The use of a micro-cavity discharge array at atmospheric pressure to investigate the spatial modification of polymer surfaces

A micro-cavity discharge array (2500 cavities of 50 µm² size) was operated in neon at atmospheric pressure to modify polystyrene (PS), fluorinated ethylene-propylene co-polymer (FEP) and polytetrafluoroethylene (PTFE) polymer surfaces and, with the injection of a polymerisable monomer (acrylic acid), to deposit patterned, thin polymeric coatings. The aim of this study was to investigate the utility of these micro-discharge sources in the surface treatment of polymers and for the patterned deposition of polymeric material. The influence of the driving frequency, treatment time and sample-array distance on polymer surface treatment was investigated. X-ray photoelectron spectroscopy (XPS) was used to explore the surface chemistry of the treated polymer surfaces and of the polymer deposits. It was found that increasing the micro-cavity discharge source driving frequency and/or treatment time and decreasing the sample-array distance all led to a significant decrease in surface energy as determined by water contact angle measurements. For a period of time, post treatment surface hydrophilicity degraded due to the well known “ageing effect” but stabilized after two days. Finally, it was demonstrated that the device could be used for the localized, array sized, deposition of acrylic acid. High resolution XPS analysis of the deposit registered a C 1s spectra typical of poly(acrylic acid) with a prominent peak centred at approximately 289.3 eV indicating a relatively high level retention of the original monomer functionality. These results demonstrate that micro-cavity discharges, operated at or near atmospheric pressure, can be used to both modify and locally deposit polymeric material.     

Surface modification of polyurethane membranes using RF-plasma treatment with polymerizable and non-polymerizable gases

Low-powered gas plasmas containing oxygen, nitrogen or acrylic acid (AA) monomer (vapour) were used to modify and introduce specific functionalities on the surface of polyurethane membranes (PUs). Plasma treated films were characterized by X-ray photoelectron spectroscopy (XPS), while the hydrophilicity of the surfaces were examined by contact angle measurements. Pervaporation data (PV) were obtained for untreated and treated PUs. The results showed that plasma treatment processes increase in all cases on the polar nature of the PUs studied. HR-XPS results demonstrated that O₂ treated PUs incorporated functionalities containing oxygen, while N₂ plasma incorporated nitrogen at the PUs surface. AA plasma treatment resulted in the incorporation of carbonyl groups directly at the PUs surface. The pervaporation results showed that AA plasma polymerization treated PUs had much higher selectivity for the separation of methanol from methyl-t-butyl ether (MTBE) than untreated and O₂, N₂ treated PUs. In the case of AA treatment it was found that a thin film, with similar chemical properties to the poly (acrylic acid), was formed on top of the PU membrane increasing the PV efficiency for the separation of the mixture.     

Al-Mg合金对2D石墨纤维网的润湿性及铺展速率分析

本文使用静滴法研究了不同Mg含量(3.2, 4.5, 6.5, 8.5, 10, 13, 17 wt.% Mg)的Al-Mg合金在M40石墨纤维网上的润湿行为,重点讨论了Mg元素含量对润湿性及铺展速率的影响。 随着Al-Mg合金中的Mg含量从3.2 wt.%增加至17 wt.%,初始润湿角从115o降低到88.5o,而最终润湿角则由 96.7o降低到71o。由于M40石墨纤维的表面组织性质与普通石墨有较大的区别,因此与高密度碳平板相比,Al-Mg合金在石墨纤维网上的初始润湿角更小。而润湿角随Mg含量的增加而减小主要是源于Mg含量的增加可以显著降低Al-Mg合金的表面张力。基于Dezellus方程,进一步计算了Al-Mg合金在石墨纤维网上的铺展速率,计算结果与实验结果基本吻合。基于Miedema模型计算得到的铺展速率系数k也与实验结果基本吻合,此结果证明了Miedema模型在铺展速率计算方面应用的合理性。计算与实验结果均表明Mg元素含量的增加虽然可以显著降低润湿角,但对铺展速率影响不大。     

模拟风沙环境下混凝土防护涂层抗冲蚀性能的研究

目的 研究不同类型的防护涂层对风沙环境下混凝土抗冲蚀性能的影响规律及作用机理,从而选取适合风沙环境且综合性能良好的混凝土防护涂层.方法 以聚氨酯、丙烯酸及环氧树脂为研究对象,对三种混凝土结构防护涂层进行了研究.通过接触角和显微硬度对涂层的物理及力学性能进行了分析,并利用模拟风沙环境侵蚀实验系统,在不同冲蚀参数下,对混凝土结构防护涂层体系的抗冲蚀性能的变化规律进行测试.结合混凝土防护涂层风沙冲蚀实验及扫描电镜表征,探究风沙环境下混凝土防护涂层的冲蚀机理.结果 相同冲蚀条件下,不同防护涂层的冲蚀率大小为:聚氨酯防护涂层>环氧树脂防护涂层>丙烯酸防护涂层.喷涂丙烯酸防护涂层试样的抗冲蚀性能比喷涂聚氨酯防护涂层的试样提升了约57.56％,比喷涂环氧树脂防护涂层的试样提升了约33.57％.冲蚀表面分形维数(Ds)的变化在一定程度上反映了不同冲蚀阶段的变化,结合Ds及被冲蚀后涂层表面的微观形貌特征,发现在低角度冲蚀时,受粒子拉应力影响,涂层表面发生了撕裂及脱粘现象,冲蚀率较高.在高角度冲蚀时,受粒子压应力影响,涂层表面出现隆起及空穴等塑性变形,冲蚀表面Ds增加,且在材料屈服应力范围内未造成损伤界面的脱落,故冲蚀率较低,显示出典型塑性材料冲蚀损伤的特征.结论 聚氨酯、丙烯酸及环氧树脂防护涂层体系,均能提高混凝土的抗冲蚀性能.结合防护涂层的接触角及硬度测试结果,发现丙烯酸防护涂层作为风沙环境中混凝土结构防护涂层时,效果较好,适用于该环境下的混凝土防护.不同防护涂层在受到冲蚀时,不存在明显的塑性变形和脆性破坏阶段,而是随冲蚀分量变化,涂层由塑性变形向脆性破坏过渡,且该现象存在于整个冲蚀过程中.     

疏水/超疏水Ti合金表面液滴的运动特性

采用激光加工技术在Ti6Al4V合金表面构建点阵微结构,利用自组装分子膜技术在微结构表面沉积低表面能物质,制备疏水/超疏水表面。采用自制测试系统测试液滴在试样表面的静态接触角和滚动角,用高速摄像机拍摄液滴滴落到试样表面的运动过程。结果表明,经激光加工和低表面能修饰可构建Ti6Al4V疏水/超疏水表面,其最大接触角为151.4°,表面静态接触角随点阵间隔的增大而减小;液滴静态接触角与液滴滴落高度相关,同一表面上的液滴静态接触角由最后一次滴落高度决定。液滴滴落到水平试样表面的铺展系数由试样表面粗糙度和静态接触角决定,表面粗糙度和静态接触角越大,液滴铺展系数越小。当滴落高度从0 mm增大到20 mm时,铺展系数的增大幅度约为50%。     

微球构筑防污减阻涂层的制备

通过乳液聚合法制备表面具有聚乙二醇（PEG）支链的聚苯乙烯微球,将所得微球悬浮液与丙烯酸酯聚合物乳液共混,采用涂覆的方式制备仿生减阻涂层。考察微球的组成及其粒度、不同微球含量对涂层表面形貌及润湿性的影响,研究交联对涂层稳定性的影响。采用异硫氰酸荧光素标记的牛血清蛋白（BSA-FITC）考察不同微球含量对涂层抗蛋白吸附性的影响,运用扭矩测定法考察了涂层的减阻性能。结果表明：具有PEG支链的聚苯乙烯微球粒径具有单分散性,所得仿生涂层表面分布着大量的聚合物微球,且随着微球质量分数增大,涂层水接触角减小、亲水性增强;交联反应显著改善涂层的耐水稳定性;与未添加微球的涂层相比,当微球质量分数为15%时,涂层的抗蛋白吸附效率最大可达到97%,当微球质量分数为6%时,涂层的减阻率最大可达到21%。     

纯钽表面微弧氧化“类骨小梁”状多孔涂层的细胞相容性

目的 提高医用纯钽的生物活性，利用微弧氧化(MAO)技术在其表面制备出“类骨小梁”状分级多孔涂层，并对比该涂层与传统“火山坑”状MAO涂层以及机械抛光纯钽表面在表面粗糙度、亲水性以及细胞相容性方面的差异。方法 使用0.1 mol/L Na₂B₄O₇和0.05 mol/L Na₃PO₄电解液在纯钽表面分别制备出“类骨小梁”状及“火山坑”状多孔涂层(分别命名为B-MAO和P-MAO涂层)。采用扫描电镜、X射线衍射以及X射线光电子能谱对不同结构涂层进行形貌观察和相组成分析，使用十字划格法评价涂层结合强度，使用激光共聚焦显微镜测定涂层的表面粗糙度，使用接触角仪测量其亲水性，并将小鼠前成骨细胞(MC3T3-E1)接种于材料表面，对比不同形貌状态对细胞铺展、增殖以及成骨分化的影响。结果 MAO涂层物相主要为Ta₂O₅。B-MAO涂层由于内部孔隙度高，应力释放充分，涂层结合强度高，而P-MAO涂层则因具有分层现象和较大的残余应力，易从基体剥落。抛光...     

高透光氧化硅涂层的低温制备及微观结构调整

目的提供一种在真空装饰领域能够广泛应用的具有防护、功能性的氧化硅涂层制备方法,为具体应用中涂层工艺参数的选择提供指导。方法采用PECVD技术,通过改变O2与HMDSO配比,低温制备具有不同微结构的氧化硅涂层。采用扫描电镜观察涂层的表截面微观形貌,采用X射线衍射仪、傅里叶变换红外光谱仪、X射线光电子能谱仪、激光共聚焦拉曼光谱仪分析涂层的微结构及成分,采用紫外分光光度计表征涂层透光性,采用纳米压痕仪表征涂层的力学性能,采用接触角仪表征涂层的表面润湿性。结果所制备的氧化硅涂层表面光滑,结构致密。随反应气体中O2配比的增加,涂层结构由Si O逐渐过渡为Si O2,并掺杂有少量非晶碳,其光学透过率增加,力学性能下降,亲水性增加。当碳含量最低时,涂层具有最优异的透光性及最好的亲水性,在全可见光波段范围内透过率接近100%,与水接触角为45.38°;当碳含量最高时,涂层具有最优异的力学性能,硬度为13.5 GPa,H/E为0.11。结论采用PECVD方法能够在低温下获得光学透明、具有一定硬度、表面易清洁的氧化硅涂层,通过气体控制能够对涂层微结构及性能进行调节,从而适用于不同需求的功能装饰。     

The surface and the linear tension and the contact angle of a small drop under isothermal conditions

A small lying drop is investigated considering the linear tension at the three-phase boundary under thermodynamic and mechanical equilibrium. Formulas for the surface tension at the liquid-vapor interface, the linear tension, and the contact angle are found by the Gibbs dividing surface method. It is shown that the surface tension and the contact angle decrease while the absolute value of the linear tension increases with decreasing radius of the surface curvature. Comparison of theoretical predictions with experimental data obtained by atomic-force microscopy shows a satisfactory agreement and evidences that the linear tension must be negative.     

POSS改性丙烯酸涂层的耐刮擦及紫外防护性能

丙烯酸树脂基涂层具有良好的耐候性,但其力学性能较差,耐刮擦及摩擦磨损性能不足等缺点易导致其使用寿命降低。为改善其耐刮擦及摩擦磨损性能,进一步提高其耐候性和延长使用寿命,采用溶胶凝胶法合成了八乙烯基多面体低聚倍半硅氧烷(OvPOSS),进一步将其与丙烯酸树脂(PMB)原位复合改性制备了不同OvPOSS添加量的有机无机杂化树脂。利用光镜、接触角测量仪、显微硬度仪等表征了OvPOSS改性树脂制备的涂层在紫外辐照前后的表面形貌、接触角、硬度等;采用纳米划痕仪和摩擦试验机研究了涂层改性前后的耐刮擦和摩擦磨损性能。结果表明：当添加OvPOSS质量分数为10%时,改性涂层的各方面性能最佳。与未改性的丙烯酸涂层相比,OvPOSS的加入显著改善了OvPOSS/PMB复合涂层的硬度,抗紫外线性,耐刮擦和摩擦磨损等性能。     

The enhancing effect of surface coatings on cast-in bonding of steel and titanium inserts in aluminium castings

Insertion bonding of mild steel and titanium pipes in aluminium castings was performed in two ways; either by holding paired pipe and aluminium cylinder specimens at constant high temperatures, or by pouring molten aluminium into sand moulds containing inserts. The surfaces of the inserts were electroplated using Ag or Au, or spray coated with Al-Si alloy. The bonding was evaluated by shear strength measurements and microstructure observations. To verify the effect of surface coatings, the contact between the molten aluminium and the specimens was observed. At constant high temperatures, coated steels showed good metallurgical bonding when they were maintained for about 200 s in contact with molten aluminium. The time necessary for bonding was shorter with titanium inserts. In bonded specimens, alloyed microstructures were observed at the interfaces. There was no bonding with uncoated specimens. All coatings used were effective when poured, but preheating of the moulds was necessary to allow sufficient solidification time for the melt/insert volume ratios which were 32 and 36. Process analysis by the finite difference method showed that bonding required a period of liquid phase contact of the melt with the inserts. Observation of aluminium droplet contact with the inserts showed that uncoated surfaces of steel and titanium are not wetted by the melt due to stable oxide skins. With Ag electroplating, aluminium droplets can make wet contact with the specimens. The contact angle decreased from about 140° in uncoated specimens to 15°-45° with Ag plating. The plating prevents surface oxidation of the inserts and promotes wet contact when the active aluminium liquid surface is exposed. The Al-Si alloy spray coating has some effect in promoting wettability, but it is inferior to Ag plating.     

氟改性和硅改性丙烯酸聚氨酯涂层的制备及环境行为

目的研究氟改性和硅改性丙烯酸聚氨酯涂层在不同环境中的失效行为。方法通过溶液聚合法制备具有一定羟基含量的丙烯酸酯树脂,再将丙烯酸树脂与多异腈酸酯固化剂配合,获得丙烯酸聚氨酯涂层。通过在丙烯酸酯合成中引入含氟丙烯酸酯单体,制得氟改性丙烯酸聚氨酯涂层;通过在固化过程中引入氨基硅油,制得硅改性丙烯酸聚氨酯涂层。利用傅里叶变换红外光谱(FT-IR)分析涂层的化学组成。对涂层试样进行温度环境实验(室温和100,150℃)、湿热环境实验和氙灯老化实验,分析涂层疏水性、光泽度等表面特性的变化。结果氟、硅改性有效提高了涂层的疏水性。未改性、氟改性和硅改性三种涂层在100℃以下的环境中服役时,疏水性和光泽度比较稳定。硅改性涂层在150℃的高温环境中较未改性和氟改性涂层失效慢。湿热环境对三种涂层的接触角和光泽度等性能影响不大。氟改性涂层在氙灯老化环境中的失效程度较另外两种涂层轻。结论氟改性涂层耐光老化性能较好,硅改性涂层耐温性较好。     

Influence of reducers on nanostructure and surface energy of silver coatings and bacterial adhesion

The high incidence of infections caused by the use of implanted biomedical devices has a severe impact on human health and health care costs. Many studies suggest a strong antimicrobial activity of silver-coated medical devices. However no studies have been reported on the effect of surface energy of silver coatings on bacterial adhesion. In this paper, 4 types of silver coatings with various surface energies were prepared on stainless steel plates using AgNO₃ based electroless plating solutions with four different reducing agents, formaldehyde, hydrazine, glucose and potassium sodium tartrate tetrahydrate, respectively. The morphology and surface energy of the silver coatings were characterized with an Atomic Force Microscope and a Dataphysics OCA-20 contact angle analyzer, respectively. The anti-bacterial performance of the silver coatings was evaluated with Pseudomonas aeruginosa PA01, which frequently causes medical device-associated infections. The experimental results showed that bacterial adhesion decreased with the total surface energy of the coatings decreasing, but decreased with the electron donor component increasing. All the silver coatings performed much better than stainless steel in reducing bacterial attachment. The extended DLVO theory was used to explain bacterial adhesion behavior.     

多孔Ti3Zr2Sn3Mo25Nb钛合金表面活性次级微孔涂层的制备及其成骨性能

为提高多孔医用钛合金的生物活性,以实现快速骨整合,首先利用微弧氧化法在多孔Ti3Zr2Sn3Mo25Nb(TLM)合金表面制备出含Ca、P的次级微孔涂层,并通过水热处理在此涂层表面生成羟基磷灰石.通过XRD、SEM和EDS分析了活性次级微孔涂层的相组成、微观形貌和元素特征,通过接触角测试试验对比研究了TLM合金表面改性前后的亲水性变化,并进一步通过动物试验检测了表面活性次级微孔涂层改性后多孔TLM合金的成骨性能.结果表明,微弧氧化处理可在多孔TLM表面形成规整的含Ca、P相的次级微孔层,水热处理后次级微孔层的亲水性增强,且具有良好的成骨诱导性能.     

Ti/TiB2多层镀层的组织和性能研究

为了进一步提高超硬TiB2镀层与基体的结合力,采用磁空溅射法在高速钢表面上制备了多层相间的Ti/TiB2超硬镀层.利用多种实验方法测试和研究了镀层的组织结构,形貌,表面粗糙度,硬度和与基体的结合力.结果表明,镀层的Ti/TiB2相间层数对这些性能有很大的影响.当层数从二逐渐增加到十二,TiB2镀层的（001）织构逐渐消失而变成无择优取向,镀层表面粗糙度增加,但镀层硬度基本不变.只有当层数为十二时,镀层硬度才明显降低.结果也表明,多层镀层可有效地提高镀层与基体的结合力,并存在着一最佳的多层结合.本文也对多层结构对其它组织和性能特征的影响进行了分析.     

Tribological properties of titanium aluminides coatings produced on pure Ti by laser surface alloying

Titanium aluminides coatings were in-situ synthesized on a pure Ti substrate with a preplaced Al powder layer by laser surface alloying. The friction and wear properties of the titanium aluminides coatings at different normal loads and sliding speeds were investigated. It was found that the hardness of the titanium aluminides coatings was in the following order: Ti₃Al coating > TiAl coating > TiAl₃ coating. Friction and wear tests revealed that, at a given sliding speed of 0.10 m/s, the wear volume of pure Ti and the titanium aluminum coatings all increased with increasing normal load. At a given normal load of 2 N, for pure Ti, its wear volume increased with increasing sliding speed; for the titanium aluminides coatings, the wear volume of Ti₃Al coating and TiAl coating first increased and then decreased, while the wear volume of TiAl₃ coating first decreased and then increased with increasing sliding speed. In addition, the friction coefficients of pure Ti and the titanium aluminides coating decreased drastically with increasing sliding speed. Under the same dry sliding test conditions, the wear resistance of the titanium aluminium coatings was in the following order: Ti₃Al coating > TiAl coating > TiAl₃ coating.     

碳钢材料表面化学转化膜的防结蜡研究

利用化学转化与热处理的方法在钢铁表面制备了一种防结蜡涂膜,在含蜡的油水环境中,涂膜表面几乎没有蜡晶的沉积粘附,钢铁表面经过这种处理之后表现出了很好的防结蜡效果。研究表明,水和液体石蜡对涂层膜的润湿性不同是防结蜡的重要因素,在水中,蜡在这种涂膜表面的接触角高达158°,表现出明显的亲水憎油特征,这使得涂膜在含水原油中优先吸附一层水膜,而这层水膜可以阻止含蜡油水相与钢铁表面的直接接触,从而抑制蜡晶的沉积与粘附。     

含氟低表面能修饰的超双疏涂层制备及其性能

目的 制备具有良好机械稳定性和化学稳定性的超双疏涂层材料。方法 采用三种尺寸的微纳米二氧化硅和环氧树脂制成微纳米凹凸结构,在此基础上修饰低表面能的氟碳单分子层,制备超疏水超疏油涂层。分别利用扫描电子显微镜、原子力显微镜和X射线光电子能谱,对涂层表面的形貌和成分进行分析。通过接触角测量仪测试涂层表面的接触角和滚动角。经过砂纸摩擦、耐化学腐蚀和耐溶剂性能测试,分别评价超双疏涂层材料的耐磨损性和化学稳定性。结果 涂层对水、乙二醇和花生油等表面张力在34~72 mN/m范围内的液体具有超疏特性。砂纸上机械摩擦5次循环后,对花生油的接触角保持在155?以上,滚动角保持在5?以下;摩擦10次循环后,对水和乙二醇的接触角均保持在154°以上,滚动角保持在2.5?以下。涂层经pH=14的碱溶液和正庚烷浸泡,168 h后,对水和乙二醇仍保持超疏性能;96 h后,与花生油接触角在153?以上,滚动角在10?~20?之间。结论 该涂层具有良好的超疏水超疏油性能及良好的耐磨损性和化学稳定性,在工业领域具有较大的潜在应用价值。     

Plasma-electrolytic formation of Ta-containing oxide coatings on titanium. Their composition and properties

Coatings with a thickness of 2–18 μm that contain up to 20 at % tantalum and Ta₂O₅ oxide phase are formed in an aqueous NH₄[TaF₆]-containing electrolyte for 2 min. The coatings are pierced with pores with a size of from 0.5 to 2 μm. The number of pores in the coatings can be decreased by additionally applying a Ta-containing paste to the surface. The contact angle of the coatings in distilled water is 68°–85°. This approach is promising for application of Ta-containing coatings on titanium implants and stents for increasing their corrosion resistance, chemical inertness, and biocompatibility.     

FeNiBSiCe喷熔层微动磨损特性

利用氧-乙炔火焰喷熔方法在45号钢表面制取了FeNiBSiCe喷熔层,在SRV球盘摩擦磨损试验机上研究了FeNiBSiCe合金的摩擦磨损行为,用扫描电子显微镜(SEM)、场发射扫描电镜(FEGSEM)和能量色散谱仪(EDS)等技术分析了喷熔层的表面、截面及磨损面形貌.结果表明,FeNiBSiCe喷熔层的耐磨性优于SAE52100钢,喷熔层磨损率随滑动速度增加,先快速降低,随后趋于缓慢,最后上升.摩擦系数随滑动速度的增大而增加,然后趋于稳定.磨损机理是低载荷下为微观切削和疲劳脱层,在相对高载荷下和滑动速度较高时产生显微裂纹,且在涂层表面形成了一层氧化物磨屑层,缓解了微动磨损.