron microscopy (SEM) revealed a uniform distribution of the hybrid polymer materials, particularly at 30% natural resin content, enhancing the load-bearing capacity of the composites. The addition of pistachio shell powder and AAR resin significantly improved the flexural modulus and strength of the composites. At a filler volume of 35%, the hybrid polymer exhibited a maximum impact resistance of 2,718 J/m2, demonstrating increased energy absorption. Moreover, the hybrid system enhanced the damping factor by up to 30%, suggesting superior dynamic mechanical performance. Thermogravimetric analysis (TGA) indicated that the hybrid composites displayed better thermal stability compared to pure epoxy resin. These findings suggest that the combination of pistachio shell powder and AAR natural resin offers a sustainable approach to reinforcing epoxy-based composites, providing improved mechanical and thermal performance for potential industrial applications.

Synthesis and Characterization of Poly (Erythritol Sebacate)

AbstractErythritol is a sweetener polyol widely distributed in nature. Its industrial production is based on biotechnological fermentative processes using yeasts. It is used essentially in nutrition and pharmaceutical fields. However, due to its still high price, the use of erythritol is not widespread and is lower than that of other polyols. The use of erythritol for polymer synthesis remains largely unexplored by the scientific community. This work describes the synthesis and characterization of polyester, poly (erythritol sebacate) (PES), obtained by thermal polycondensation of erythritol and sebacic acid in a two steps approach. A prepolymerization step was realized at different temperatures (150 °C, 160 °C and 170 °C, respectively) followed by a cure step at 150 °C. It was found that using a higher temperature allows the same degree of polymerization (50%) to be achieved in a shorter period, but this leads to prepolymers with a more heterogeneous oligomeric composition. This is reflected in the final properties of the polymers after curing. Synthesis at 150 °C produced a polymer with superior mechanical performance (ultimate tensile strength: 0.5 MPa; Young’s modulus: 0.44 MPa: elongation at break: 123%) and higher chemical resistance to solvents than polymers synthesized at 160 °C and 170 °C. The glass transition temperature (Tg) is between − 20 and 0 °C for all polymers and density is 1.08 g/cm3. Based on these results, we believe that PES is a good elastomer with tunable properties and potential for selective absorption of molecules, such as ethanol, that could be useful for beverage industry and biotechnological applications. Graphical Abstract

Concurrently Improving both Mechanical and Electrochemical Performances of Quasi-Solid-State Electrical Double-Layer Capacitors by a Rational Design of Gel Polymer Electrolytes.

Aqueous poly(vinyl alcohol) (PVA) gel electrolyte-based quasi-solid-state electrical double-layer capacitors (QSEDLCs) have been extensively investigated in the past ten years, but challenges remain to fabricate the PVA gel electrolyte possessing both superior mechanical and outstanding electrochemical performances. Herein, we develop a strategy to address this issue by a rational design of PVA gel electrolytes, based on a combination of the freeze-thaw (FT) method and sodium perchlorate (NaClO4)-based water-in-salt (WIS) electrolyte. Our study demonstrates that either the FT method or the NaClO4-based WIS electrolyte can improve both the mechanical performance of the PVA gel electrolyte by increasing the crystallization of PVA chains and the electrochemical performance of the PVA gel electrolyte-based QSEDLC by different mechanisms. In comparison with the conventional solvent evaporation method, this work provides an effective strategy to concurrently improve both the mechanical and electrochemical performances of aqueous QSEDLCs.

Flexural cracking behavior of steel-NC-UHPC composite beam under negative bending moment

Steel-concrete structures are widely applied in bridge engineering due to their superior mechanical performance and cost-effectiveness. However, normal concrete (NC) decks often suffer cracking problems, adversely affecting their serviceability. Ultra-high performance concrete (UHPC) can be used to partially replace the top of NC decks to enhance their post-cracking behavior because UHPC shows high tensile strength, strain-hardening characteristics in tension, and strong bond strength with NC. To this end, this paper focused on the flexural behavior of steel-NC-UHPC composite beams regarding their failure mode, stiffness, strain development, cracking behavior, crack width, etc. Test results indicated that the test specimens mainly exhibited two types of failure modes: shear failure of the NC layer and local buckling of the compressive flange at the steel girder, which were mainly determined by the reinforcement ratio. Flexural stiffness was controlled by the steel girder, and the reinforcement ratio had a notable effect on the reinforcement strain and crack propagation. Additionally, cracks can be categorized into three types: through cracks, connecting cracks, and separate cracks. These cracks in the UHPC layer and NC layer would affect each other, especially those near the roughening interface. The sectional nonlinear analysis was employed to calculate the strain of reinforcement and the steel girder accurately. Finally, the prediction methods of crack width for the NC layer and UHPC layer were discussed. Formulas in NF P18–710 were verified to be feasible for the prediction of UHPC crack width. The UHPC influence factor was introduced to modify the calculation results of the NC crack width by the Chinese NC code.

Achieving ZT > 1 in Cu and Ga Co-doped Ag6Ge10P12 with Superior Mechanical Performance and Its Fundamental Physical Properties toward Practical Thermoelectric Device Applications.

Recently, phosphorus-based compounds have emerged as potential candidates for thermoelectric materials. One of the key challenges facing this field is to achieve ZT > 1, which is the benchmark for thermoelectric device applications. In this study, it is demonstrated that the thermoelectric performance of environmentally friendly Ag6Ge10P12 is enhanced by co-doping Cu and Ga. The mechanical properties, coefficient of linear thermal expansion, work function, and compatibility factor are comprehensively clarified to provide guidelines for reliable device applications. The peak and average dimensionless figures of merit of Ag5.85Cu0.15Ge9.875Ga0.125P12 reach 1.04 at 723 K and 0.63 at 300-723 K, respectively, which are the highest values for phosphorus-based thermoelectric materials. The Young's modulus, Vickers microhardness, fracture toughness, and compressive strength of Ag5.85Cu0.15Ge9.875Ga0.125P12 are 132 GPa, 589, 1.23 MPa m1/2, and 219 MPa, respectively, which are superior to those of typical state-of-the-art thermoelectric materials. The remarkable thermoelectric and mechanical performance of Ag5.85Cu0.15Ge9.875Ga0.125P12 mean that it is a promising candidate for medium-temperature thermoelectric conversion. Ti, V, Rh, and Pt are suitable for electrodes without exfoliation under thermal expansion and with ohmic contacts to Ag5.85Cu0.15Ge9.875Ga0.125P12 in terms of the coefficient of linear thermal expansion and work function. Considering that the compatibility factor of Ag5.85Cu0.15Ge9.875Ga0.125P12 is approximately 2.8, half-Heusler, skutterudite, and magnesium silicide-stannide compounds are suitable n-type thermoelectric counterpart materials in thermoelectric devices. These insights will lead to the development of phosphorus-based thermoelectric materials toward practical thermoelectric device applications.

Covalent and non‐covalent action‐enhanced cellulose‐based thermally conductive composite (TCC) films fabricated via vacuum‐assisted self assembly with high thermally conductivity and superior mechanical performance

AbstractAs is known, to establish covalent or non‐covalent interaction between filler and matrix, which helps to reduce the interface thermal resistance (ITR) as well as construct good thermal conduction channels, is a good strategy for dealing with the risk of thermal runaway in the extreme service environment of electronic equipment. In this paper, carboxylated nanocellulose fiber (c‐CNF) was used as matrix, and a hybrid filler (M‐CoNPs@GNP) was fabricated by coating cobalt‐nanoparticles (CoNPs) and grafting maleimide on graphene nanosheets (GNPs). M‐CoNPs@GNP/c‐CNF thermally conductive composite (TCC) films were successfully fabricated by combining with c‐CNF. As zero‐dimensional particles, CoNPs can effectively prevent GNPs agglomeration due to surface effects, and “‐NH” in maleimide dehydrates with “‐COOH” in c‐CNF to form “C‐N‐C” covalent bonds, with strong hydrogen bond formed between filler and matrix, which remarkably enhances the interface compatibility between matrix and filler. The ITR has been reduced to form a well‐defined three‐dimensional thermal conduction path, achieving an ultra‐high in‐plane TC (35.9 W·m−1·K−1) for MCGC40, which is 7.9 times that of pure c‐CNF film, in addition to a sufficiently high tensile strength of 123.3 MPa. The combination of high in‐plane TC, excellent mechanical flexibility and good electrical insulation jointly justifies the potential application of M‐CoNPs@GNP/c‐CNF TCC films in effective thermal management of flexible electronic products.Highlights CoNPs effectively inhibit GNPs agglomeration. GNPs exhibit hydrophilicity after modification. Modified fillers interact fairly well with the matrix. High tensile strength and exceptional flexibility are achieved. TCC films exhibit both electrical insulation and hydrophobicity.

A critical review of composite filaments for fused deposition modeling: Material properties, applications, and future directions

This review paper provides a comprehensive analysis of recent advancements in the development and application of composite filaments for fused deposition modeling (FDM) 3D printing technology. Focusing on the integration of various materials such as nano-fillers, fibers, and bio-based polymers into polylactic acid (PLA) and other thermoplastics, this study delves into how these composites enhance mechanical, thermal and functional properties of the printed objects. We critically assess studies that investigate the impact of raster orientation, filler content, and material composition on tensile, bending, and impact strength, as well as on the thermal stability and degradation behavior of composite filaments. The review highlights key findings from the literature, including the optimization of filament formulations to achieve superior mechanical performance, improved thermal resistance, and specific functional characteristics suitable for a wide range of applications from biomedical to structural components. Moreover, this paper discusses the challenges associated with composite filament production, including material compatibility, dispersion of nano-fillers, and the need for printer hardware adjustments. Future directions for research in the field are identified, emphasizing the potential for new material combinations, sustainability considerations, and the development of filaments designed for specific industrial applications. An effective way to better meet designers’ expectations for qualified materials is composite filaments. This review focuses on how these elements can be applied to improve both product design and functionality. A guide is presented in choosing composite filaments that can meet the features expected from the designed product.

Influence of hybrid additive manufacturing processes on the microstructure and mechanical properties of maraging steel 1.2709 components with post-processing heat treatments

The microstructural analysis revealed that the hybrid manufacturing process, combining Powder Bed Fusion (PBF) and Directed Energy Deposition (DED), resulted in a refined grain structure with a uniform phase distribution in the Maraging Steel 1.2709 components. The post-processing heat treatments, specifically stress relief at 500 °C for 2 h and solution treatment at 850 °C for 2 h, significantly enhanced the material’s mechanical properties. The components exhibited increased hardness and improved tensile strength, attributed to the effective elimination of residual stresses and the promotion of desirable precipitate formation during heat treatment. Overall, the study demonstrated that the hybrid PBF-DED process, coupled with appropriate heat treatments, can produce maraging steel components with superior mechanical performance, making them suitable for high-stress applications in advanced manufacturing sectors.

Investigating the Corrosion Inhibition Performance of a Novel Coconut Oil-Based Poly(urethane-urea) Hybrid Coating on Carbon Steel in 3.5% NaCl Solution

Polyurethane has been used for years as an anti-corrosion coating due to its intrinsic hydrophobic properties. However, its hydrophobicity is not enough to inhibit the permeation of corrosive agents; thus, incorporating it with polyurea would further enhance its hydrophobic properties. In this study, coconut oil, a saturated, low molecular weight vegetable oil, was employed as an eco-friendly precursor for synthesizing a novel poly(urethane-urea)- based hybrid coating. The synthesis process involved the utilization of a coconut oil-based polyol blend, triethanolamine (TEA) as an amine source, and hexamethylene diisocyanate (HDI). The resulting hybrid coating on carbon steel demonstrated remarkable anticorrosion performance in a 3.5 wt. % NaCl solution, owing to the intrinsic hydrophobic characteristics of coconut oil and polyurea. Significant corrosion rate reduction was observed with increasing amine content, accompanied by an enhancement in mechanical properties. Notably, an amine loading of 4% consistently exhibited superior corrosion resistance and mechanical performance in the hybrid coating. Chemical structural analysis revealed a hydrogen-bonding network in polyurea coatings, reducing porosity, enhancing barrier properties, and improving mechanical characteristics, highlighting its potential for sustainable corrosion protection.

Influence of Oxygen and Nitrogen Flow Ratios on the Microstructure Evolution in AlCrTaTiZr High-Entropy Oxynitride Films

This study explores the influence of oxygen and nitrogen flow ratios on the microstructure and mechanical properties of AlCrTaTiZr high-entropy oxynitride films. Oxygen flow rates (0%–0.75%) were adjusted while maintaining a fixed nitrogen flow ratio (RN = 15%) to fabricate films with similar compositions. The results show that increasing oxygen flow enhanced hardness through solid solution strengthening and grain refinement, though excessive oxygen caused an amorphous structure and reduced hardness. After annealing at 900 °C, the hardness of all films was further increased. The film with a nitrogen flow ratio 40 times higher than oxygen exhibited the highest hardness of 21.8 GPa, along with superior mechanical performance. These findings highlight the potential of high-entropy oxynitride films for applications requiring high wear resistance and adhesion.

Assessment of ply thickness and aluminum foils interleaving on the impact response of CFRP composites designed for cryogenic pressure vessels

Carbon fiber reinforced polymer (CFRP) proved to be the best choice to produce cryogenic pressure vessels coupling a reduced weight with superior mechanical performance. Despite this, CFRPs are prone to fuel leakage due to interconnected matrix cracks resulting from mechanical and thermal stresses. Two strategies were combined in this work to reduce fuel permeability, i.e., increase of plies number and metallic film interleaving, evaluating the cryogenic impact response of these new configurations. At first, the only ply thickness effect was assessed and the hybrid sandwich-like (SL) configuration with traditional CFRP (RC) skins and a thin-ply (TP) core displayed impact and residual flexural properties close to RC ones. Then, the effect of aluminum foils interleaving was investigated, and the interleaved SL configuration displayed higher residual flexural properties than interleaved RC for all temperatures, e.g., the residual flexural strength was 30.3 % higher at room temperature and 14.6 % higher at −70 °C, respectively.

Molecular dynamics modelling of the stress–strain response of [formula omitted]-sheet nanocrystals

Molecular dynamics simulations were conducted on two model antiparallel β-sheet crystallites [GA]n and [GAS]n to study deformation in chain, sheet stacking, and hydrogen bonding directions under uniaxial loading. In chain direction, both models were mechanically stable, even beyond the 570 K amorphousation temperature of silk fiber; however, [GA]n model displayed higher yield strain, stress, elastic modulus, and resilience than [GAS]n. In transverse directions, they had similar stress–strain behavior and demonstrated significant anisotropic mechanical behavior. Hence, inclusion of an amino acid with a rich side chain group extending between β-sheets reduces the stiffness of crystallite in chain direction. Serine and alanine residues maintained existing H-bonds and established new ones during stretching in chain direction and shrinking in transverse directions which affected the mechanical response near the yield point. Comparison between β-sheet crystallite and PPTA (Kevlar) showed that the mechanical performance of these crystal polymers were very similar in chain direction, but contrarily β-sheet crystallite had higher stiffness in H-bonding and sheet stacking directions than PPTA. This study may provide a guideline in designing of polyaminoacid based biocompatible materials with superior mechanical performance.

Nanofiber-Based Drug Delivery Systems: A Review on Its Applications, Challenges, and Envisioning Future Perspectives.

Nanomaterials, especially nanofibers, hold considerable promise as drug delivery systems (DDS) by providing targeted administration of drugs due to their unique properties, such as large surface area, high porosity, and mechanical robustness. Nanofibers can be fabricated using various techniques like electrospinning, self-assembly, phase separation, and template synthesis, offering properties such as adjustable size, shape, high precision, and biodegradability. Additionally, features such as multiple target functionalization, controlled release of the drug, and prolonged circulation of the drug make nanofibers particularly suitable for biomedical applications, including drug delivery, tissue regeneration, and biosensing. This comprehensive review explores the characteristics, types, fabrication methods, and applications of nanofibers. Diverse types of polymer nanofibers are used in drug delivery, such as blended nanofibers, core-shell nanofibers, and layer-by-layer assembly, each demonstrating their own advantages in controlled drug release and targeted therapy. Electrospun nanofibers are extensively utilized in biomedical applications due to their superior mechanical performance and high porosity and advancements in coaxial electrospinning enabling the fabrication of core-shell nanofibers, offering controlled drug release kinetics and protection of loaded molecules. These nanofibers demonstrate enhanced bioactivity and biocompatibility and can find application in tissue engineering. Furthermore, this review addresses the challenges associated with nanofiber production, including reproducibility and scalability. Nanofibers exhibit the potential to revolutionize medical treatment across diverse therapeutic areas. Future research directions and challenges in nanofiber-based drug delivery discussed in this review offer guidance for further advancements in this rapidly evolving field.

Making High Thermoelectric and Superior Mechanical Performance Nb0.88Hf0.12FeSb Half-Heusler via Additive Manufacturing.

Thermoelectric generators held great promise through energy harvesting from waste heat. Their practical application, however, is greatly constrained by poor raw material utilization and tedious processing in fabricating desired shapes. Herein, a state-of-the-art process is reported for 3D printing the half-Heusler (Nb0.88Hf0.12FeSb) thermoelectric material using laser powder bed fusion (LPBF). The multi-dimensional intra- and inter-granular defects created by this process greatly suppress thermal conductivity by providing numerous phonon scattering centers. The resulting LPBF-fabricated half-Heusler exhibits a high figure of merit ≈1.2 at 923K and a single-leg maximum efficiency of ≈3.3% at a temperature difference (ΔT) of 371K. Hafnium oxide nanoparticles generated during LPBF effectively prevent crack propagation, ensuring competent mechanical performance and reliable thermoelectric output. The findings highlight the significant potential of LPBF in driving the next industrial revolution of highly efficient and customizable thermoelectric materials.