- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Synthesis of low surface-energy polyepichlorohydrin triazoles thin film
摘要： In this investigation, a new polymer with low surface energy was synthesized by grafting a triazole group onto polyepichlorohydrin (PECH) rubber that contained no halogens. The chlorine on PECH was first replaced by an azide group, and this attached azide was then converted to a triazole group with alkyl chains using the azide-alkyne Huisgen cycloaddition reaction. Analyses confirmed the structure of final product, PECH-triazole polymer. The grafting reactions increased the surface roughness. The static contact angles of water or CH2I2 droplets on the PECH-azole film were 101.7° and 71.3°, respectively. The advancing and receding contact angles for water on PECH-azide were 119.8° and 13.7°, respectively. The PECH-triazole polymer has omniphobic properties with rose petal characteristics. The PECH-triazole has low dispersive surface energy (21 mN/m) and negligible non-dispersive surface energy, giving a wetting envelope that is similar to the one of PTFE polymer. X-ray photoelectron spectroscopy and transmission infrared spectroscopy suggested that the interactions of the N atoms on the triazole ring and the O atoms on the PECH backbone constrained the orientation of CH2 groups and reduced the surface energy of the thin film.
关键词： Azide-alkyne Huisgen cycloaddition,Polyepichlorohydrin,Low surface free energy,High water adhesion,Triazole
更新于2025-09-23 15:22:29
-
Surface modification of polyamide 12 angioplasty balloons by photochemical reaction with an aromatic azide
摘要： Polyamide 12 (PA12) is used in a variety of applications when low moisture absorption, good dimensional stability, and toughness are required. Polyamide 12 is one of the polymers most frequently employed to fabricate angioplasty balloon catheters; however, its high hydrophobicity and chemical inertness require the application of coatings to make its surface more hydrophilic and biocompatible. In this work, an alternative method, based on the photochemical reaction of PA12 with a hydrophilic aromatic azide, was developed. Static and dynamic contact angle measurements evidenced that the surface modification process was able to improve PA12 wettability and that the effects were retained even after 12 months from surface treatment. Polyamide 12 modification resulted in an increase of its surface free energy, as evaluated by the van Oss, Good, and Chaudhury method. X‐ray photoelectron spectroscopy confirmed the presence of the aromatic azide on PA12 surface. Finally, compliance tests showed that the modification process did not reduce the mechanical performance of balloons.
关键词： contact angle,polyamide 12,angioplasty balloon catheter,surface free energy,surface modification
更新于2025-09-23 15:19:57
-
Surface Properties of Beech Wood after CO2 Laser Engraving
摘要： The paper deals with the properties of a beech wood surface treated by CO2 laser engraving. The studied concerns were the discoloration, changes to morphology assessed through roughness and waviness parameters, and surface wetting with standard liquids (water and diiodomethane), with the aim of determining the wood surface free energy. The results have confirmed that the studied properties of the beech wood surface varied significantly, which were affected by the laser beam power P and raster density n. With increasing P and n, the lightness L* (expressed in CIE L*a*b* color space) decreased significantly. We also observed significant variation in the color coordinates a* and b*. At 8% laser power, the roughness and waviness parameters measured parallel as well as perpendicular to the grain increased proportionally with the increasing raster density. However, 4% laser power was not associated with distinct changes. Increasing the raster density reduced beech wood surface wetting equally with water and with diiodomethane. This was reflected in the higher contact angle values. The wood surface exhibited higher hydrophobicity at 4% laser power. At this power, the increasing raster density was reflected in the decreasing surface free energy, due to its polar component decrease. At 8% laser power, the changes in surface free energy were very minor from the practical viewpoint. The results suggest a potential good adhesion between film-forming materials and wood. However, the gluing performance may be negatively affected by the high roughness attained at 8% laser power and at higher raster densities.
关键词： color,wetting,surface properties,CO2 laser,roughness,contact angle,beech wood,surface free energy
更新于2025-09-19 17:13:59
-
Nonlinear torsional buckling and postbuckling analysis of cylindrical silicon nanoshells incorporating surface free energy effects
摘要： In the present study, a size-dependent shell model is developed which can afford to describe the nonlinear torsional buckling and postbuckling characteristics of cylindrical nanoshells in the presence of surface stress effects. To accomplish this purpose, the Gurtin–Murdoch theory of elasticity together with the von Karman geometric nonlinearity is implemented into the ?rst-order shear deformation shell theory. A linear variation through the thickness is considered for the normal stress component of the bulk to satisfy the balance conditions on the free surfaces of the nanoshell. By means of the virtual work principle, the non-classical governing differential equations are constructed in which the transverse displacement and Airy stress function are considered as independent variables. Thereafter, a boundary layer theory is employed including the effect of surface stress in conjunction with the nonlinear prebuckling deformations and the large postbuckling de?ections. Subsequently, an ef?cient solution methodology based on an improved perturbation technique is put to use to obtain the size-dependent critical torsional buckling loads and the associated postbuckling equilibrium paths. It is observed that the torsional load exhibits a signi?cant increase after reaching the minimum postbuckling load. Also, it is revealed that the effect of surface stress becomes negligible at high values of the de?ection.
关键词： First-order shear deformation shell theory,Nonlinear torsional buckling,Postbuckling analysis,Surface free energy effects,Cylindrical silicon nanoshells,Gurtin–Murdoch theory,von Karman geometric nonlinearity
更新于2025-09-10 09:29:36
-
[IEEE 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Austin, TX, USA (2018.9.24-2018.9.26)] 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Topography Simulation of 4H-SiC-Chemical-Vapor-Deposition Trench Filling Including an OrientationDependent Surface Free Energy
摘要： Topography simulation of chemical-vapor-deposition (CVD) trench filling has been advanced as a tool for designing fabrication processes of high-voltage 4H-SiC superjunction devices. In the longitudinal section of filled stripe trenches, an experimentally observed dip, which had not been well reproduced with a previous technique using a fixed surface free energy (γ), came to be qualitatively reproduced by including an orientation dependence of γ.
关键词： orientation,SiC,surface free energy,CVD,trench
更新于2025-09-04 15:30:14