Search Results (49)

The fabrication of high-resolution and mechanically robust copper patterns remain a critical challenge in flexible electronics. Here, we present a universal metallization strategy that combines sequential two-step laser transfer, including laser-induced backward transfer and laser-induced forward transfer, with subsequent electroless copper plating. In this approach, laser-induced backward transfer first generates a transferable copper particle donor layer; subsequently, laser-induced forward transfer selectively embeds these catalytic copper particles into the surface of target substrates, constructing spatially confined activation networks while minimizing direct thermal exposure. These embedded seeds are then amplified into continuous copper conductors via electroless copper plating, achieving a high-resolution pattern (average minimum linewidth of approximately 20 μm) with robust interfacial integrity. Benefiting from laser-induced mechanical interlocking, the resulting copper patterns exhibit a low electrical resistivity of ~2.0 × 10⁻⁸ Ω·m (comparable to bulk copper) and maintain stable electromechanical performance even after 8000 bending cycles across a radius range of 3 to 6 mm. Furthermore, the fabricated versatile electrodes are successfully integrated into a triboelectric nanogenerator for tactile sensing and Morse code transmission. With its inherent substrate universality (e.g., polyimide, wood, fabric, and paper) and process scalability, this strategy provides a versatile route for manufacturing reliable copper electrodes in next-generation flexible electronic systems. Full article

The generation of high-purity hydrogen via chemical reaction from hydrogen-rich materials is one of the ways in the alternative energy industry. In this approach, the utilization of catalytic materials that possess the capacity to initiate the decomposition of the starting material and the subsequent release of hydrogen is of paramount importance. In this study, nickel/cobalt-plated copper catalysts (NiCo/Cu) are presented, comprising from 4 to 90 wt.% of cobalt as catalytic materials for hydrogen generation via sodium borohydride (NaBH₄) hydrolysis reaction. The NiCo/Cu catalysts were synthesized via electroless deposition from glycine-based baths, utilizing Ni²⁺ and Co²⁺ ions as metal sources and morpholine borane (MB) as the reducing compound. The catalytic performance in alkaline NaBH₄ hydrolysis was found to correlate with the cobalt loading in the coating. The maximum rate of hydrogen production, which was determined to be 14.22 L min⁻¹ gcat⁻¹, was achieved at 343 K for a catalyst composed of 90 wt.% Co. The reaction proceeded with the activation energy of 52.5 kJ mol⁻¹, while the catalyst exhibited high durability, preserving nearly 88% of its initial activity after five successive reaction cycles. The combination of nickel and cobalt, along with their synergistic effect and high efficiency in the borohydride hydrolysis reaction, makes them promising catalysts. Full article

Mg-Zn-Ca bulk metallic glasses (BMGs) have attracted significant attention in the field of biodegradable metallic biomaterials due to their desirable in vivo degradability and high strength. However, their relatively high brittleness limits further practical applications. In this work, porous Fe skeleton-reinforced Mg-Zn-Ca bulk metallic glass composites (BMGCs) were fabricated by pressure infiltration using porous Fe skeleton as the toughening phase and Mg₆₆Zn₃₀Ca₃Sr₁ alloy as the matrix. It was found that electroless copper plating improved the interfacial wettability between molten Mg and Fe, as well as the infiltration-forming capability of the BMGCs. Quasi-static compression tests showed that the BMGC exhibited a compressive strength of 500 MPa, a plastic strain of 0.2%, and a yield strength of 420 MPa, representing a significant improvement over the matrix BMG alloy. The fracture surface displayed a vein-like pattern, indicating a noticeable transition from brittle to ductile fracture behavior. Thus, the porous Fe skeleton-reinforced Mg-Zn-Ca BMGC shows promise as a potential biodegradable biomedical material. Moreover, the preparation route presented here offers a new perspective for developing degradable Mg-Zn-Ca-based BMGCs. Full article

When fabricating high-entropy alloy particle-reinforced metal matrix composites via friction stir processing, the relatively low heat input led to insufficient interfacial diffusion between the particles and matrix, thereby compromising the composite properties. To address this issue, this study introduced an electroless copper plating step followed by heat treatment to produce Cu-coated HEA particles with an interfacial diffusion layer. These modified particles were then incorporated into a copper matrix via friction stir processing to form composites with an intentionally designed interfacial diffusion layer. The results indicate that the diffusion layer structure contributed to excellent interfacial bonding. The resulting composite exhibited a simultaneous enhancement in both strength and ductility. The tensile strength and elongation reached 372.5 MPa and 34.2%, respectively, representing increases of 20.4% and 54% compared to pure copper. The wear rate of the composite reduced by 33.7% relative to pure copper. Quantitative analysis indicated that the contribution of fine-grain strengthening, Orowan strengthening, dislocation strengthening, and load transfer strengthening to the overall strength was 41.2 MPa, 0.3 MPa, 12.7 MPa, and 15.7 MPa, respectively. Full article

The Ni-Fe coatings modified with AuNPs were deposited on the flexible copper-coated polyimide (Cu/PI) surface using electroless metal plating, while the galvanic displacement technique was applied to modify the surface of NiFe coatings by a small content of AuNPs in the range of 16.5 µg_Au cm⁻². AuNPs of a few nanometers in size were deposited on the NiFe/Cu/PI surface by immersing it in a solution containing AuCl₄⁻ ions. The electrooxidation of sodium borohydride was evaluated in a 1 M NaOH solution containing 0.05 M of sodium borohydride using cyclic voltammetry, chronoamperometry, and chronopotentiometry. In addition, the performance and stability of the NiFe/Cu/PI and AuNPs-NiFe/Cu/PI catalysts were evaluated for potential use in a direct NaBH₄-H₂O₂ fuel cell. The NiFe coating modified with AuNPs demonstrated significantly higher electrocatalytic activity towards the oxidation of sodium borohydride as compared to bare Au or unmodified NiFe/Cu/PI. Furthermore, it exhibited a superior power density of 89.7 mW cm⁻² at room temperature and operational stability under alkaline conditions, while the NiFe anode exhibited 73.1 mW cm⁻². These results suggest that the AuNPs-modified NiFe coating has great potential as a material for use in direct borohydride fuel cells (DBFCs) applications involving the oxidation of sodium borohydride. Full article

Planar heaters are designed to deliver uniform heat across broad surfaces and serve as critical components in applications requiring energy efficiency, safety, and mechanical flexibility, such as wearable electronics and smart textiles. However, conventional metal-based heaters are limited by poor adaptability to curved or complex surfaces, low mechanical compliance, and susceptibility to oxidation-induced degradation. To overcome these challenges, we applied a protein-assisted electroless copper (Cu) plating strategy to electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofiber substrates to fabricate flexible, conductive planar heating membranes. For interfacial functionalization, a protein-based engineering approach using bovine serum albumin (BSA) was employed to facilitate palladium ion coordination and seed formation. The resulting membrane exhibited a dense, continuous Cu coating, low sheet resistance, excellent durability under mechanical deformation, and stable heating performance at low voltages. These results demonstrate that the BSA-assisted strategy can be effectively extended to complex three-dimensional fibrous membranes, supporting its scalability and practical potential for next-generation conformal and wearable planar heaters. Full article

Direct-writing submicron copper circuits on glass with laser precision—without lithography, vacuum deposition, or etching—represents a transformative step in next-generation microfabrication. We present a high-resolution, maskless method for metallizing glass using ultrashort pulse Bessel beam laser processing, followed by silver ion activation and electroless copper plating. The laser-modified glass surface hosts nanoscale chemical defects that promote the in situ reduction of Ag⁺ to metallic Ag⁰ upon exposure to AgNO₃ solution. These silver seeds act as robust catalytic and adhesion sites for subsequent copper growth. Using this approach, we demonstrate circuit traces as narrow as 0.7 µm, featuring excellent uniformity and adhesion. Compared to conventional redistribution-layer (RDL) and under-bump-metallization (UBM) techniques, this process eliminates multiple lithographic and vacuum-based steps, significantly reducing process complexity and production time. The method is scalable and adaptable for applications in transparent electronics, fan-out packaging, and high-density interconnects. Full article

Hydrogen production via water splitting is one of the latest low-cost green hydrogen production technologies. The challenge is to develop inexpensive and highly active catalysts. Herein, we present the preparation of electrocatalysts based on cobalt–phosphorus (Co-P) coatings with different P contents for hydrogen and oxygen evolution reactions (HER and OER). The Co-P coatings were deposited on the copper (Cu) surface using the economical and simple method of electroless metal deposition. The morphology, structure, and composition of the Co-P coatings deposited on the Cu surface were studied via scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), while their activity for HER and OER in 1 M KOH was investigated using linear sweep voltammetry (LSV) and chrono-techniques. It was found that the catalyst activity for both HER and OER depends on the P content of the catalyst and varies based on the highest efficiency for each reaction. The Co-P coating with 11 wt% P exhibited the lowest overpotential value of 98.9 mV for the HER to obtain a current density of 10 mA cm⁻² compared to the Co-P coatings with 8, 5, 1.6, and 0.4 wt% P (107.6, 165.9, 218.2, and 253.9 mV, respectively). In contrast, the lowest OER overpotential (378 mV) was observed for the Co-P coating with 8 wt% P to obtain a current density of 10 mA cm⁻² as compared to the Co-P coatings with 5, 11, 1.6, and 0.4 wt% P (400, 413, 434, and 434 mV, respectively). These results suggest that the obtained catalysts are suitable for HER and OER in alkaline media. Full article

The electrolysis of water is one of low-cost green hydrogen production technologies. The main challenge regarding this technology is designing and developing low-cost and high-activity catalysts. Herein, we present a strategy to fabricate flexible electrocatalysts based on nickel–iron (NiFe) alloy coatings. NiFe coatings were plated on the flexible copper-coated polyimide surface (Cu/PI) using the low-cost and straightforward electroless metal-plating method, with morpholine borane as a reducing agent. It was found that Ni₉₀Fe₁₀, Ni₈₀Fe₂₀, Ni₆₀Fe₄₀, and Ni₃₀Fe₇₀ coatings were deposited on the Cu/PI surface; then, the concentration of Fe²⁺ in the plating solution was 0.5, 1, 5, and 10 mM, respectively. The morphology, structure, and composition of Ni_xFe_y/Cu/PI catalysts have been examined using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and inductively coupled plasma–optical emission spectroscopy (ICP-OES), whereas their activity has been investigated for hydrogen evolution (HER) and oxygen evolution (OER) reactions in 1 M KOH using linear sweep voltammetry (LSVs). It was found that the Ni₈₀Fe₂₀/Cu/PI catalyst exhibited the lowest overpotential value of −202.7 mV for the HER, obtaining a current density of 10 mA cm⁻² compared to Ni₉₀Fe₁₀/Cu/PI (−211.9 mV), Ni₆₀Fe₄₀/Cu/PI (−276.3 mV), Ni₃₀Fe₇₀/Cu/PI (−278.4 mV), and Ni (−303.4 mV). On the other hand, the lowest OER overpotential (344.7 mV) was observed for the Ni₆₀Fe₄₀/Cu/PI catalyst, obtaining a current density of 10 mA cm⁻² compared to the Ni₃₅Fe₆₅ (369.9 mV), Ni₈₀Fe₂₀ (450.2 mV), and Ni₉₀Fe₁₀ (454.2 mV) coatings, and Ni (532.1 mV). The developed Ni₆₀Fe₄₀/Cu/PI catalyst exhibit a cell potential of 1.85 V at 10 mA cm⁻². The obtained catalysts seem to be suitable flexible catalysts for HER and OER in alkaline media. Full article

Filtration membranes coated in metals such as copper have dramatically improved biofouling resistance and pathogen destruction. However, existing coating methods on polymer membranes impair membrane performance, lack uniformity, and may detach from their substrate, thus contaminating the permeate. To solve these challenges, we developed the first electroless deposition protocol to immobilize copper nanoparticles on electrospun polyacrylonitrile (PAN) fibers for the design of antimicrobial membranes. The deposition was facilitated by prior silver seeding. Distinct mats with average fiber diameters of 232 ± 36 nm, 727 ± 148 nm and 1017 ± 80 nm were evaluated for filtration performance. Well-dispersed copper nanoparticles were conformal to the fibers, preserving the open-cell architecture of the membranes. The copper particle sizes ranged from 20 to 140 nm. Infrared spectroscopy revealed the PAN fiber mats’ relative chemical stability/resistance to the copper metallization process. In addition, the classical cyclization of the cyano functional group in PAN was observed. For model polystyrene beads with average sizes of 3 μm, Cu NP–PAN fiber mats had high water flux and separation efficiency with negligible loss of Cu NP from the fibers during flow testing. Fiber size increased flux and somewhat decreased separation efficiency, though the efficiency values were still high. Full article

The production of high-purity hydrogen from hydrogen storage materials with further direct use of generated hydrogen in fuel cells is still a relevant research field. For this purpose, nickel-molybdenum-plated copper catalysts (NiMo/Cu), comprising between 1 and 20 wt.% molybdenum, as catalytic materials for hydrogen generation, were prepared using a low-cost, straightforward electroless metal deposition method by using citrate plating baths containing Ni²⁺–Mo⁶⁺ ions as a metal source and morpholine borane as a reducing agent. The catalytic activity of the prepared NiMo/Cu catalysts toward alkaline sodium borohydride (NaBH₄) hydrolysis increased with the increase in the content of molybdenum present in the catalysts. The hydrogen generation rate of 6.48 L min⁻¹ g_cat⁻¹ was achieved by employing NiMo/Cu comprising 20 wt.% at a temperature of 343 K and a calculated activation energy of 60.49 kJ mol⁻¹ with remarkable stability, retaining 94% of its initial catalytic activity for NaBH₄ hydrolysis following the completion of the fifth cycle. The synergetic effect between nickel and molybdenum, in addition to the formation of solid-state solutions between metals, promoted the hydrogen generation reaction. Full article

Three-dimensional (3D) integration has become a leading approach in chip packaging. The interconnection density and reliability of micro-bumps in chip stacking are often threatened by high bonding temperatures. The method of building chip-to-chip interconnections by electroless deposition of metal has its distinct merit, while the interfacial defect issue, especially that related to voiding during the merging of opposite sides, remains largely unsolved. In this study, to trace the influencing factors in the voiding, the growth characteristics of the electroless all-copper interconnections were examined by carrying out deposition experiments in a microfluidic channel device. The results show that when the gap between the opposite copper bumps to be electrolessly merged is as low as 10 μm, significant voids appear at the inflow side and the top of the copper bumps because the hydrogen cannot be expelled in time. A finite-element flow model of the plating solution between the chips was established, which showed that the flow rate of the plating solution around the copper bumps was much higher than in the merging gap, causing an uneven supply of reactants. Based on these findings, we proposed two potential solutions, one is to improve the flow mode of the plating solution, and the other is to add the reaction inhibitor, 2,2′-bipyridine. Finally, the combination of these two approaches successfully achieved an improved merging quality of the copper joints. Full article

Copper metal catalyst seeds have recently triggered much research interest for the development of low-cost and high-performance metallic catalysts with industrial applications. Herein, we present metallic Cu catalyst seeds deposited by an atomic layer deposition method on polymer substrates. The atomic layer deposited Cu (ALD-Cu) can ideally substitute noble metals Ag, Au, and Pd to catalyze Cu electroless deposition. The optimized deposition temperature and growth cycles of an ALD-Cu catalyzed seed layer have been obtained to achieve a flexible printed circuit (FPC) with a high performance electroless plating deposited Cu (ELD-Cu) film. The ELD-Cu films on the ALD-Cu catalyst seeds grown display a uniform and dense deposition with a low resistivity of 1.74 μΩ·cm, even in the through via and trench of substates. Furthermore, the ALD-Cu-catalyzed ELD-Cu circuits and LED devices fabricated on treated PI also demonstrate excellent conductive and mechanical features. The remarkable conductive and mechanical characteristics of the ALD-Cu seed catalyzed ELD-Cu process demonstrate its tremendous potential in high-density integrated FPC applications. Full article

Lattice structures are a group of cellular materials composed of regular repeating unit cells. Due to their extraordinary mechanical properties, such as specific mechanical strength, ultra-low density, negative Poisson’s ratio, etc., lattice structures have been widely applied in the fields of aviation and aerospace, medical devices, architecture, and automobiles. Hybrid additive manufacturing (HAM), an integrated manufacturing technology of 3D printing processes and other complementary processes, is becoming a competent candidate for conveniently delivering lattice structures with multifunctionalities, not just mechanical aspects. This work proposes a HAM technology that combines vat photopolymerization (VPP) and electroless plating process to fabricate smart metal-coated lattice structures. VPP 3D printing process is applied to create a highly precise polymer lattice structure, and thereafter electroless plating is conducted to deposit a thin layer of metal, which could be used as a resistive sensor for monitoring the mechanical loading on the structure. Ni-P layer and copper layer were successfully obtained with the resistivity of $8.2\times {10}^{-7}\mathsf{\Omega }\cdot \mathrm{m}$ and $2.0 \times {10}^{-8} \mathsf{\Omega }\cdot \mathrm{m}$, respectively. Smart lattice structures with force-loading self-sensing functionality are fabricated to prove the feasibility of this HAM technology for fabricating multifunctional polymer-metal lattice composites. Full article

With increasing interest in the rapid development of lattice structures, hybrid additive manufacturing (HAM) technology has become a competent alternative to traditional solutions such as water jet cutting and investment casting. Herein, a HAM technology that combines vat photopolymerization (VPP) and electroless/electroplating processes is developed for the fabrication of multifunctional polymer-metal lattice composites. A VPP 3D printing process is used to deliver complex lattice frameworks, and afterward, electroless plating is employed to deposit a thin layer of nickel-phosphorus (Ni-P) conductive seed layer. With the subsequent electroplating process, the thickness of the copper layer can reach 40 μm within 1 h and the resistivity is around $1.9\times {10}^{-8} \mathsf{\Omega }\cdot \mathrm{m}$, which is quite close to pure copper ($1.7 \times {10}^{-8} \mathsf{\Omega }\cdot \mathrm{m}$). The thick metal shell can largely enhance the mechanical performance of lattice structures, including structural strength, ductility, and stiffness, and meanwhile provide current supply capability for electrical applications. With this technology, the frame arms of unmanned aerial vehicles (UAV) are developed to demonstrate the application potential of this HAM technology for fabricating multifunctional polymer-metal lattice composites. Full article