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SU-8 photoresist is an ideal thermal-imprinting polymer, which has been widely used in micro-nano devices in recent years. However, the research on the filling behavior of SU-8 photoresist during thermal nanoimprinting is not complete. In this paper, the stress relaxation curves and shear stress/rate flow curves were measured to analyze the temperature dependent rheological properties of SU-8 photoresist. The filling behavior of SU-8 photoresist was discussed based on thermal imprinting results at various temperatures. High-precision nanochannels were fabricated with replication error of 2.8% at optimized thermal imprinting temperature of 85[degrees]C and duration of 10 min, which paves the way for high-precision fabrication of SU-8-based micro-nanofluidic chips. KEYWORDS nanotechnology, processing, structure, thermoplastics, viscoelastic properties, viscosity, 1 | INTRODUCTION In recent years, studies on nanofluid system have been reported in fields of DNA detection, [1-5] bio-chemical analysis, [6-8] and medicine. [9-11] Nanochannels are the basic to [...]

Nuclear factor Y (NF-Y) transcription factors play an essential role in regulating plant growth, development, and stress responses. Despite extensive research on the NF-Y gene family across various species, the knowledge regarding the NF-Y family in Ginkgo biloba remains unknown. In this study, we identified a total of 25 NF-Y genes (seven GbNF-YAs, 12 GbNF-YBs, and six GbNF-YCs) in the G. biloba genome. We characterized the gene structure, conserved motifs, multiple sequence alignments, and phylogenetic relationships with other species (Populus and Arabidopsis). Additionally, we conducted a synteny analysis, which revealed the occurrence of segment duplicated NF-YAs and NF-YBs. The promoters of GbNF-Y genes contained cis-acting elements related to stress response, and miRNA–mRNA analysis showed that some GbNF-YAs with stress-related cis-elements could be targeted by the conserved miRNA169. The expression of GbNF-YA genes responded to drought, salt, and heat treatments, with GbNF-YA6 showing significant upregulation under heat and drought stress. Subcellular localization indicated that GbNF-YA6 was located in both the nucleus and the membrane. Overexpressing GbNF-YA6 in ginkgo callus significantly induced the expression of heat-shock factors (GbHSFs), and overexpressing GbNF-YA6 in transgenic Arabidopsis enhanced its heat tolerance. Additionally, Y2H assays demonstrated that GbNF-YA6 could interact with GbHSP at the protein level. Overall, our findings offer novel insights into the role of GbNF-YA in enhancing abiotic stress tolerance and warrant further functional research of GbNF-Y genes. [ABSTRACT FROM AUTHOR]

Electrohydrodynamic jet (E-jet) printing promises to become a highly efficient and cost-effective high-resolution additive nanomanufacturing technology. However, nanoscale printing of small-molecule solvent inks requires the fabrication of nano nozzles that will accommodate the considerable spreading of the printed droplets. This study documents our steps in developing a fabrication process for nanoscale printing nozzles. First, a silicon nano nozzle mold was fabricated by side-etch lift-off, ultraviolet lithography, and deep reactive ion etching. Then, the nanoscale polymer nozzle was produced by double-casting polydimethylsiloxane and a bonding process. In the application of a polymer nano nozzle for E-jet printing of ethanolic solutions of 1-hexadecanethiol, droplets with a diameter as small as 160 nm were obtained. These results indicate that a polymer nano nozzle can be well adapted to E-jet printing with a fine resolution. [ABSTRACT FROM AUTHOR]

Hot embossing is an emerging technology, which enables cost-effective and high-productivity nanofabrication. It is important to optimize the processing parameters to achieve high replication accuracy nanostructure fabrication. In this article, to reveal the interrelationship between the hot embossing conditions and replication accuracy of two-dimensional (2D) polyethylene terephthalate (PET) nanochannels, the numerical simulations were conducted by using the generalized Maxwell model. The constants of the generalized Maxwell model were calculated by a newly established fitting formula based on experimental compressive creep curves rather than tensile stress relaxation curves. Replication accuracy of 2D PET nanochannels was evaluated by a method based on weighted averages. Orthogonal method was employed during numerical simulations to optimize the hot embossing process. Under optimized hot embossing parameters, 2D PET nanochannels, ~80 nm wide, 250 nm deep and 4 mm long, were precision-imprinted into a PET sheet, INTRODUCTION In recent years, the study of nanofluidic systems has been reported in a wide spectrum of fields such as chemistry, biology, and medicine. The fabrication technique for nanosized components [...]

Nano-imprint technology is a method of nano-pattern reproduction, has the characteristics of high resolution, high throughput, and low-cost. It can reduce the complexity and cost of the equipment while improving the resolution, which considered a promising industrial production technology. The key to nanoimprinting lies in the mold, and the quality of the mold directly determines the quality of the imprinted graphics. Here, a method for fabricating sub-100 nm concave 2D silicon nano-mold by side etch lift-off is proposed. The effects of different wet etching time and the metal deposition angle on the width of nanochannels were studied. The measurement result of dry etching shows that on the entire 4 inch silicon wafer, the width of the nanochannel varies by 4% and the depth by 2%. The width of the nanochannel between chips varies by 0.7%, and the depth variation is 1%. With this new method, high-precision and large-scale silicon nano-mold can be produced, which has great potential for realizing high-precision and low-cost manufacturing of nano devices. [ABSTRACT FROM AUTHOR]

Nano-fluidic devices have great potential in the applications of biology, chemistry, and medicine. However, their applications have been hampered by their expensive or complicated fabrication methods. We present a new and simple approach to fabricate low-cost two-dimensional (2D) nano-mold based on ultraviolet (UV) lithography and wet etching. The influence of UV lithography parameters on the width dimension of AZ5214 photoresist was investigated. With the optimized parameters of UV lithography, the width dimension of photoresist patterns had sharply decreased from microscale to nano-scale. At the same time, the influences of etching time on the over-etching amount of SiO2 film and nano-mold depth were also analyzed for further reducing the width of nano-mold. In addition, the effect of photoresist mesas deformation on the nano-mold fabrication was also studied for improving the quality of nano-mold. By the proposed method, trapezoid cross-sectional 2D nano-mold with different dimensions can be obtained for supporting varied applications. The minimum nano-mold arrays we fabricated are the ones with the dimensions of 115 nm in top edge, 284 nm in bottom edge, and 136 nm in depth. This method provides a low-cost way to fabricate high-quality and high-throughput 2D nano-mold. [ABSTRACT FROM AUTHOR]

Nanofluidic devices with two-dimensional nanochannels have many applications in biology and chemistry, however, it is still a challenge to develop a low-cost and simple method for fabricating nano-masks that can be used to produce two-dimensional nanochannels. In this paper, a novel low-cost and simple method, based on UV lithography and oxygen plasma, was proposed to fabricate nano-mask. The influence of exposure time on the photoresist mesas was investigated in the ultraviolet lithography process. The parameters of RF power and treatment time on the width reduction of photoresist mesas were analyzed by the oxygen plasma. In our work, in order to increase the efficiency controllability of photoresist removal, a RF power of 90 W, a pressure of oxygen plasma 60 Pa, and the time division method were adopted to remove photoresist by oxygen plasma. Finally, nano-patterns of photoresist mesas with bottom width of 330 nm were successfully fabricated. The proposed method provides a low-cost way to produce high-throughput two-dimensional nanochannels. [ABSTRACT FROM AUTHOR]

Polymethyl Methacrylate (PMMA) nanochannels are becoming increasingly important for biological, optical and electronic applications. To form a complete PMMA nanochannel/device, the open nanotrench will always be thermal bonded. However, the bonding process which influences the final fabrication precision of PMMA devices has not yet been studied systematically by numerical simulation. In this work, an elastic–plastic model was used for PMMA nanochannel bonding. The influence of temperature, pressure, aspect ratio, and friction coefficient on the dimension loss and max stress was studied systematically. By numerical simulation, all the main influence factors were optimized. It is expected that the proposed simulation method has a high potential for the polymer bonding process analysis. [ABSTRACT FROM AUTHOR]

The lithography contact/proximity printing technique is widely used in the fabrication of microelectronic components, optical devices, and micro-fluidic chips. However, the fabrication of nano-sized structures requires high-cost equipment. This paper proposes a low-cost method to manufacture nanostructures by ultraviolet proximity exposing lithography through a microphotomask on a conventional lithographic aligner. The influence of exposure distance on photoresist pattern size is studied, and the standing wave effect on the photoresist layer is reduced by post-baking. This cost effective method can be widely applied to fabricate patterns with a nanofeature size. [ABSTRACT FROM AUTHOR]

SU-8 is becoming increasingly important for fabrication of lab-on-a-chip devices due to its excellent chemical stability, mechanical, and optical properties. To form a complete SU-8 device, O2 plasma-assisted thermal bonding has been used to bond SU-8 layers. O2 plasma treatment is critical and has a significant influence on the fabrication quality of SU-8 devices. However, to the best of our knowledge, there is no work which analyzed O2 plasma treating process for SU-8 material in depth and systematically. In this study, the influence of O2 plasma treatment on the water contact angle and bonding strength for both un-crosslinked and crosslinked SU-8 layer was investigated in detail. The etching effect of SU-8 layer was also studied. The leakage test demonstrated that there is no gas leakage in the bonded SU-8 layer up to 0.65 Mpa which indicates the practicability of the proposed SU-8 bonding method. [ABSTRACT FROM AUTHOR]

Pb1.2−1.5xPrxZr0.52Ti0.48O3 (PPZT, x = 0%, 1%, 2%, 3%, 4%, 5%) thin films were prepared by sol–gel method on Pt(111)/Ti/SiO2/Si(100) substrates to investigate the effects of Pr doping on the crystalline structure, microstructure, dielectric properties, ferroelectric properties, and fatigue properties of PPZT thin films. X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses showed that all the samples have completely perovskite structure with (100) preferred orientation. The maximum dielectric constant and remnant polarization were obtained in 2% Pr-doped film. The results of fatigue test revealed that the fatigue properties of PPZT films doped with Pr concentrations of 1% and 2% were significantly improved. [ABSTRACT FROM AUTHOR]

Electro hydrodynamic (EHD) printing is a promising technique for alternative fabrication of high resolution micro- and nano-structures without employment of any molds or photo-masks. However, a major problem, nozzle clogging, often occurs when the viscosity of the inks or the size of ink particles is raised. We proposed in this work an economic and concise method to solve the nozzle clogging issue. A PDMS-glass disassembled nozzle was designed and fabricated, which can be bonded under pressure and separated after pressure release. The influence of substrate material, bonding pressure, aspect ratio and channel-size on the dimension loss of PDMS micro-channel was investigated by an established simulation method. It is expected that the proposed method has great potential for fabrication of reusable nozzle without the clogging problem. [ABSTRACT FROM AUTHOR]

A novel conical nozzle fabrication method for piezoelectric inkjet printhead is proposed based on the microelectromechanical system technology. By optimizing the exposure gap, exposure dose, postexposure bake (PEB), and development time, the SU-8 conical nozzle was fabricated. After thermal bonding with an open chamber, the piezoelectric inkjet printhead chamber was formed. The results show that the optimum SU-8 conical nozzle can be fabricated by applying exposure dose of 105 mJ/cm2, exposure gap of 50 µm, PEB temperature of 65°C, PEB time of 10 min, and development time of 210 s. The final size of optimum conical nozzle is the large aperture of 30.46 ± 1.17 µm, small aperture of 20.34 ± 1.42 µm, and nozzle height of 45.38 ± 1.02 µm. [ABSTRACT FROM AUTHOR]

Lead zirconate titanate (PZT) thin films deposited on Pt electrode and Pb1+x(Zr0.52,Ti0.48)O3(x = 0.10, 0.15, 0.25, 0.30) buffer layer have been prepared by sol-gel methods to investigate the effects of lead content in the buffer layer on crystalline orientation, electric and fatigue properties of PZT films. XRD and SEM showed that all films exhibited dense perovskite structure with (100) preferential orientation. The maximum dielectric constant (1571 at 100 Hz) was obtained in the PZT film with buffer layer containing 25% excess lead, which increased by 42.5% compared with the film without buffer layer. Fatigue resistance was improved by introducing buffer layer. [ABSTRACT FROM AUTHOR]