低温等离子体接枝改性聚四氟乙烯薄膜表面无钯化学镀铜

通过低温等离子体接枝改性方法将丙烯酸(Acrylic acid,AAc)接枝聚合于聚四氟乙烯(Polytetrafluoroethylene,PTFE)薄膜表面,随后进行无钯化学镀铜,制备出表面镀铜的PTFE薄膜(PTFE-g-PAAc-Cu)。衰减全反射傅里叶变换红外光谱(ATR-FTIR)测试结果表明,丙烯酸成功地接枝于PTFE薄膜表面;通过扫描电镜(Scanning electron microscopy,SEM)和原子力显微镜(Atomic force microscopy,AFM)观察发现,镀铜均匀沉积于PTFE薄膜表面;3M胶带粘贴方法(ASTM D3359标准)评估结果表明,铜层与PTFE薄膜粘结牢固,3M胶带未能够将铜层与PTFE薄膜分离开;电性能测试结果表明,PTFE-g-PAAc-Cu的表面电阻(Rs)降至1.27′10~(-2)Ω/sq,电阻率降至50.1μΩ?cm,其导电性由绝缘体提高到导体水平(导体的电阻率范围为1~10~3μΩ?cm),有望在柔性覆铜板领域获得应用。     

低能氦离子辐照对钨和钼材料的表面损伤作用

钨和钼材料具有高熔点、高热导率、低溅射率等优点成为国际热核实验反应堆计划中面向等离子体材料的候选材料。因此研究钨和钼材料的辐照损伤行为对于认识面向等离子体材料的辐照损伤机制具有重要意义。本文采用120 e V的He+在873 K对钨和钼材料进行辐照实验,利用纳米压痕仪与导电模式原子力显微镜(Conductive Atomic Force Microscopy,CAFM)相结合,原位比较了钨和钼材料在辐照前后的表面形貌、表面微结构以及表层缺陷分布的变化特征。结果表明,低能He+辐照会导致钨和钼材料的近表面产生纳米量级氦泡缺陷,这些氦泡缺陷的存在使得样品表面产生绒毛或波浪状结构。纳米压痕深度分析和扫描电镜的分析结果表明,低能He+辐照会对Mo材料产生明显的刻蚀作用。本工作对于进一步认识低能氦离子辐照对面向等离子体材料的辐照损伤作用具有一定的科学参考意义。     

低能氦等离子体低温条件下钨材料的表面形貌

为研究氦等离子体在钨表面造成的表面纳米结构,利用荷兰基础能源研究所Pilot-PSI直线等离子体发生装置在673 K温度下,对钨材料进行了低能（40 eV）高束流强度（4×10²³ m^-2•s^-1）氦等离子体辐照。实验结果表明,辐照后钨材料表面出现了多种不同形态的纳米结构,表面纳米结构和晶粒的表面法向之间存在明显关联。在表面法向为［111］的晶粒表面出现三角形的纳米结构,在［110］取向的晶粒表面出现条带状的纳米结构,而在［001］取向的晶粒表面没有明显的结构出现。晶粒表面的纳米结构尺寸在50 nm左右,高度起伏在5 nm以下。另外,氦等离子体辐照会造成晶界处的高度差,在25 nm左右。分析推测氦等离子体辐照造成的晶粒表面和晶界的形貌可能是由近表面的气泡所导致的。     

低温等离子体改性聚乙烯表面的自由基过程

以电子自旋共振波谱仪(ESR)为主要手段,研究了聚乙烯等五种聚合物等离子体改性过程中表面自由基的生成及转化。等离子体辐照的聚合物首先在表面生成烷基自由基,当与空气接触时,烷基自由基转化成过氧化自由基,在聚合物表面引入极性基因是通过过氧化自由基的反应完成的。     

载能离子束技术在堆用锆合金中的应用

锆合金是重要的反应堆用材料，其在堆中的耐腐蚀能力、耐辐照能力以及力学性能对反应堆效益和安全有重要影响。本文对近年来国内外关于离子注入、重离子模拟辐照等载能离子束技术在堆用锆合金表面改性、辐照行为以及元件后处理等方面的理论和应用研究进行了总结。     

低能大流强氦离子辐照对钼的表面损伤作用

钼(Mo)材料被作为托卡马克装置中面向等离子体材料的候选材料被广泛研究,因此研究钼材料的辐照损伤行为对于认识聚变堆关键材料的辐照损伤机制具有重要意义。采用低能(100 e V)、大流强(约1021 ions·m-2·s-1)He+在600 oC对钼样品进行辐照实验,考察了离子辐照剂量和退火温度变化对钼材料的表面损伤作用。分别采用扫描电镜(Scanning Electron Microscope,SEM)和无损伤的导电原子力显微镜(Conductive Atomic Force Microscopy,CAFM)检测技术对辐照前后样品的微观形貌、微结构演化以及内表面缺陷分布等进行了对比研究。结果表明,He+辐照会诱导钼样品晶粒尺寸的增加,钼材料表面的晶粒取向会影响辐照缺陷的分布。这对于探索抑制材料辐照损伤的新方法具有重要的指导意义。     

PTFE的辐射裂解、交联及其应用

聚四氟乙烯（PTFE）是一种性能优异的工程塑料,通常被认为是典型的辐射裂解材料。PTFE可以在不同条件下实现裂解并生成PTFE微粉。在高于PTFE的熔点即温度为330～340℃,真空或惰性气氛下进行辐照,可实现PTFE的交联。本工作综述了PTFE辐射裂解和交联研究的历史和最新进展,并对交联PTFE在润滑材料、燃料电池、光刻等领域的应用进行了介绍。     

强脉冲离子束材料表面改性研究进展

强脉冲离子束材料表面改性技术是正在发展中的新的材料表面改性技术。近四、五年来 ,我们围绕发展强脉冲离子束材料表面改性技术对其主要机制 (强脉冲能量效应 )、离子辐照诱发的热力学过程、表面熔坑现象及大面积均匀离子束技术开展了比较全面的基础性研究。研究表明 ,强脉冲离子束改性除了离子注入的元素掺杂效应外 ,其更可利用强脉冲能量沉积诱发的热力学效应 ,有望突破离子射程对改性层厚度的限制 ,并高效利用离子剂量和能量 ,成为新一代低成本、高效率、高生产率、实用化的离子束材料改性与合成工艺。本文对于上述研究的主要进展和相关问题进行了总结和评论     

含硅丙烯酸酯在紫外光固化涂料中的应用研究

合成了氨基硅油改性丙烯酸酯(AMPA),将其与PTFE微蜡粉、PE改性PTFE微蜡粉作为表面改性剂加入到紫外光(UV)固化涂料中,用红外光谱对固化前后进行了表征,研究了其对UV固化膜耐磨性的影响,考察了固化膜表面元素的富集现象,并测试了固化膜表面水接触角和光泽度的变化。研究结果表明,表面改性剂具有自润滑的作用,少量加入即能显著地提高固化膜的耐磨性,含硅改性丙烯酸酯(AMPA)的质量分数由0.0%增加到1.0%时,光固化膜耐磨测试质量损失由22.8mg下降到9.2mg,表面水接触角由43.3o增加到100.3o,表面光泽度由113.5°下降到95.5°。     

强脉冲离子束材料表面改性研究进展

强脉冲离子束材料表面改性技术是正在发展中的新的材料表面改性技术。近四、五年来,我们围绕发展强脉冲离子束材料表面改性技术对其主要机制(强脉冲能量效应)、离子辐照诱发的热力学过程、表面熔坑现象及大面积均匀离子束技术开展了比较全面的基础性研究。研究表明,强脉冲离子束改性除了离子注入的元素掺杂效应外,其更可利用强脉冲能量沉积诱发的热力学效应,有望突破离子射程对改性层厚度的限制,并高效利用离子剂量和能量,成为新一代低成本、高效率、高生产率、实用化的离子束材料改性与合成工艺。本文对于上述研究的主要进展和相关问题进行了总结和评论。     

利用同步辐射进行氟塑料的表面改性与微器件制造研究

It is well-known that fluorinated polymers are very unique polymer materials because of their distinguished properties, such as high electrical resistivities, chemical and thermal stabilities, bio-compatibilities, etc. However,polytetrafluoroethylene (PTFE) is degraded by ionizing radiation with a low dose through main chain scission, and the mechanical properties are seriously deteriorated. In early 1990's, it was found that irradiation for PTFE at elevating temperature enhances recombination of radicals induced by ionizing radiation. Thus, crosslinked PTFE had been obtained[1,2]. The crosslinked PTFE shows remarkable improvements for the radiation durability and mechanical properties, etc.We have performed micro-fabrication by means of synchrotron radiation (SR) for various kinds of PTFEs including crosslinked PTFEs. The direct photo--etching technique using SR is known as TIEGA() technology,which has been developed by Sumitomo Heavy Industries, Ltd. The technology was applied for the micro-fabrication of fluorinated polymers. It has been found that etching rates obtained for crosslinked PTFEs were much larger than those of the non-crosslinked. The fact is strange from the viewpoint of radiation durability of crosslinked PTFEs. Hence, the results are not described by simple consideration such as the G-values of main chain scission. We have proposed that the etching rates should be controlled by the complex mechanism through at least two different steps as polymer decomposition and fragment desorption mechanisms.On the other hand, we have found that abnormal reactions were induced at the surface region under the SR etching for the various kinds of fluorinated polymers. Through the measurements using differential scanning calorimetory (DSC) and solid state 19F-NMR, we have confirmed crosslinking reactions for the polymers even in solid states. This reaction should be induced by the very high density radicals formation and their recombination in very localized area of the polymers under the SR etching processes.     

RTL study of structural modifications in irradiated PTFE

The exposure of polytetrafluorethylene to the action of high energy radiation is examined by radiation thermoluminescence. The radiolysis causes the formation of various traps, which correspond to four maxima in the glow curve of PTFE. The activation energy of molecular motion is discussed. The modification of emission intensity at a large dose range is evaluated for three glow maxima that appear at 139, 173 and 205 K. The RTL emission is correlated with different types of oxygenated products that are formed during the radiolysis of PTFE. Changes in other properties like molecular mass, density, crystallinity are investigated for emphasizing the radiodegradation in this matrix. The mechanism of RTL emission is explained by the recombination of thermalized electrons with positive intermediates.     

Thermal radiation properties of PTFE plasma

To illuminate the thermal transfer mechanism of devices adopting polytetrafluoroethylene (PTFE) as ablation materials,the thermal radiation properties of PTFE plasma are calculated and discussed based on local thermodynamic equilibrium (LTE) and optical thin assumptions.It is clarified that line radiation is the dominant mechanism of PTFE plasma.The emission coefficient shows an opposite trend for both wavelength regions divided by 550 nm at a temperature above 15 000 K.The emission coefficient increases with increasing temperature and pressure.Furthermore,it has a good log linear relation with pressure.Equivalent emissivity varies complexly with temperature,and has a critical point between 20 000 K to 25 000 K.The equivalent cross points of the average ionic valence and radiation property are about 10 000 K and 15 000 K for fully single ionization.     

Graft Polymerization of Acrylic Acid on a Polytetrafluoroethylene Panel by an Inductively Coupled Plasma

Surface modification on a polytetrafluoroethylene (PTFE) panel was performed with sequential nitrogen plasma treatments and surface-initiated polymerization. By introducing COO– groups to the surface of the PTFE panel through grafting polymerization of acrylic acid (AA), a transparent poly (acrylic acid) (PAA) membrane was achieved from acrylic acid solution. Grafting polymerization initiating from the active groups was achieved on the PTFE panel surface after the nitrogen plasma treatment. Utilizing the acrylic acid as monomers, with COO– groups as cross link sites to form reticulation structure, a transparent poly (acrylic acid) membrane with arborescent macromolecular structure was formed on the PTFE panel surface. Analysis methods, such as FTIRmicroscopy and XPS were utilized to characterize the structures of the macromolecule membrane on the PTFE panel surface. A contact angle measurement was performed to characterize the modified PTFE panels. The surface hydrophilicities of modified PTFE panels were significantly enhanced after the plasma treatment. It was shown that the grafting rate is related to the treating time and the power of plasma.     

聚四氟乙烯的CH4/O2混合气体等离子体表面亲水改性研究

利用ＣＨ４／Ｏ２混合气体等离子体对聚四氟乙烯（ＰＴＦＥ）进行表面改性,利用角发辨ＸＰＳ和接触角对改性效果进行表征。结果表明：ＣＨ４／Ｏ２混合气体等离子体处理,在一定条件下可较好地改善ＰＴＦＥ的表面亲水性。对等离子体处理机理进行了探讨,认为在处理过程中存在相互影响的聚合、刻蚀和氧化作用,而Ｏ２等离子体的刻蚀作用对ＰＴＦＥ的表面亲水改性起着不良的影响。     

利用乙醇等离子体对PTFE进行表面改性

利用乙醇等离子体对聚四氟乙烯进行表面亲水改性处理，通过接触角测量，Ｘ射线光电子能谱对改性后的ＰＴＦＥ进行分析，表明乙醇等离子体处理可通过等离子体聚合在ＰＴＦＥ表面形成含碳，氧的覆盖层，改善了ＰＴＦＥ的表面亲水性，并有较好的表面动力学性质，获得了表面亲水性可以保持约５０ｄ。     

In-situ reduction of silver by surface DBD plasma: a novel method for preparing highly effective electromagnetic interference shielding Ag/PET

Electromagnetic interference(EMI) shielding composites with good flexibility and weatherability properties have attracted increased attention. In this study, we combined the surface modification method of sub-atmospheric pressure glow discharge plasma with in situ atmospheric pressure surface dielectric barrier discharge plasma(APSDBD) reduction to prepare polyethylene terephthalate supported silver(Ag/PET). Due to the prominent surface modification of PET film, mild plasma reduction, and effective control of the silver morphology by polyvinylpyrrolidone(PVP), a 3.32 μm thick silver film with ultralow sliver loading(0.022 wt%) exhibited an EMI shielding efficiency(SE) of 39.45 d B at 0.01 GHz and 31.56 d B at 1.0 GHz(30 d B in the range of 0.01–1.0 GHz). The SEM results and EMI shielding analysis indicated that the high performance originated from the synergistic effect of the formation of silver nanoparticles(Ag NPs) with preferentially oriented cell-like surface morphologies and layer-by-layer-like superimposed microstructures inside, which demonstrated strong microwave reflection properties. Fourier transform infrared spectrometer and x-ray diffractometer showed that the surface structures of the heat-sensitive substrate materials were not destroyed by plasma.Additionally, APSDBD technology for preparing Ag/PET had no special requirements on the thickness, dielectric constant, and conductivity of the substrate, which provides an effective strategy for manufacturing metal or alloy films on surfaces of heat-sensitive materials at a relatively low cost.     

A low power 50 Hz argon plasma for surface modification of polytetrafluoroethylene

The characteristics of a low power 50 Hz argon plasma for surface treatment of polytetrafluoroethylene (PTFE) film is presented in this article. The current–voltage behavior of the discharge and time-varying intensity of the discharge showed that a DC glow discharge was generated in reversed polarity at every half-cycle. At discharge power between 0.5 and 1 W, the measured electron temperature and density were 2–3 eV and ∼10⁸ cm⁻³, respectively. The optical emission spectrum of the argon plasma showed presence of some 'impurity species' such as OH, N₂ and H, which presumably originated from the residual air in the discharge chamber. On exposure of PTFE films to the argon glow plasma at pressure 120 Pa and discharge power 0.5 to 1 W, the water contact angle reduced by 4% to 20% from the original 114° at pristine condition, which confirms improvement of its surface wettability. The increase in wettability was attributed to incorporation of oxygen-containing functional groups on the treated surface and concomitant reduction in fluorine as revealed by the XPS analysis and increase in surface roughness analyzed from the atomic force micrographs. Ageing upon storage in ambient air showed retention of the induced increase in surface wettability.     

Fusion energy conversion in magnetically confined plasma reactors

One of the most pressing problems of this century is to solve the energy supply problem and in particular the development of fusion energy technology. Fusion powers the Sun and stars, but on Earth is difficult to achieve in a controlled manner. The International Thermonuclear Experimental Reactor (ITER) is the most technologically advanced machine where net energy from fusion is envisaged to be produced. But this will not be easy, since there are still open issues of plasma confinement, reactor materials, fuel supply, and heat removal. Efficient conversion of fusion energy into the thermal energy in a thermonuclear reactor is, therefore, of great technological relevance and in this paper the energy conversion in magnetically confined plasma reactors is addressed. The chamber wall surrounding the plasma is built from the plasma facing components and from the blanket and divertor modules where the fusion energy is converted into the thermal energy, tritium is produced, and the external components of the chamber are shielded from radiation. The useful materials for building the chamber wall components are low neutron activation steels, refractory metal alloys, and carbon fibre and silicon carbide reinforced composites. The suitable coolants of these components are high pressure helium gas and lithium-based liquid metals and molten salts, where the latter can also serve as tritium breeders. Some of these components will be tested in ITER and eventually may be employed for building demonstration fusion power plants envisaged to become operational during the second half of this century. High performance fusion energy conversion concepts being investigated include: Solid and liquid breeder blankets, separately cooled blankets and tritium breeders, high velocity helium jets for cooling plasma facing components, liquid metals flowing along the solid and through the porous metal walls facing the plasma, liquid metals and molten salts flowing through electrically insulated and non-insulated channels of blankets, and liquid metal heat pipes incorporated into the blankets and divertors for augmenting heat removal and achieving high thermal energy conversion efficiencies. The current fusion-to-thermal energy conversion technologies are, however, in an early stage of development and require reduced-activation, long life operation at high temperatures, resistance to plasma disruptions, and low fusion fuel retention materials, and innovative tritium breeding and heat removal concepts for building simple, reliable, safe, and efficient fusion energy technology.