Lithography-induced hydrophobic surfaces of silicon wafers with excellent anisotropic wetting properties

In recent years, hydrophobic surfaces have attracted more and more attentions from many researchers. In this paper, we comprehensively discussed the effects of specific parameters of microstructures on the wetting properties by using the theoretical models, the effects of microstructures on two-dimensional anisotropic properties and the water droplet impact experiment. Firstly, the relationships between the CAs and variable parameters were explored after the formula derivation for three various patterns. Then three different patterns were fabricated successfully on the silicon wafers by lithography technology and the effects of microstructures (including LWD parameters and interval parameters) on surface wettability were studied based on the theoretical research. After that, the effects of microstructures on two-dimensional anisotropic properties were also studied. Finally, the water droplet impact experiment was carried out and the viscoelastic properties were simply investigated. Our research proposed a potential method for fabricating hydrophobic surfaces with excellent anisotropic properties. This method may be widely used in a variety of academic and industrial applications in the future

Torsional properties of Boron Nitride nanocones with different cone heights, disclination angles and simulation temperatures

The torsional properties of single-walled boron nitride (BN) nanocones at different cone heights, disclination angles and simulation temperatures have been investigated using molecular dynamics (MD) simulation. The simulation results indicate that the torque and average potential energy decrease with the increasing cone height and disclination angle, and the failure torsion angle increases with the increasing cone height and disclination angle. For different simulation temperatures, the torsional behavior of BN nanocones at higher simulation temperature is more serious and earlier to reach a failure point, the maximum torque and average potential energy of the system decrease with the increasing simulation temperature. For different loading rates, the failure torsion angle decreases with the increasing loading rate, so the fracture of BN nanocone occurred earlier with higher loading rate. Therefore, the cone height, disclination angle, simulation temperature and loading rate are considered to be four main influencing factors for the torsional properties of the BN nanocones

catena-Poly[[nickel(II)-μ3-1,1-dicyano­ethene-2,2-dithiol­ato-κ4 S,S′:N:N′-bis­[(15-crown-5)magnesium(II)]-μ3-1,1-dicyano­ethene-2,2-dithiol­ato-κ4 N:N′:S,S′] dichloride]

The reaction of MgCl2, NiCl2, and Na2(i-mnt) (i-mnt is 1,1-dicyano­thene-2,2-dithiol­ate) with 15-crown-5 (15-C-5) leads to an infinite chain polymer, {[NiMg2(C4N2S2)2(C10H20O5)2]Cl2}n or {[Mg(15-C-5)]2[Ni(i-mnt)2]Cl2}n, which consists of two [Mg(15-C-5)]2+ complex cations, one [Ni(i-mnt)2]2− complex anion and two Cl− ions per formula unit. In the [Ni(i-mnt)2]2− complex anion, Ni2+ is located on a crystallographic mirror plane with a slightly distorted square-planar coordination by four S atoms. In the [Mg(15-C-5)]2+ complex cations, the Mg and one O atom of the crown lie on mirror planes and the Mg atoms are in sevenfold coordination environments of five O atoms from the crown and two N atoms from two i-mnt anions. The bridging of the two complexes via the Mg—N bonds leads to the formation of one-dimensional chains along the a axis

Laser-induced changes in titanium by femtosecond, picosecond and millisecond laser ablation

In order to realize the qualitative control of the laser-induced changes trend and the quantitative control of the laser-induced changes range in titanium upon laser irradiation with different pulse duration, comparative ablation experiments by femtosecond, picosecond and millisecond pulsed lasers were carried out on titanium in this study. Then the final surface morphology, aspect ratio, chemical composition and microstructural state of the ablated titanium were analyzed by laser scanning confocal microscopy, X-ray photoelectron spectroscopy and transmission electron microscopy, respectively. The dependency of the morphology, size, composition and microstructure of ablated titanium on laser pulse duration variation were emphatically discussed. It is found that, as the laser pulse duration increases from femtosecond to millisecond scale, surface morphology quality of ablated titanium gets worse, aspect ratio of microgroove decreases, proportion of titanium oxides in final ablation products becomes larger and the microstructural state of ablated titanium has a higher amorphization degree, which can be attributed to the decreased laser intensity per pulse and enhanced heat conduction effect in titanium with the pulse duration increasing

The investigation of mechanical and thermal properties of super-hydrophobic nitinol surfaces fabricated by hybrid methods of laser irradiation and carbon ion implantation

Comparing with laser irradiation only, the laser ablation combined with chemical modification process is a widely used technique to obtain bio-inspired super-hydrophobic surface. However, the as-prepared surfaces may be polluted by toxic substance during chemical modification such as fluoroalkyl silane and stearic acid. The side effect of polluted functional surface on organisms and environment limited its application value. In this paper, a green and environmental-friendly super-hydrophobic surface was quickly fabricated on nitinol substrates through hybrid of nanosecond laser ablation and carbon ion implantation. The time that turning from super-hydrophilicity to super-hydrophobicity was only 16 hours exhibiting high efficiency compared with pure laser processing. Surface morphology and chemical component were systematically investigated to reveal the formation mechanism of super-hydrophobicity in such short time. The mechanical abrasion tests implied that the mechanical properties of surface microstructure could be heightened after carbon ion implantation, showing the superior structure stability. It is noted that chemical modified super-hydrophobicity could be hardly destroyed under high temperature, and the thermal stability of this ion implanted super-hydrophobic surface was on a par with it. This hybrid method of laser irradiation and carbon ion implantation paves a green way for rapid fabrication super-hydrophobic surface on nitinol, which would have great application value in biomedicine and industry

Case Report: Unedited allogeneic chimeric antigen receptor T cell bridging to conditioning-free hematopoietic stem cell transplantation for a child with refractory Burkitt lymphoma

PurposeBurkitt lymphoma (BL) is the most common tumor of non-Hodgkin’s lymphoma (NHL) in children, accounting for about 40% of cases. Although different combined short-course chemotherapies have achieved a good effect, refractory/relapsed BL has a poor prognosis with cure rates less than 30%. Chimeric antigen receptor T cell (CAR-T) therapy has developed rapidly in recent years and achieved excellent results in acute lymphoblastic leukemia (ALL). However, in some cases, there is a failure to produce autologous CAR-T cells because of T-cell dysfunction. In such cases, allogeneic CAR-T therapy has to be considered.MethodsA 17-year-old boy with stage II BL did not respond to extensive chemotherapy and sequential autologous CAR-T therapy. Lentiviral vectors containing anti-CD20-BB-ζ (20CAR) and anti-CD22-BB-ζ (22CAR) transgenes were used to modify the T cells from an HLA-identical matched unrelated donor. Flow cytometry was used to assess the cytokine analyses and CAR-T cell persistence in peripheral blood, enumerated by qPCR as copies per ug DNA. Informed consent for autologous/allogeneic CAR-T therapy was obtained from the patient and his legal guardian.ResultsUnedited HLA-matched allogeneic CD20 and CD22 CAR-T cells were infused after lymphodepletion chemotherapy with cyclophosphamide and fludarabine. The patient experienced Grade IV cytokine release syndrome (CRS) and went into complete remission (CR) after anti-inflammatory treatment including tocilizumab. Because of persistent pancytopenia and full donor chimerism, the same donor’s conditioning-free peripheral blood stem cells were successfully transplanted 55 days post CAR-T. Neutrophils were engrafted at day +11 and platelets were rebuilt at day +47 without obvious acute graft-versus-host disease (GVHD), but there was mild chronic GVHD in the skin and eyes. Currently, active anti-rejection therapy is still underway.ConclusionUnedited HLA-matched allogeneic CAR-T cell therapy could be an innovative, effective, and safe treatment for children with refractory/relapse BL without obvious acute GVHD. Conditioning-free allogeneic hematopoietic stem cell transplantation (HSCT) from the same donor is feasible for a patient with full donor T-cell chimerism after allogeneic CAR-T. It cannot be ignored that close GVHD monitoring is needed post HSCT

Molecular dynamics studies of ultrafast laser-induced phase and structural change in crystalline silicon

In this work, thermodynamic phenomena in crystalline silicon irradiated by an ultrafast laser pulse were studied using the method of molecular dynamics simulations. The Stillinger-Weber potential was used to model the crystalline silicon. The temperature development in silicon when heated by an ultrafast laser pulse was tracked. Melting and resolidification processes and the resulting structural change were investigated. Radial Distribution Functions were used to track the liquid-amorphous interface during resolidification. It was found that the temperature at the solid-liquid interface could deviate from the equilibrium melting temperature by several hundred degrees. After the melted layer was solidified, some melted material became crystalline and the rest of the material remained in an amorphous state. The difference in the final state was associated with the rate of resolidification and both of the qualitative and quantitative analyses of the relationship between the final atom structure and resolidification rate were made. (C) 2012 Elsevier Ltd. All rights reserved

Study on the Fabrication of Super-Hydrophobic Surface on Inconel Alloy via Nanosecond Laser Ablation

Nanosecond laser ablated metallic surfaces showed initial super-hydrophilicity, and then experienced gradual wettability conversion to super-hydrophobicity with the increase of exposing time to ambient air. Due to the presence of hierarchical structures and change of surface chemistry, the laser-induced Inconel alloy surfaces showed a stable apparent contact angle beyond 150° over 30-day air exposure. The wetting states were proposed to elucidate the initial super-hydrophilicity and the final super-hydrophobicity. The basic fundaments behind the wettability conversion was explored by analyzing surface chemistry using X-ray photoelectron spectroscopy (XPS). The results indicated that the origins of super-hydrophobicity were identified as the increase of carbon content and the dominance of C–C(H) functional group. The C–C(H) bond with excellent nonpolarity derived from the chemisorbed airborne hydrocarbons, which resulted in dramatic reduction of surface-free-energy. This study confirmed that the surface chemistry is not the only factor to determine surface super-hydrophobicity. The laser-induced super-hydrophobicity was attributed to the synergistic effect of surface topography and surface chemical compositions. In this work, the corresponding chemical reaction was particularly described to discuss how the airborne hydrocarbons were attached onto the laser ablated surfaces, which reveals the generation mechanism of air-exposed super-hydrophobic surfaces

Study on the fabrication of titanium surface texture by nanosecond laser and its wettability

Laser processing technology can produce various types of surface textures on material. In order to investigate the effect of surface texture type processed by laser on the wettability, line, grid and spot patterns are fabricated on titanium surface based on nanosecond laser processing technology. Then surface morphology, water contact angle, roughness and chemical composition of the processed titanium surface are analyzed by scanning electron microscope, contact angle measuring device, surface analyzer and X-ray photoelectron spectroscopy, respectively. It is found that the roughness of titanium surfaces processed by nanosecond laser increases significantly compared with that of the unprocessed titanium surface, while the surface contact angles of the processed titanium surfaces are all less than 90°. As time goes on, the chemical composition variation of ablated titanium surface results in the change of material surface free energy, which leads to a general increase of the surface contact angle. Finally, the surface contact angle is almost unchanged once the chemical composition of titanium surface reaches steady state. For each type of surface texture, surface contact angle increases as the roughness rises. The surface contact angles of processed titanium surfaces with line, grid and spot patterns can be 157.2°, 153.1° and 134.6°, which verifies the possibility of wettability change of titanium from hydrophilicity to hydrophobicity

Laser-induced zinc metal battery anodes with ultra-long cycling performance

Zinc ion batteries show great potential as favorable options for both portable and grid-scale applications due to their inherently high safety, low cost, and relatively high theoretical energy density. However, the flat zinc metal anodes are not capable of long cycling performance owing to severe dendrites formation during the charge-discharge process. In this study, we employed nanosecond laser to modify zinc surface morphology and surface chemistry in order to alleviate the dendrites growth. The results demonstrate that the laser-induced zinc foil (LZF) surfaces show super-hydrophilic property with microstructures and a layer of ZnO coating. The symmetric cells and half-cells investigations indicate that the LZF electrode possesses lower nucleation overpotential and stable plating/striping behavior. Moreover, excellent zinc ion battery performance is achieved with activated carbon (AC) cathode, stably working for 20000 cycles at 2 A/g and 50000 cycles at 10 A/g with the Coulombic efficiency almost 100%. This paper offers new option for laser fabrication of high-performance zinc anodes for Zn-ion batteries