高分子自组装掩膜的制备

利用高分子共混物的微相分离和自组装原理,采用溶液共混和旋转涂膜的方法制得聚苯乙烯/聚甲基丙烯酸甲酯(PS/PMMA)高分子共混物薄膜,对薄膜经过再加工得到具有纳米微孔的PMMA薄膜,研究了对溶液进行超声处理的时间、PS/PMMA共混物溶液浓度、旋涂转速和试片表面对掩膜形貌的影响。以此PMMA薄膜为掩膜对GaP表面进行湿法腐蚀,得到一种蜂窝状的表面微结构,它能使发光二极管(LED)的光功率平均提高18%。     

静电自组装功能性纳米复合膜的研究进展

通过静电相互作用可自组装形成功能性纳米复合膜.近年来,这一技术发展十分迅速,并且得到了广泛的应用.综述了静电自组装成膜的机理、制备、表征的最新研究进展.     

层层自组装技术制备新型功能高分子材料研究进展

层层自组装技术是一种新型的功能高分子材料制备方法,尤其是在薄膜材料制备方面有着广泛的应用,该技术能在分子水平控制成膜材料的层数、厚度及其结构。介绍了层层自组装技术在医药领域、医用材料领域、食品领域、纺织行业、传感器、阻燃材料领域、超疏水材料和微胶囊制备中的应用情况。随着科技的进步,层层自组装技术的应用领域将不断拓宽。     

静电自组装纳米复合膜及其应用

对静电自组装方法制备的纳米复合膜的组成,结构及其在发光二极管、高容量电池、等方面的潜在应用进行了综述。     

金纳米棒(丝)自组装的研究进展

主要评述了金纳米棒自组装的最新研究进展.将金纳米棒组装为各种尺度的有序结构会产生更优异的整体协同性质,这对以金纳米棒为基础而构筑的微纳米器件有着重要的意义.具体评述了模板诱导的金纳米棒的自组装、表面张力诱导的金纳米棒的自组装及应用.     

《自然-材料学》：自组装纳米结构性能超越骨骼

美国Sandia国家实验室、新墨西哥大学、凯斯西储大学以及普林斯顿大学的科学家最近发现，自组装纳米结构能够超越自然界的“鬼斧神工”，在更加多孔的同时，又不会过于降低强度。相关论文发表在6月的《自然-材料学》上。进项该项研究的是项目负责人Jeff Brinker表示，“微电子学和膜技术领域往往需要既多孔又坚固的材料，     

高分子自组装制备多壁纳米炭管(英文)

通过将聚硅氮烷和聚乙烯吡咯烷酮在一定条件下混合,经过分子聚合及惰性气体保护下高温热处理,在SiCN陶瓷基体表面生长短的多壁碳纳米管。所制备的碳纳米管长度短,在～500 nm范围,直径在～30 nm,并且具有完整的管状结构。多壁纳米炭管形成机理是聚乙烯吡咯烷酮在溶液中自组装形成的高分子管状结构,再经高温炭化而成。     

嵌段共聚物自组装模板--构造纳米结构的一种新方法

纳米结构的构造在整个纳米科技中有着特殊重要的意义．如何低成本、大规模地实现纳米结构材料的控制合成与组装一直是纳米加工中的热点问题．高分子嵌段共聚物分子结构独特,包含着热力学不相容的不同高分子嵌段,并由化学键相连．通过控制外界条件,嵌段共聚物可以自组装成高度规则的超分子结构,特征尺寸为10nln～100nm．以嵌段共聚物膜自组装相分离图案为模板,或把这种图案复制到其它材料上,通过刻蚀等技术可以制备纳米结构模板,再经纳米铸造得到相应结构的纳米材料和纳米器件,文中主要介绍嵌段共聚物自组装模板的原理、模板图案的调控方法和模板应用,并详细阐述了各自的发展状况。     

分子自组装型水性丙烯酸改性环氧聚酯纳米乳液的合成

利用分子自组装技术采用两嵌段聚合物或共聚物制备出了水性丙烯酸改性环氧聚酯纳米乳液.合成出的聚合物纳米乳液的粒径随反应温度的升高而逐渐减小,当温度升高到100℃时,聚合物纳米乳液的粒径随温度升高逐渐增大.乳液粒径随引发剂浓度的升高和水含量的升高而逐渐减小.研究了相对于某一分散介质(例如水),这些聚合物形成球状胶束(纳米尺度内,50～90nm),在这种胶束中极性链段构成胶束的壳,而非极性链段构成胶束的核,所以乳液体系得以分散稳定.该乳液在正相反相的转变过程中经过一种特殊的双连续结构,在连续的转相过程中体系始终保持各向同性.该纳米级聚合物乳液平均粒径尺寸可达72nm.可用做水性工业漆的成膜材料.     

自组装生物材料

21世纪的许多科学活动都是在化学与生物学,化学与材料科学的界面上进行的,因此将生物学运用于其他学科而衍生出来的方法将大大促进科学工作的发展。自组装材料被认为是21世纪材料科学与工程最重要的领域之一。自组装是一种普遍存在于生命体系中的现象,是生命最本质的内容之一。大量复杂的、具有生物学功能的大分子系统(蛋白质、核酸、生物膜、脂质体等)正是通过分子自组装形成的。例如生物合成的蛋白质就是通过各亚基的分子自组装而形成的具有特定功能的集合体。具体来说,自组装过程是人类不主动介入的过程,其中的原子、分子、分子团和组件…     

自组装法制备聚合物纳米复合膜的新进展

介绍了自组装法制备聚合物纳米复合膜的几种最新技术;化学吸附法、分子沉积法、旋涂法。这些方法操作简单,膜的结构稳定性较高,利用它们可以制备各种功能化的聚合物纳米复合膜,从而实现薄膜的光、电、磁、非线性光学等的功能化。由此,这些方法受到国内外的广泛重视。     

分子自组装体系的影响因素及其在纳米材料中的应用

介绍了分子自组装体系的影响因素以及分子自组装技术在纳米材料制备方面的应用,并对聚合物自组装体系及研究进展作了综述.     

纳滤膜纯化球状大分子的可行性研究

分析了球状大分子合成中的目标产物难分离难纯化的特点,采用纳滤膜分离技术纯化新型纳米材料——球状大分子;通过HPLC和元素分析测试了纯化前后的纯度,证明了纳滤膜是可以提高目标球状大分子的纯度;孔径较大的NF1膜有利于乙二胺的透过,其纯度提高较大,而孔径较小的NF2膜对乙二胺的透过能力下降,所以纯度提高较小。     

An energetic model for macromolecules unfolding in stretching experiments

We propose a simple approach, based on the minimization of the total (entropic plus unfolding) energy of a two-state system, to describe the unfolding of multi-domain macromolecules (proteins, silks, polysaccharides, nanopolymers). The model is fully analytical and enlightens the role of the different energetic components regulating the unfolding evolution. As an explicit example, we compare the analytical results with a titin atomic force microscopy stretch-induced unfolding experiment showing the ability of the model to quantitatively reproduce the experimental behaviour. In the thermodynamic limit, the sawtooth force–elongation unfolding curve degenerates to a constant force unfolding plateau.     

纳米ZnO的研究及其进展

纳米ZnO的许多优异性能使其成为人们研究的热点并得到广泛的应用。随着ZnO颗粒尺度的不断减小，其量子限域效应越来越明显，观察到电荷载流子，声子，光子的局域化效应；表面、界面态对其性质影响逐渐明显，通过表面修饰和置入多孔及束管等束缚结构，可有效增强ZnO紫外（一个量级）或可见光区（1－2个量级）的发射强度；并使ZnO的电导率，磁化率有很大提高，纳米ZnO与其他材料的复合体系能得到一些新的功能材料。纳米ZnO的自组织行为，使人们可以获得许多形态各异，特殊用途的纳米材料及器件。本文综述了近年来纳米ZnO的研究新动态。     

J-Aggregation of an anionic oxacarbocyanine in electrostatically self-assembled multilayers

Unlike in water solution, interaction of the anionic oxacarbocyanine E (structure in Fig. 1) with three polycations electrostatically adsorbed on a quartz substrate results in an extensive J aggregation of the dye. J-aggregates grow on the film surface beyond charge saturation, making possible the formation of alternately adsorbed polycation/E multilayers. UV-visible absorption and fluorescence spectra have revealed that, although less ordered than in solution, J aggregates are dominant in dry films. They are characterized by some heterogeneity and exhibit a reorganization dynamics in the presence of water. Polarized absorption has shown that the J-band transition-dipole moments lie preferentially parallel to the film plane, thus suggesting a plausible arrangement for a bidimensional brickwork aggregate. An exploration of the effects of various preparation variables (solution concentrations and ionic strengths, dipping times, film drying speed, polycation nature and molecular weight) has afforded some insight into the processes involved in polycation/J-aggregate multilayer formation.     

Recent developments in anionic polymerization

The past year witnessed very significant advances in the living anionic polymerization of (meth)acrylate monomers, particularly in hydrocarbons at or below 0°C. Block polymerization of alkyl methacrylates with primary alkyl acrylates, although somewhat improved, remains a challenge. Anionic polymerization of styrene, diene and its derivatives was carried out with the aim of synthesizing functional polymers and block copolymers of various architectures. There has been a trend towards combining different living techniques in order to design polymers of unique architectures and properties     

Recent developments in explosive welding

Explosion welding (EXW) is one of the joining methods consisting of a solid state welding process in which controlled explosive detonation on the surface of a metal. During the collision, a high velocity jet is produced to remove away the impurities on the metal surfaces. Flyer plate collides with base plate resulting in a bonding at the interface of metals. The metal plates are joined at an internal point under the influence of a very high pressure and causes considerable local plastic deformation at the interface in which metallurgical bonding occurs in nature and even stronger than the parent metals. Similar and dissimilar materials can be joined by explosive welding. In this paper, after detection the theories of welding and wave formation, experimental research and numerical studies on explosive welding are reviewed for the last four decades. Also, future developments in explosive welding are predicted and criticized in an outlook.     

ZnO基纳米电子材料研究进展

纳米ZnO的许多优异性能使其成为人们研究的热点并得到广泛应用.ZnO是一种同时具有半导体和压电双重特性的材料.运用不同的工艺,目前已生长出纳米线(棒)、纳米带、纳米环、四角形纳米结构、纳米笼、纳米螺旋等多种特殊形态的纳米ZnO.由这些许多独特的形态,可以看出纳米ZnO是纳米材料家族中可以生长出的结构最多样的成员之一.这些纳米结构在光电、传导、传感以及生化等不同领域有很多潜在的新颖的应用前景.     

Recent developments in detector research

Recently developed methods of cryogenic particle detection and potential applications will be introduced. The main part of this article focuses on our experimental results on two different approaches of detecting nuclear radiation with superconducting tunnel junctions. The best energy resolution is obtained when the junction itself serves as absorber. Using Sn/SnO_x/Sn tunnel junctions we obtained an energy resolution of about 90 eV for 6 keV X-rays up to now. The processes limiting the resolution of the present devices will be discussed. Larger absorber masses and position resolution are realized by an entirely new type of particle detector based on the detection of nonthermal phonons which are generated by the absorption of radiation within a single-crystalline absorber of dielectric material. We report on experimental tests of a detector composed of a silicon single crystal (size: 10 × 20 × 3 mm³) and of an array of superconducting Al/Al₂O₃/Al tunnel junctions evaporated onto the surface of the crystal, serving as phonon detectors. Pulse height analysis and the investigation of time differences between pulse onsets in different junctions are shown to yield information about the absorption point of -particles.