RESUMEN
Facing the rapid development of 6G communication, long-wave infrared metasurface and biomimetic microfluidics, the performance requirements for microsystems based on metal tiny structures are gradually increasing. As one of powerful methods for fabrication metal complex microstructures, localized electrochemical deposition microadditive manufacturing technology can fabricate copper metal micro overhanging structures without masks and supporting materials. In this study, the role of the microprobe cantilever (MC) in localized electrodeposition was studied. The MC can be used for precise deposition with electrolyte localized transport function and high accuracy force-displacement sensitivity. To prove this, the electrolyte flow was simulated when the MC was in bending or normal state. The simulation results can indicate the influence of turbulent flow on the electrolyte flow velocity and the pressure at the end of the pyramid. The results show that the internal flow velocity increased by 8.9% in the bending probe as compared with normal. Besides, this study analyzed the force-potential sensitivity characteristics of the MC. Using the deformation of the MC as an intermediate variable, the model of the probe tip displacement caused by the growth of the deposit and the voltage value displayed by the photodetector was mathematically established. In addition, the deposition of a single voxel was simulated by simulation process with the simulated height of 520 nm for one voxel, and the coincidence of simulation and experimental results was 93.1%. In conclusion, this method provides a new way for localized electrodeposition of complex microstructures.
RESUMEN
With the increasing problem of water pollution, oil-water separation technology has attracted widespread attention worldwide. In this study, we proposed laser electrochemical deposition hybrid preparation of an oil-water separation mesh and introduced a back-propagation (BP) neural network model to realize the regulation of metal filter mesh. Among them, the coating coverage and electrochemical deposition quality were improved by laser electrochemical deposition composite processing. Based on the BP neural network model, the pore size after electrochemical deposition could be obtained only by inputting the processing parameters into the model, enabling the prediction and control of the pore size of the processed stainless-steel mesh (SSM), and the maximum residual difference between the predicted value and the experimental value was 1.5%. According to the oil-water separation theory and practical requirements, the corresponding electrochemical deposition potential and electrochemical deposition time were determined by the BP neural network model, which reduced the cost and time loss. In addition, the prepared SSM was found to achieve efficient separation of oil and water mixtures, reaching 99.9% separation efficiency in a combination with oil-water separation, along with other performance tests without chemical modification. The prepared SSM showed good mechanical durability and the separation efficiency exceeded 95% after sandpaper abrasion, thus, still maintaining the separation ability of oil-water mixture. Compared to other similar preparation methods, the method proposed in this study has the advantages of controllable pore size, simplicity, convenience, environmental friendliness, and durable wear resistance, offering important application potential in the treatment of oily wastewater.
RESUMEN
In this study, a simple method without any additional chemical modification is proposed to fabricate underoil superhydrophobic surfaces with micro- and nano-hierarchical structures using a nanosecond laser system. The fabricated surfaces exhibited extreme superhydrophobicity and underoil superhydrophobicity with high contact angles of 153.8 ± 1.5° and 161.3 ± 1.1°, respectively. The results show that even after 20 abrasion cycles, the fabricated surfaces retained water repellency and self-cleaning performance under oil, while the superhydrophobicity in air was not resistant to wear. In addition, the fabricated brass meshes can also be used to separate oil in an oil-water mixture based on the prewetting induced underoil superhydrophobicity after being damaged. The separation efficiency was as high as 97.8%, which made them more appropriate for the oil-water separation than those based on superhydrophobicity. The proposed fabrication method is suitable for large-scale and mass production and provides a new avenue and possibility for further development of robust functional interface materials.
RESUMEN
In this work, the localized electrochemical micro additive manufacturing technology based on the FluidFM (fluidic force microscope) has been introduced to fabricate micro three-dimensional overhang metal structures at sub-micron resolution. It breaks through the localized deposition previously achieved by micro-anode precision movement, and the micro-injection of the electrolyte is achieved in a stable electric field distribution. The structure of electrochemical facilities has been designed and optimized. More importantly, the local electrochemical deposition process has been analyzed with positive source diffusion, and the mathematical modeling has been revealed in the particle conversion process. A mathematical model is proposed for the species flux under the action of pulsed pressure in an innovatively localized liquid feeding process. Besides, the linear structure, bulk structure, complex structure, and large-area structure of the additive manufacturing are analyzed separately. The experimental diameter of the deposited cylinder structure is linearly fitted. The aspect ratio of the structure is greater than 20, the surface roughness value is between 0.1-0.2 µm at the surface of bulk structures, and the abilities are verified for deposition of overhang, hollow complex structures. Moreover, this work verifies the feasibility of 3D overhang array submicron structure additive manufacturing, with the application of pulsed pressure. Furthermore, this technology opens new avenues for the direct fabrication of nano circuit interconnection, tiny sensors, and micro antennas.
RESUMEN
In this work, the bioinspired reversible switch between underwater superoleophobicity/superaerophobicity and oleophilicity/aerophilicity and improved antireflective property were successfully demonstrated on the nanosecond laser-structured titanium surfaces. Titanium materials were first transformed to be superhydrophobic after nanosecond laser ablation and low-temperature annealing treatments, showing oleophilicity/aerophilicity in water. If the surfaces were prewetted with absolute ethanol and then immersed into water, the surfaces showed superoleophobicity/superaerophobicity. More importantly, the underwater oleophilicity/aerophilicity of the surfaces could be easily recovered by natural drying, and the switch between the underwater superoleophobicity/superaerophobicity and oleophilicity/aerophilicity could be repeated many cycles. Moreover, based on the original antireflective performance of the surface of the laser-ablated micro/nanoscale structures, we demonstrated that the inspired improved antireflective property could be skillfully realized by the prewetting treatment. The developed bioinspired multifunctional materials provide a versatile platform for the potential applications, such as controlling oil droplets, bubbles, and optical behavior.
RESUMEN
Reducing the contact time of a water droplet on non-wetting surfaces has great potential in the areas of self-cleaning and anti-icing, and gradually develops into a hot issue in the field of wettability surfaces. However, the existing literature on dynamic behavior of water drops impacting on superhydrophobic surfaces with various structural shapes is insufficient. Inspired by the microstructure of lotus leaf and rice leaf, dual-level and three-level structures on plane and convex surfaces were successfully fabricated by wire electrical discharge machining on aluminum alloy. After spraying hydrophobic nanoparticles on the surfaces, the plane and convex surfaces with dual-level and three-level structures showed good superhydrophobic property. Bouncing dynamics of impact droplets on the superhydrophobic surfaces wereinvestigated, and the results indicated that the contact time of plane superhydrophobic surface with a three-level structure was minimal, which is 60.4% less than the plane superhydrophobic surface with dual-level structure. The effect of the interval S, width D, and height H of the structure on the plane superhydrophobic surface with three-level structure on contact time was evaluated to obtain the best structural parameters for reducing contact time. This research is believed to guide the direction of the structural design of the droplet impinging on solid surfaces.