Reactivity of metal-containing monomers 66. Hydrogenation of nitrotoluene derivatives in the presence of polymer-immobilized Pd nanoparticles

A new approach to the synthesis of immobilized catalysts of the mixed type was developed: frontal polymerization of metal-containing monomers in the presence of a highly dispersed inorganic support. The synthesis of the acrylamide complex of Pd^II nitrate on the SiO₂ surface followed by polymerization and reduction results in the formation of a polymer-inorganic composite with inclusions of Pd nanoparticles stabilized by the polymer matrix on the support surface. The study of the catalytic properties in the hydrogenation of nitrotoluene derivatives showed that the polymer-immobilized Pd nanoparticles on the inorganic support are efficient catalysts for the reduction of the nitrocompounds.     

Nanocomposite electrode materials based on poly(3,4-ethylenedioxythiophene) with incorporated gold and palladium: Preparation and morphology study

Chemical deposition of ultrafine gold and palladium particles into poly(3,4-ethylenedioxythiophene) matrix has yielded the metal-containing polymer composites. Their structure has been studied as affected by duration of reduced polymer immersion into the metal salts solution, and by concentration of the latter. Morphology features of the composite films (size and concentration of metal particles) have been elucidated by scanning and transmission electron microscopy. The mixed clusters have been formed predominantly in the course of preparation of bimetal composite films via sequential deposition of gold and palladium; the isolated palladium clusters nucleate slower due to the gold-palladium alloys formation. Longer deposition of the metals leads to increase in the nanoparticles size and their concentration in the composite. Properties of the prepared materials have been demonstrated using the model electrochemical reactions.     

配合物聚合反应研究──Ⅰ.以对氨基苯磺酸盐合成聚酰亚胺

以对氨基苯磺酸的二价金属配合物为原料合成了一系列主链上含金同元素（Ｃａ，Ｃｕ．Ｃｏ，Ｍｉ）的聚酰亚胺．以元素分析、ＩＲ和固体（１３）Ｃ－ＮＭＲ对其组成及结构进行了表征，通过ＴＧ－ＤＴＡ研究了其热性能，并讨论了含金属元素聚酰胺酸溶液的粘度与其中金属元素及其含量的关系     

The preparation by true liquid crystal templating of mesoporous silicates containing nanoparticulate metals

Mesostructured silicates containing metal nanoparticles have been synthesised via templating around a pre-formed, metal-containing mesophase using a non-ionic surfactant.     

含金属高聚物材料

综述含金属高聚物及其复合材料的制备方法，并简介这些材料所具有的导电，液晶，非线性光学等特殊性能及其应用前景。     

含金属纳米粒子的层层自组装及单壁碳纳米管的催化生长

利用层间的静电吸附作用，重氮树脂和不同种类的含金属纳米粒子被依次吸附到硅片表面形成层层自组装膜。通过改变自组装膜的层数可以控制纳米粒子在表面吸附的量，同时利用重氮树脂的光敏特性可以实现纳米粒子在表面的图案化排布。以这些纳米粒子为催化剂，研究了单壁碳纳米管在硅片表面的化学气相沉积生长。     

Epoxy Nanocomposites

The formation and physical properties of epoxy nanocomposites with carbon (nanotubes, graphene, and graphite), metal-containing, and aluminosilicate (montmorillonite and halloysite) fillers are considered. The mutual effect of both a matrix and nanoparticles on the composite structure is discussed. The role of the interfacial layer in the mechanical properties of nanocomposites is revealed. It is found that the concentration dependence of electrical and thermal conductivities of the composites is related to the percolation phenomenon.     

The reduction of gold nanoparticles in the surface layer of modified silica

Silicas with deposited hydridepolysiloxane layers were used for the in situ preparation of gold nanoparticles by the reduction of metal ions from a solution of chloroauric acid. The metal-containing silicas obtained were characterized by X-ray powder diffraction, transmission electron microscopy, and UV, IR, and laser correlation spectroscopy.     

Mechanical properties of epoxy composites based on silver nanoparticles formed in situ

The mechanical and thermomechanical properties of metal-containing epoxy composite films based on silver nanoparticles synthesized in situ are investigated. There is a nonmonotonic dependence of the mechanical properties on the concentration of silver myristate used as a precursor. It is found for the first time that the breaking strength and elastic modulus increase by a factor of 1.8–1.5 relative to those of the unmodified matrix at a small concentration of precursor nanoparticles (on the order of 0.1 wt %). DSC and thermomechanical studies reveal that the glass-transition temperature decreases slightly (by 5–6°C) as the precursor concentration is increased to 0.5 wt %, thereby suggesting a weak plasticization of the modified epoxy matrix. On the basis of the spectrophotometry data measured in the region of surface plasmon resonance of silver nanoparticles (420–425 nm) and SEM data, it is inferred that the in situ strengthening of an epoxy nanocomposite based on epoxy resin ED-20, triethylamine, and silver myristate is attained because silver nanoparticles smaller than 20 nm in size and having a narrow particle-size distribution are formed during curing.     

Self-assembling and size-selective synthesis of Ni and NiO nanoparticles embedded in ordered mesoporous carbon and polymer frameworks

We demonstrate the self-assembling and size-selective synthesis of uniform and highly dispersed Ni or NiO nanoparticles with diameters below 12 nm embedded in ordered mesoporous carbon or polymer frameworks. Self-assembly is induced by evaporation of the solvent from a mixture of metal-containing liquid crystalline (LC) mesophases of triblock copolymer and transition metal nitrate hydrate, and the carbon source is low-polymerized phenolic resol. Characterization by XRD, N(2) sorption isotherms, TEM, HRSEM, ICP-AES, TG, and XPS techniques has indicated an ordered 2D hexagonal mesostructure, high surface areas between 524 and 721 m(2) g(-1), uniform pore sizes of about 4.0 nm, large pore volumes ranging from 0.34 to 0.58 cm(3) g(-1), and metal contents ranging from 0.6 to 10.0 wt%. There is a high degree of dispersion, and a small size of nanoparticles throughout the whole framework, without aggregation outside of the pores due to the confinement effect of the mesoporous ordered matrix. The mesoporous solids show excellent adsorption properties for dyes and permit an easy magnetic separation procedure. This method is expected to be applicable to other mesoporous transition metal(oxide)-containing carbon catalysts.     

Catalytic fire retardant nanocomposites

In this paper the chemical activity of carbon nanotubes and polyhedral oligomeric silsesquioxane during thermal degradation and combustion of polymer nanocomposites is addressed. Indeed, polymer-nanofiller systems may exhibit chemical effects capable of thermal stabilisation of polymers as well as reduction of combustion rate and heat released, owing to catalytic effects induced by the nanofillers at high temperature.Carbon nanotubes in the presence of oxygen are shown to promote oxidative dehydrogenation in polyethylene with production of a stable surface layer of carbon char that provides an effective oxygen barrier effect. A similar action is performed by metal-containing polysilsesquioxanes dispersed in polypropylene.With either carbon nanotubes or metal POSS, partial carbonisation of the polymer matrix occurs during combustion, subtracting part of the organic polymer from combustion, targeting one of the major fire retardancy aim.     

Controlling the self-assembly structure of magnetic nanoparticles and amphiphilic block-copolymers: from micelles to vesicles

We report how to control the self-assembly of magnetic nanoparticles and a prototypical amphiphilic block-copolymer composed of poly(acrylic acid) and polystyrene (PAA-b-PS). Three distinct structures were obtained by controlling the solvent-nanoparticle and polymer-nanoparticle interactions: (1) polymersomes densely packed with nanoparticles (magneto-polymersomes), (2) core-shell type polymer assemblies where nanoparticles are radially arranged at the interface between the polymer core and the shell (magneto-core shell), and (3) polymer micelles where nanoparticles are homogeneously incorporated (magneto-micelles). Importantly, we show that the incorporation of nanoparticles drastically affects the self-assembly structure of block-copolymers by modifying the relative volume ratio between the hydrophobic block and the hydrophilic block. As a consequence, the self-assembly of micelle-forming block-copolymers typically produces magneto-polymersomes instead of magneto-micelles. On the other hand, vesicle-forming polymers tend to form magneto-micelles due to the solubilization of nanoparticles in polymer assemblies. The nanoparticle-polymer interaction also controls the nanoparticle arrangement in the polymer matrix. In N,N-dimethylformamide (DMF) where PS is not well-solvated, nanoparticles segregate from PS and form unique radial assemblies. In tetrahydrofuran (THF), which is a good solvent for both nanoparticles and PS, nanoparticles are homogeneously distributed in the polymer matrix. Furthermore, we demonstrated that the morphology of nanoparticle-encapsulating polymer assemblies significantly affects their magnetic relaxation properties, emphasizing the importance of the self-assembly structure and nanoparticle arrangement as well as the size of the assemblies.     

Genesis of nanostructured, magnetically tunable ceramics from the pyrolysis of cross-linked polyferrocenylsilane networks and formation of shaped macroscopic objects and micron scale patterns by micromolding inside silicon wafers

The ability to form molded or patterned metal-containing ceramics with tunable properties is desirable for many applications. In this paper we describe the evolution of a ceramic from a metal-containing polymer in which the variation of pyrolysis conditions facilitates control of ceramic structure and composition, influencing magnetic and mechanical properties. We have found that pyrolysis under nitrogen of a well-characterized cross-linked polyferrocenylsilane network derived from the ring-opening polymerization (ROP) of a spirocyclic [1]ferrocenophane precursor gives shaped macroscopic magnetic ceramics consisting of alpha-Fe nanoparticles embedded in a SiC/C/Si(3)N(4) matrix in greater than 90% yield up to 1000 degrees C. Variation of the pyrolysis temperature and time permitted control over the nucleation and growth of alpha-Fe particles, which ranged in size from around 15 to 700 A, and the crystallization of the surrounding matrix. The ceramics contained smaller alpha-Fe particles when prepared at temperatures lower than 900 degrees C and displayed superparamagnetic behavior, whereas the materials prepared at 1000 degrees C contained larger alpha-Fe particles and were ferromagnetic. This flexibility may be useful for particular materials applications. In addition, the composition of the ceramic was altered by changing the pyrolysis atmosphere to argon, which yielded ceramics that contain Fe(3)Si(5). The ceramics have been characterized by a combination of physical techniques, including powder X-ray diffraction, TEM, reflectance UV-vis/near-IR spectroscopy, elemental analysis, XPS, SQUID magnetometry, M?ssbauer spectroscopy, nanoindentation, and SEM. Micromolding of the spirocyclic [1]ferrocenophane precursor within soft lithographically patterned channels housed inside silicon wafers followed by thermal ROP and pyrolysis enabled the formation of predetermined micron scale designs of the magnetic ceramic.     

Synthesis and properties of new carbazole-containing metallopolymers with transannular polyconjugation in the backbone

New metal-containing polymers, poly(salicylidene azomethines) containing metal atoms (Co, Ni, Cu) in the backbone, were synthesized from aromatic carbazolediamine derivatives. It was found that the polymers with a decyl substituent in the carbazole fragment are soluble in organic solvents (chloroform, methanol, DMSO, DMF) and exhibit film-forming and semiconductor properties. IR and NMR spectroscopy was used to show that the semiconductor properties of the new polymers are associated with the presence in the polymer backbone of transannular polyconjugation zones formed by intramolecular donor?acceptor interactions of the metal and nitrogen valence shells.     

高分子/单链高分子纳米粒子复合体系中的界面性质

高分子与纳米粒子复合是改善高分子材料性能的有效途径.近20年来关于高分子/纳米粒子复合物的研究引起了学术界广泛的兴趣.然而由于此类体系中的影响因素复杂,虽然学者们在相关材料性能的研究方面取得了重要进展,但是相关理论的发展却相对滞后,其中一个重要原因是实验上表征手段的缺失,导致对体系中纳米粒子与本体高分子链相互作用规律的认识(尤其是两者界面性质的认识)不够.本文总结和阐述了我们近几年利用分子动力学模拟技术研究高分子/单链高分子纳米粒子复合体系的主要结果,并围绕此类复合体系中的界面结构及动力学性质,讨论并总结了纳米粒子对本体高分子链的作用范围及影响规律,指出单链纳米粒子对熔体链的作用范围与纳米粒子的自身尺寸相当,而与熔体高分子链的分子量没有直接的关系.该结论将为纳米复合体系高分子理论的发展提供重要参考.     

Conducting metallopolymers: the roles of molecular architecture and redox matching

Recent reports of highly conductive metallopolymers are reviewed. This literature is classified into one of two categories (inner or outer sphere) depending on the mode of interaction between the transition metal centers with each other and the conducting polymer backbone. The critical nature of charge transport is discussed in the context of the relative energies of the organic polymer-based and metal-centered redox processes. Also included are recent advances in the development of functional materials based on metal-containing conducting polymers.     

含烷氧基钕共聚物的合成及其光学性质

用三烷氧基钕与顺丁烯二酸酐反应合成10种与MMA有良好相容性的含烷氧基钕单体,将其与MMA共聚制得10种含烷氧基钕共聚物。研究了共聚物材料的光学性质及其影响因素。表明含烷氧基钕共聚物较PMMA有较高透光率和折光率,折光率随钕含量增加而线性增大,且具有Nd³⁺离子特征的光选择吸收性,是一类性能优异的新型光学塑料。     

Formation of metal-containing nanoparticles in polymer matrix. Computer simulation of clusterization kinetics during the solid-phase thermal decomposition of metal-containing precursors

The scheme of computer simulation of the dynamics of the formation of metal-containing clusters in a polymer matrix during the solid-phase thermolysis of corresponding precursors is developed. The kinetics of particle nucleation and growth is studied within the framework of the model of diffusion-limited aggregation by the combined marching and Monte Carlo methods. Polymer media with different structural organization such as isotropic (globular) and anisotropic (layered and fibrillar) media are considered. Deterministic algorithms of the model are the decomposition of reactive metal-containing groups of a polymer, solid-phase diffusion of particles, and cluster dissociation. The proposed scheme makes it possible to visualize the process of cluster formation.61st communication from Preparation and Reactivity of Metal-Containing Monomers series. For 60th communication see [1].Translated from Kolloidnyi Zhurnal, Vol. 67, No. 1, 2005, pp. 70–78. Original Russian Text Copyright © 2005 by A.S. Rozenberg, A.A. Rozenberg, Dzardimalieva, Pomogailo.     

Enhancing the ionic conductivity in a composite polymer electrolyte with ceramic nanoparticles anchored to charged polymer brushes

Polymer electrolytes a re essential for next-gene ration lithium batteries because of their excellent safety record.However,low ionic conductivity is the main obstacle restricting their commercial application.Composites with nanoparticles are a promising route to overcome this obstacle.In this work,lithium polystyrene sulfonate brushes(LiPSS)is anchored to silicon dioxide nanoparticles with chemical bonding using atom transfer radial polymerization(SI-ATRP).The composite polymer electrolytes are made by mixing vinylene carbonate and nanoparticles via a facile in situ polymerization process.The ionic conductivity of composite polymer electrolytes is improved to 7.2×10^-4 S/cm at room temperature,which is attributed to the low degree of crystallinity of polymer electrolyte and the fast ion transport on the surfaces of polymer brush layers that act as a conductive network.The composite polymer electrolytes show a wide electrochemical window of approximately 4.5 V vs.Li^+/Li and excellent cycling performance retention of approximately 95%after 100 cycles at ambient temperature.The results also prove that surface groups of ceramic na noparticles are an important way to increase the electrochemical properties of composite polymer electrolytes.     

Controlled nanoparticle assembly by dewetting of charged polymer solutions

In this paper, we present an alternative approach for controlled nanoparticle organization on a solid substrate by applying dewetting patterns of charged polymer solutions as a templating system. Thin films of charged polymer solutions dewet a solid substrate to form complex dewetting patterns that depend on the polymer charge density. These patterns, ranging from polygonal networks to elongated structures that are stabilized by viscous forces during dewetting, serve as potential templates for two-dimensional nanoparticle organization on a solid substrate. Thus, while nanoparticles dried in pure water undergo self-assembly to form close-packed arrays, addition of charged polymer in the dispersion leads to the formation of open structures that are directed by the dewetting patterns of the polymer solution. In this study, we focus on the application of elongated structures resulting from dewetting of high-charge-density polymer solutions to align nanoparticles of silica and gold into long chains that are several micrometers in length. The particle ordering process is a two-step mechanism: an initial confinement of the nanoparticles in the dewetting structures and self-assembly of the particles within these structures upon further drying by lateral capillary attractions.