共查询到20条相似文献,搜索用时 764 毫秒
1.
《Vacuum》2013
In this work, surface properties of polyimide (PI) films coated by thin layers deposited from pure hexamethyldisiloxane (HMDSO) vapours in low frequency powered plasma reactor have been investigated. The polymer thin layers were elaborated at different plasma treatment times. The surface characterization of the coated PI film is performed using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), refractive index, scanning electron microscopy (SEM), water droplet contact angle measurements and surface potential decay. The high carbon content revealed by ATR-FTIR analysis makes the coated surface PI films more hydrophobic. The water contact angle increased from 63° for untreated film to 115° after 10 min of HMDSO plasma coating. The coated PI surfaces were found to stay practically unchanged following storage of the samples in ambient conditions, indicating stable hydrophobic surface treatments. The increase of the refractive index indicates less porous structure. Scanning electron microscopy images showed a homogenous coating without crack. Surface potential evolution after corona charge deposition showed the retention of deposited charges at the surface of coated PI film. Correlation between these different analysis techniques results has been discussed. 相似文献
2.
To examine the feasibility of whey protein isolate (WPI) coating as an alternative oxygen barrier for food packaging, heat‐denatured aqueous solutions of WPI with various levels of glycerol as a plasticizer were applied on corona‐discharge‐treated low‐density polyethylene (LDPE) films. The resulting WPI‐coated LDPE films showed good appearance, flexibility and adhesion between the coating and the base film, when an appropriate amount of plasticizer was added to the coating formulations. WPI‐coated LDPE films showed significant decrease in oxygen permeability (OP) at low to intermediate relative humidity, with an Arrhenius behaviour and an activation energy of 50.26 kJ/mol. The OP of the coated films increased significantly with increasing relative humidity, showing an exponential function. Although the coated films showed a tendency to have less oxygen barrier and more glossy surfaces with increasing plasticizer content, differences in the OP and gloss values were not significant. Haze index and colour of the coated films were also little influenced by WPI coating and plasticizer content. The results suggest that whey protein isolate coating could work successfully as an oxygen barrier and have potential for replacing synthetic plastic oxygen‐barrier layers in many laminated food packaging structures. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
3.
Keun Taik Lee Julie M. Goddard Joseph H. Hotchkiss 《Packaging Technology and Science》2009,22(3):139-150
In order to functionalize the surface of blown low‐density polyethylene (LDPE) and cast polypropylene (CPP) films, and ultimately to maximize the attachment of active molecules onto them, the optimum treatment parameters of capacitively‐coupled radio‐frequency (13.56 MHz) oxygen plasma were investigated by using contact angle, toluidine blue dye assay, X‐ray Photoelectron Spectroscopy (XPS) and Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR‐FTIR). Contact angle values of LDPE and CPP samples decreased significantly after oxygen plasma treatment. They further decreased as the plasma power level increased. The treatment time had no substantial effect on contact angle value. The optimum treatment conditions for LDPE and CPP films for maximizing carboxyl functionality without causing observable surface changes were found to be 200 W/200 mTorr and 250 W/50 mTorr, respectively, when treated for 3 min. The maximum carboxyl group concentration obtained with LDPE and CPP films were 0.46 and 0.56 nmol/cm2, respectively. The percent of oxygen atoms on the surface of plasma‐treated LDPE and CPP films was determined by XPS analysis to be 22.6 and 28.7%, respectively. The ATR‐FTIR absorption bands at 1725–1700 cm?1 confirmed the presence of carboxylic acids on LDPE and CPP films. By exposing the plasma‐treated sample to air rather than water and treating films repeatedly with oxygen plasma, a higher carboxyl group concentration could be obtained. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
4.
M. V. Gorokhov V. M. Kozhevin D. A. Yavsin A. V. Voronin S. A. Gurevich 《Technical Physics Letters》2017,43(4):341-344
We have experimentally studied the action of high-power plasma flows on pure tungsten plates covered with multilayer films of tungsten nanoparticles formed by the method of laser electrodeposition. The samples were irradiated using a plasma gun producing hydrogen (helium) plasma flows with power density up to 35 GW/cm2. The resulting surface morphology was studied by scanning electron microscopy (SEM). SEM data showed that tungsten plates coated by nanoparticles are more resistant to the formation of microcracks than are pure tungsten plates. 相似文献
5.
Fangfang Sun Hee-Ryoung Cha KiEun BaeSuckwon Hong Jong-Man Kim Soo Hyung Kim Jaebeom Lee Dongyun Lee 《Materials Science and Engineering: A》2011,528(21):6636-6641
A multi-performance MWCNT-reinforced chitosan nanocomposite was fabricated by two methods: a freeze-drying process associated with the sublimation and compression (SAC) method; and the casting-evaporation (CE) method. We obtained ordered and multilayered structures with limited porosity, and well-dispersed MWCNT structures of the chitosan nanocomposite, especially with the SAC method. In the case of the nanocomposite films prepared by the CE method, the mechanical strength and elongation were significantly increased by up to about 40% compared with the pure chitosan films. On the other hand, the ordered and porous multilayered pure chitosan films prepared by the SAC method showed significantly lower tensile strength and elongation compared to the pure solid chitosan films. However, the relative enhancement of the mechanical properties of multilayered MWCNT/chitosan nanocomposites with porosity was higher, especially in terms of the elongation, which showed a twofold improvement in strain. The relaxed bond, which could be a relatively strong hydrogen bond, between the functional groups in the chitosan chains and the functionalized surface of the MWCNTs might be stretched under stress, thereby improving the ductility of the multilayered nanocomposite films. In addition, the viscoplastic behavior of the films by the CE method could become more active with increasing strain rate. Interestingly, ordered and porous pure chitosan films did not reveal the viscoplastic behavior; it rather presented strain softening and viscoelastic characteristics. However, the interaction between the chitosan chains and the surface-modified MWCNTs could regenerate viscoplasticity of the chitosan films. 相似文献
6.
Andrew J. Chetwynd Wei Zhang James A. Thorn Iseult Lynch Rawi Ramautar 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(21)
Nanomaterials (NMs) are promptly coated with biomolecules in biological systems leading to the formation of the so‐called corona. To date, research has predominantly focused on the protein corona and how it affects NM uptake, distribution, and bioactivity by conferring a biological identity to NMs enabling interactions with receptors to mediate cellular responses. Thus, protein corona studies are now integral to nanosafety assessment. However, a larger class of molecules, the metabolites, which are orders of magnitude smaller than proteins (<1000 Da) and regulate metabolic pathways, has been largely overlooked. This hampers the understanding of the bio–nano interface, development of computational predictions of corona formation, and investigations into uptake or toxicity at the cellular level, including identification of molecular initiating events triggering adverse outcome pathways. Here, a capillary electrophoresis–mass spectrometry based metabolomics approach reveals that pure polar ionogenic metabolite standards differentially adsorb to a range of 6 NMs (SiO2, 3 TiO2 with different surface chemistries, and naïve and carboxylated polystyrene NMs). The metabolite corona composition is quantitatively compared using protein‐free and complete plasma samples, revealing that proteins in samples significantly change the composition of the metabolite corona. This key finding provides the basis to include the metabolite corona in future nanosafety endeavors. 相似文献
7.
O. Prymak D. Bogdansk S.A. Esenwein M. Kller M. Epple 《Materialwissenschaft und Werkstofftechnik》2004,35(5):346-351
Plates of superelastic nickel‐titanium shape memory alloy (NiTi) were coated with calcium phosphate (hydroxyapatite) by high‐temperature plasma‐spraying. The porous layer of about 100 μm thickness showed a good adhesion to the metallic substrate that withstood bending of the plate but detached upon cutting the plate. The biocompatibility was tested by cultivation of blood cells (whole blood and isolated granulocytes [a subpopulation of blood leukocytes]). As substrates, pure NiTi, plasma‐spray‐coated NiTi and calcium phosphate‐coated NiTi prepared by a dip‐coating process were used. The adhesion of whole blood cells to all materials was not significantly different. In contrast, isolated granulocytes showed an increased adhesion to both calcium phosphate‐coated NiTi samples. However, compared to non‐coated NiTi or dip‐coated NiTi, the number of dead granulocytes adherent to plasma‐sprayed surfaces was significantly increased for isolated granulocytes (p<0.01). 相似文献
8.
Magdalena Rohrbeck JProf. Dr. Christian Fischer Prof. Dr. Stefan Wehner Dr. Jutta Meier Prof. Dr. Werner Manz 《真空研究与实践》2014,26(2):42-47
Polymers made of renewable resources increasingly replace conventional plastic materials made of petroleum. Socalled bioplastics can be found e. g. in food industry, for agricultural usage or in the medical field. The range of applications can be further expanded with specialized coating of their surface. Especially in case of food packaging and the usage within medical devices as well as the storage of these composite materials, sterilization or at least the partial reduction of microbial growth is an important issue which needs to be addressed early in the production process. In this work, a commercially available polyhydroxyalkanoate (PHA) pure bioplastic foil of 50 μm thickness was coated with 100 nm of diamond‐like carbon (DLC) and afterwards treated by four different standard methods of sterilization and / or disinfection, namely deep‐freezing, ultraviolet irradiation, autoclaving and immersion in ethanol. The surface morphology of treated DLC‐coated and uncoated samples was investigated and compared to the untreated DLC‐coated and uncoated samples using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Measurements exhibited damage of the composite for autoclaved and in ethanol immersed samples, whereas deep‐frozen and ultraviolet irradiated samples showed no structural changes. These findings clearly demonstrate deep‐freezing and ultraviolet irradiation to be appropriate methods for the disinfection and sterilization, respectively, of the DLC‐coated pure bioplastic foil. 相似文献
9.
This study examines platelet adhesion on surfaces that combine coatings to limit protein adsorption along with “anti‐platelet” nitric oxide (NO) release. Uncoated and poly‐2‐methoxyethylacrylate (PMEA) coated, gas permeable polypropylene (PP) membranes were placed in a bioreactor to separate plasma and gas flows. Nitrogen with 100/500/1000 ppm of NO was supplied to the gas side as a proof of concept. On the plasma side, platelet rich plasma (PRP, 1 × 108 cell/mL) was recirculated at low (60)/high (300) flows (mL/min). After 8 hours, adsorbed platelets on PP was quantified via a lactate dehydrogenase assay. Compared to plain PP, the PMEA coating alone reduced adsorption by 17.4 ± 9.2% and 29.6 ± 16.6% at low and high flow (p < 0.05), respectively. NO was more effective at low plasma flow. At 100 and 500 ppm of NO, adsorption fell by 37.9 ± 6.1% and 100 ± 4.7%, (p < 0.001), on plain PP. At high flow with 100, 500, and 1000 ppm of NO, adsorption reduced by 17.9 ± 17.8%, 46.4 ± 23.2%, and 100 ± 4.8%, (p < 0.001), respectively. On PMEA‐coated PP with only 100 ppm, adsorption fell by 69.7 ± 6.8 and 65.6% ± 16.9%, (p < 0.001), at low and high flows respectively. Therefore, the combination of an anti‐adsorptive coating with NO has great potential to reduce platelet adhesion and coagulation at biomaterial surfaces. 相似文献
10.
Mikko Tuominen M. Ek P. Saloranta M. Toivakka J. Kuusipalo 《Packaging Technology and Science》2013,26(4):201-214
The target of this study is to investigate the correlation between surface properties and heat sealability of flame‐treated low‐density polyethylene (LDPE) coating because it is vital to know how to modify the surface properties of LDPE coating without losing the heat sealing properties. Flame treatment showed a significant effect on the heat sealing properties of LDPE‐coated paper. For example, the heat sealing temperature of LDPE coating decreased or alternatively doubled, depending on the equivalence ratio (air–propane ratio) of flame treatment. In addition, the hot tack strength was significantly enhanced by flame treatment, which broadened the hot tack window of LDPE‐coated paper. The reason for the heat sealing performance of flame‐treated LDPE coating was believed to be related to the simultaneous reactions, that is, cross‐linking and chain scission, occurring on the LDPE surface. The molecular weight of LDPE surface increased or decreased, depending on the dominating reaction during flame treatment. This affected the chain mobility and the amount of chain interdiffusion across the seal interface and finally defined the heat sealing performance of LDPE‐coated paper. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
11.
The Protein Corona of Plant Virus Nanoparticles Influences their Dispersion Properties,Cellular Interactions,and In Vivo Fates 下载免费PDF全文
Andrzej S. Pitek Amy M. Wen Sourabh Shukla Nicole F. Steinmetz 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(13):1758-1769
Biomolecules in bodily fluids such as plasma can adsorb to the surface of nanoparticles and influence their biological properties. This phenomenon, known as the protein corona, is well established in the field of synthetic nanotechnology but has not been described in the context of plant virus nanoparticles (VNPs). The interaction between VNPs derived from Tobacco mosaic virus (TMV) and plasma proteins is investigated, and it is found that the VNP protein corona is significantly less abundant compared to the corona of synthetic particles. The formed corona is dominated by complement proteins and immunoglobulins, the binding of which can be reduced by PEGylating the VNP surface. The impact of the VNP protein corona on molecular recognition and cell targeting in the context of cancer and thrombosis is investigated. A library of functionalized TMV rods with polyethylene glycol (PEG) and peptide ligands targeting integrins or fibrin(ogen) show different dispersion properties, cellular interactions, and in vivo fates depending on the properties of the protein corona, influencing target specificity, and non‐specific scavenging by macrophages. Our results provide insight into the in vivo properties of VNPs and suggest that the protein corona effect should be considered during the development of efficacious, targeted VNP formulations. 相似文献
12.
目的确定SiO_x阻隔材料的电晕特性与印刷特性,研究其电晕处理规律以及印刷色彩再现的能力。方法采用磁控共溅射方法在PET表面制备不同含量SiO_x的复合阻隔材料,并采用电晕放电进行处理,利用接触角表征电晕放电后表面状态的变化;采用彩色喷墨打印方式,对处理后的复合薄膜表面进行印刷测试。结果 SiO_x质量分数较小时不具备抗电晕特性,当SiO_x质量分数达到50%左右时,即产生了抗电晕能力。结论印刷测试结果表明,经过电晕处理的复合薄膜色彩再现良好,可直接进行印刷。 相似文献
13.
Nanostructured composites have a wide variety of potential applications in microelectronics, chemical sensors, and electrochemical energy production. Here, we report the chemical, structural, and electrochemical characteristics of a nanostructured composite material formed from plasma-polymerized polypyrrole-coated Au fibers. The properties of the plasma-polymerized polypyrrole (PPPy) films were characterized by FTIR, X-ray photoelectron spectroscopy (XPS), and UV-Vis spectroscopy, as well as cyclic voltammetry (CV), and scanning electron microscopy (SEM). These spectroscopy analyses suggest that thermal treatment of the materials results in elimination of loosely-bound, low mass oligomers in the films. Mass spectral analysis of the plasma phase suggests that plasma polymerization of the pyrrole takes place on the substrate surface as a result of diffusion of radicals produced in the plasma. In addition, thermal treatment enhances the electrochemical properties of the PPPy films because of changes in the surface morphology and bulk structure of the films. However, as-deposited PPPy films coated on Au nanotubes demonstrate better electrochemical properties than as-deposited PPPy films coated on flat ITO electrodes as a result of the increase in surface area and decrease in film thickness. 相似文献
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15.
采用磁控溅射技术,在丙纶非织造布(PP)基材表面沉积厚度为0.5-3nm的纳米结构银薄膜,重点研究了PP基材经氩等离子体预处理前后对纳米结构银薄膜抗菌性能的影响。采用振荡烧瓶法测试样品的抗菌性能,利用原子力显微镜(AFM)观察氩等离子处理前后PP基材表面的形态变化,同时应用EDX对纳米结构银薄膜进行元素分布及定量分析。实验结果表明:在纳米结构银薄膜厚度相同的条件下,经氩等离子预处理的丙纶非织造布具有更好的抗菌性能;AFM分析表明,经氩等离子处理后的纤维表面有明显的刻蚀痕迹,纤维表面凹凸不平,形成很多微小的空隙,溅射出的银粒子不易团聚,活性增加,抗菌性能因此提高;而EDX结果分析表明,抗菌性能提高是由于经氩等离子处理后,银离子溶出总量增加的缘故。 相似文献
16.
Microstructure and Ablation Behavior of W Coating Prepared by Atmospheric Plasma Spraying for Zr/Cu Infiltrated C/C Composites 下载免费PDF全文
Zhe Zhou Zexu Sun Huang Wu Yicheng Ge Ke Peng Liping Ran Maozhong Yi 《Advanced Engineering Materials》2018,20(5)
17.
The effect of a plasma nitriding (PN) pre‐treatment on the fatigue performance of hard chromium (HC) plated AISI 4140 steel has been investigated by conducting a series of rotary bending fatigue tests at a frequency of 95 Hz. hourglass shaped test specimens of 4‐mm diameter had been plasma nitrided at 510°C for 4, 8 and 12 h. It was found that HC‐plated specimens with a coating layer of 23 ± 2 μm thickness showed approximately 33% reduction in fatigue strength when compared to quenched and tempered (Q&T) specimens. An application of the PN pre‐treatment before the plating process was effective in improving the fatigue performance of HC‐coated steel. An improvement of 71% in the fatigue strength of pre‐treated specimens was recorded as compared with the specimens, which were HC plated only. The results also indicated that prolonged nitriding time did not cause better improvement in the fatigue performance. 相似文献
18.
The decrease in the corona treatment effect with time and its influence on the flexographic printability of low‐density polyethylene‐coated paperboard were studied. After corona treatment, sheets were stored in different ways. Some sheets were stored in a laboratory atmosphere, while others were protected from exposure to light, air, moisture and dust in polyethylene bags. The tendency for ink to spread on the surfaces was studied using contact angle measurements. Printability was evaluated as print density, dot gain, uncovered (white) and mottling. The results obtained show that the surface energy of the protected sheets decreased with time, but not as much and not as quickly as that of the unprotected sheets. In the case of the protected sheets, the percentage uncovered areas and mottling remained constant, but for the unprotected sheets they increased with increasing time after the corona treatment. No significant differences were seen in the other print quality measures. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
19.
UV–Ozone Interfacial Modification in Organic Transistors for High‐Sensitivity NO2 Detection 下载免费PDF全文
Wei Huang Xinming Zhuang Ferdinand S. Melkonyan Binghao Wang Li Zeng Gang Wang Shijiao Han Michael J. Bedzyk Junsheng Yu Tobin J. Marks Antonio Facchetti 《Advanced materials (Deerfield Beach, Fla.)》2017,29(31)
A new type of nitrogen dioxide (NO2) gas sensor based on copper phthalocyanine (CuPc) thin film transistors (TFTs) with a simple, low‐cost UV–ozone (UVO)‐treated polymeric gate dielectric is reported here. The NO2 sensitivity of these TFTs with the dielectric surface UVO treatment is ≈400× greater for [NO2] = 30 ppm than for those without UVO treatment. Importantly, the sensitivity is ≈50× greater for [NO2] = 1 ppm with the UVO‐treated TFTs, and a limit of detection of ≈400 ppb is achieved with this sensing platform. The morphology, microstructure, and chemical composition of the gate dielectric and CuPc films are analyzed by atomic force microscopy, grazing incident X‐ray diffraction, X‐ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy, revealing that the enhanced sensing performance originates from UVO‐derived hydroxylated species on the dielectric surface and not from chemical reactions between NO2 and the dielectric/semiconductor components. This work demonstrates that dielectric/semiconductor interface engineering is essential for readily manufacturable high‐performance TFT‐based gas sensors. 相似文献
20.
采用等离子体电解氧化法在钛表面制备Ca-P-Si生物活性陶瓷氧化膜。将纯钛及等离子体电解氧化后纯钛两种样品分别浸在37℃的Hank模拟体液中,用电化学实验分析其电化学性能。动电位极化曲线和交流阻抗结果表明,经过等离子体电解氧化处理后纯钛的自腐蚀电位升高了0.7V,经过28d的浸泡,微弧氧化处理后钛的阻抗值仍接近未处理时的1.5倍。微孤氧化陶瓷膜提高钛基体耐腐蚀性能归因于外层的羟基磷灰石层及微弧氧化的致密内层形成隔离层将基体与溶液隔离,起到了抗腐蚀作用。 相似文献