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排序方式: 共有136条查询结果,搜索用时 31 毫秒
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Molecular dynamics simulations of nanoimprint lithography (NIL) were performed to investigate the effects of three critical process parameters in NIL: stamp shape, adhesive energy between the stamp and polymer film, and imprint temperature. The proposed simulation model of the NIL process consists of an amorphous SiO2 stamp with a line pattern, an amorphous poly(methylmethacrylate) film, and a Si substrate under the periodic boundary condition in the horizontal direction to simulate a real NIL process imprinting periodical line patterns. The behavior of polymer deformation and the effects of adhesion on pattern transfer were investigated by observing the deformation process, calculating the imprint and separation forces, and analyzing the density and stress distribution inside the polymer film. In addition, their dependency on the process parameters is also discussed with reference to the changes in pattern shape, adhesive energy between the stamp and polymer atoms, and imprint temperature of the polymer film. During the imprint process, the rectangular pattern shows inferior cavity filling and higher stress concentration compared to trapezoidal and triangular patterns because it requires much larger flow and deformation of the polymer film. Low imprint temperature also produces high stress concentration and large imprint force due to the lower fluidity of polymer film. In the separation process, the rectangular pattern generates the largest separation force and causes the most serious defects of the transferred pattern and even the polymer film, while the triangular pattern shows the most satisfactory pattern transfer. In addition, the adhesive energy between the stamp and the polymer film also strongly influences the adhesion between the stamp and the polymer film. Low adhesive energy reduces the separation force of the stamp and transferred pattern defects, and therefore enhances the quality of pattern transfer. 相似文献
13.
Hartmut Stöcker Maximilian Rühl Anett Heinrich Erik Mehner Dirk C. Meyer 《Journal of Electrostatics》2013,71(5):905-909
The triboelectric effect describes electrical charging when bringing different materials into contact. We report on the generation of hard X-ray radiation by peeling various adhesive tapes under medium vacuum conditions. Beside vacuum housing and pumps as instrumentation only an electric motor, two rolls and a metal foil as target material are necessary. The spectral distribution of generated X-rays was analyzed using an energy-dispersive detector. Depending on peeling speed, pressure and choice of material combination, electrons with energies sufficient to excite emission in the hard X-ray region are produced. The results are discussed in terms of triboelectric separation of charge carriers. 相似文献
14.
《Particuology》2015
An organic silane acrylate resin (PMBK) was synthesized by free-radical solution polymerization using methyl methacrylate, butyl acrylate and (3-methacryloxypropyl)trimethoxysilane as monomers. Aluminum (Al) particles were then encapsulated in inorganic–organic hybrid films that were prepared by hydrolysis and condensation of PMBK and tetraethyl orthosilicate (TEOS) on the surface of Al pigments. Characterization results showed that PMBK and TEOS could simultaneously hydrolyze and condense with hydroxyl groups on the surface of the Al particles to form composite Al particles coated with inorganic–organic hybrid films. Compared with raw Al particles, the corrosion resistance and adhesive properties of paint films containing the composite Al particles were improved greatly, while the glossiness of the paint films decreased slightly, from 48.6° to 47.0°. In alkaline media (pH 11), the volume of evolved H2 of composite Al particles was only 3.5 mL, whereas that of raw Al was 83.5 mL. The glossiness of paint films containing composite Al particles decreased by 1.66% after immersion in alkaline media for 24 h, whereas that of raw Al decreased by 14.82%. Peel-off tests of the paint films showed that the composite particles moved slightly away from the paint films. In contrast, the raw Al particles were seriously desquamated, suggesting encapsulation of hybrid films can greatly improve the adhesive properties of Al particles in paint films. 相似文献
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16.
Novel strategy in enhancing stability and corrosion resistance for hydrophobic functional films on copper surfaces 总被引:2,自引:0,他引:2
Shougang Chen Yan Chen Yanhua Lei Yansheng Yin 《Electrochemistry communications》2009,11(8):1675-1679
A rod-like 1-dodecanethiol film assisted with the preferential adhesion of polydopamine was prepared on the non-etching copper surfaces by a simple dip-coating method. The formation and surface structure of the film were characterized by water contact angle measurement, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Once the 1-dodecanethiol film formed on the polydopamine-coated copper surface, the hydrophilic surface changed to hydrophobic. The corrosion behavior of the functional films was evaluated by the electrochemical impedance spectroscopy (EIS). The excellent corrosion resistance property could be ascribed to the compact film structure and good seawater stability for modified copper surface, especially in limiting the infiltration of Cl−. 相似文献
17.
Zunxu Liu Paolo S. Valvo YongAn Huang Zhouping Yin 《International Journal of Solids and Structures》2013,50(22-23):3528-3538
The paper presents a mechanical model for predicting the cohesive failure of a periodic array of integrated circuit (IC) chips adhesively bonded to a stretched substrate. A unit cell of the layered structure consisting of the IC chips, adhesive layer, and substrate is modeled as an assembly of two elastic Timoshenko beams, representing the chip and substrate, connected by an elastic interface, representing the adhesive. Accordingly, the stresses and energy release rate (ERR) in the adhesive layer – responsible for the premature cracking of the adhesive and debonding of the IC chips – are identified with the corresponding quantities computed for the elastic interface. Expressions for the adhesive stresses and ERR are given in terms of geometrical dimensions and material properties, combined with integration constants obtained numerically via the multi-segment analysis method. For comparison, the stresses in the adhesive are also computed based on a finite element model, and the ERR is evaluated using the virtual crack-closure technique (VCCT). The analytical predictions and numerical results match fairly well, considering the effects of key factors, such as the distance between adjacent chips, the chip size, the material properties of adhesive and substrate. The interaction between the chips is shown to have relevant effects on the adhesive stresses. In particular, only the mode II contributes to the ERR which increases with the ratio of the chip size to the distance between the chips and with the compliance of the adhesive and substrate layers. 相似文献
18.
《International Journal of Solids and Structures》2014,51(3-4):566-574
At small length scales, the adhesion and surface effect are of great significance, both of which play important roles in the contact between two elastic solids. In this study, the classical Johnson–Kendall–Roberts (JKR) adhesive contact theory is generalized to the nanoscale at which the surface effect is considered. The influence of the surface stress on the JKR adhesive contact is investigated by employing the non-classical Boussinesq fundamental solutions. It is found that, compared with the classical theory, the pull-off force increases while the critical contact radius decreases as a result of the surface effect. Numerical results show that a relative error of 10% can be introduced in the pull-off force when the indenter radius is less than 20 nm. A detailed theoretical analysis of this interesting phenomenon is presented based on dimensional analysis, and two scaling laws for the adhesive contact at the nanoscale are constructed. These two new scaling laws reveal that the pull-off force is relevant to the elastic properties of the bulk materials, which is different from the classical adhesive contact theory. The present work is promising for the engineering applications in micro-electro-mechanical systems (MEMS) and nano-intelligent devices. 相似文献
19.
20.
Stretchable electronics represents a direction of recent development in next-generation semiconductor devices.Such systems have the potential to offer the performance of conventional wafer-based technologies,but they can be stretched like a rubber band,twisted like a rope, bent over a pencil,and folded like a piece of paper.Isolating the active devices from strains associated with such deformations is an important aspect of design.One strategy involves the shielding of the electronics from deformation of the substrate through insertion of a compliant adhesive layer. This paper establishes a simple,analytical model and validates the results by the finite element method.The results show that a relatively thick,compliant adhesive is effective to reduce the strain in the electronics,as is a relatively short film. 相似文献