CHEMICAL ENGINEERING SCIENCE
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2024
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IF 4.1
Qichen Shang,Daiwei Gu,Lin Sheng,Yu Chang,Jian Deng,Guangsheng Luo
Laminar jet flow is an underlying phenomenon used to generate droplets efficiently. However, its hydrodynamics at the microscale remains unknown. This work focuses on the scale effect. We innovatively propose the difference between the jet at the microscale and that at the regular scale is not in the wave development but in the regime of flow pattern, and it’s much more stable at the microscale. The characteristic effect at the microscale due to the intensified gas/liquid/solid–liquid interaction is first reported. The variations of characteristic sizes and hydrodynamics with the kinetic energy, physical property, and structural size at the microscale are analyzed by introducing two key parameters − wave velocity and wave numbers, which are first proposed. The result shows that the kinetic energy determines the hydrodynamics. Viscosity and interfacial tension significantly affect the microscale laminar jet. Using wave numbers, Tyler’s equation is modified, guiding the design of effective microdroplet-generation devices.
研究领域:
流体力学
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微流控技术
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产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2019
·
IF 4.85
Guohui Li,Kun Jiang,Sher Zaman,Jinnan Xuan,Zhiqiang Wang,Fengxia Geng
Tuning the feature sizes and surface moiety groups of a two-dimensional (2D) sheet material has been regarded as the most effective strategy for achieving desired physical and chemical properties. The newly emerging transition-metal carbide or nitride sheets, generally referred to as MXenes, are of interest to the research community owing to their versatile behavior. While the chemical stability of MXenes is of pivotal importance to their real applications, a systematic study of examining the effect of their surface and lateral size on the resulting chemical stability is still lacking. Herein, by systematically varying the synthesis parameters, we obtained both regular and ultrasmall Ti3C2 sheets with different surfaces, namely, Al oxyanions or OH/F. To investigate the chemical stability and sustainability of each Ti3C2 sheet in an oxidizing environment, including an ambient atmosphere and a H2O2 medium, the evolution of phase, morphology, and optical behavior was carefully studied. The sheets covered with Al oxyanions had greater structural stability than those covered with the other species considered in this study, which may be due to the Al oxyanions acting like a shield and passivating the surface in the oxidizing atmosphere. Regarding the effect of feature size, thinner sheets or those with smaller lateral dimensions showed improved oxidation resistance, which could be due to the difficulty encountered in the structural recrystallization from Ti3C2 to oxidized product TiO2. This study provides a deeper understanding of MXenes and a method to efficiently engineer structures with desired performances.
研究领域:
材料科学
·
化学
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产品关联
DOI
PubMed
高影响因子
ACS Nano
·
2021
·
IF 15.881
Wenfei Liu,Jiabao Wang,Xiuzhen Xu,Chuanzhen Zhao,Xiaobin Xu,Paul S. Weiss
Conventional photolithography, due to its scalability, robustness, and straightforward processes, has been widely applied to micro- and nanostructure manufacturing in electronics, optics, and biology. However, optical diffraction limits the ultimate resolution of conventional photolithography, which hinders its potential in nanoscale patterning for broader applications. Here, we introduce a derivative of conventional photolithography for nanoscale patterning called dual-layer photolithography (DLPL), which is based on the controlled exposure and development of overlapping positive and negative photoresists. In a typical experiment, substrates are sequentially coated by two layers of photoresists (both positive and negative). Then, we purposefully control the exposure time to generate slightly larger features in the positive photoresist than those in the negative photoresist. After development, their overlapping areas become the final features, which outline the original features. We demonstrate line widths down to 300 nm here, which can be readily improved with more precise control. By adjusting the lithography parameters and material deposition, the feature sizes, shapes (e.g., rings, numbers, letters), line widths (300–900 nm), and materials (e.g., SiO2, Cr, and Ag) of these features can be independently controlled. Combined with anisotropic etching, more complex three-dimensional nanostructures can be fabricated as well, as we demonstrate here with Si. We further fabricate photodetectors as an example application to show that these nanostructures fabricated by DLPL can be used to promote light-trapping MAPbI3 perovskite films to achieve good photoelectric properties. This strategy is not limited to ultraviolet photolithography and may also be incorporated into other energetic beam-based lithographic approaches, including deep and extreme ultraviolet photolithographies and electron beam lithography, to enhance their resolution.
研究领域:
纳米制造
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材料科学
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光学工程
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DOI
PubMed
高影响因子
ACS Applied Nano Materials
·
2025
·
IF 5.5
Rui Zhang,Xiao-Hua Hu,Xiuzhen Xu,Zixin Zhuo,Shisheng Xiong,Xiaobin Xu
We report a patterning technique called bilayer e-beam lithography (BEBL), which employs direct-writing electron beam lithography on a bilayer photoresist system to achieve outline-like features with line widths smaller than the original writing pattern. This method leverages the subtractive outcome of two opposite photoresist layers─one positive and one negative─following e-beam exposure and development. The critical dimension (CD) of these outline-like BEBL features can be readily adjusted by manipulating the exposure and development conditions of the photoresists. We have demonstrated both line/space and via patterns using BEBL, with the CD of line/space patterns ranging from 6 to 48 nm. Note that a CD of 6 nm is not the BEBL’s theoretical limit. Furthermore, by incorporating an additional cross-patterning step, the line/space patterns can be converted into via patterns. Besides, we demonstrated the patterning flexibility of BEBL; outlines of complex features such as symbols and numbers were fabricated. BEBL holds promising potential for broad applications in nanoelectronics and serves as a valuable tool for fundamental research in nanoscience.
研究领域:
纳米科学
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电子工程
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材料科学
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产品关联
DOI
高影响因子
Scientific Reports
·
2015
·Vol. 5
·期 1
·1-8
·
IF 5.578
Qu JieHao,Hou XianLiang,Fan WanChao,Xi GuangHui,Diao HongYan,Liu XiangDon
A facile strategy for fabricating scalable stamps has been developed using cross-linked polyacrylamide gel (PAMG) that controllably and precisely shrinks and swells with water content. Aligned patterns of natural DNA molecules were prepared by evaporative self-assembly on a PMMA substrate and were transferred to unsaturated polyester resin (UPR) to form a negative replica. The negative was used to pattern the linear structures onto the surface of water-swollen PAMG and the pattern sizes on the PAMG stamp were customized by adjusting the water content of the PAMG. As a result, consistent reproduction of DNA patterns could be achieved with feature sizes that can be controlled over the range of 40%–200% of the original pattern dimensions. This methodology is novel and may pave a new avenue for manufacturing stamp-based functional nanostructures in a simple and cost-effective manner on a large scale.
研究领域:
纳米技术
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材料科学
·
生物工程
✓ 已验证
DOI
PubMed
高影响因子
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