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Particle Arrays (particle + array)

Distribution by Scientific Domains

Polymers and Materials Science	88%

Distribution within Polymers and Materials Science

General & Introductory Materials Science	62%
Polymer Science & Technology General	37%

Selected Abstracts

Fabrication of a Metal Particle Array Based on a Self-Assembled Template from a Two-Armed Polymer,

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 8 2003
Jun Fu
Abstract A two-armed polymer with a crown ether core self-assembles to produce macroporous films with pores perpendicularly reaching through the film down to the substrate. A possible assembling mechanism is discussed. The pore size can be conveniently adjusted by changing the solution concentration. These through-hole macroporous films provide a template for fabricating an array of Cu nanoparticle aggregates. [source]

Multifaceted and Nanobored Particle Arrays Sculpted Using Colloidal Lithography,

ADVANCED FUNCTIONAL MATERIALS, Issue 1 2006
D.-G. Choi
Abstract A novel method of fabricating multifaceted and nanobored particle arrays via colloidal lithography using colloidal-crystal layers as masks for anisotropic reactive-ion etching (RIE) is reported. The shape of the sculpted particles is dependent on the crystal orientation relative to the etchant flow, the number of colloidal layers, the RIE conditions, and the matrix (or mask) structure in colloidal lithography. Arrays of non-spherical particles with sculpted shapes, which to date could not otherwise be produced, are fabricated using a tilted anisotropic RIE process and the layer-by-layer growth of a colloidal mask. These non-spherical particles and their ordered arrays can be used for antireflection surfaces, biosensors, and nanopatterning masks, as well as non-spherical building blocks for novel colloidal crystals. In addition, polymeric particles with patterned holes of controlled depths obtained by the present method can be applied to the fabrication of functional composite particles. [source]

Suppression of Ni4Ti3 Precipitation by Grain Size Refinement in Ni-Rich NiTi Shape Memory Alloys,

ADVANCED ENGINEERING MATERIALS, Issue 8 2010
Egor A. Prokofiev
Severe plastic deformation (SPD) processes, such as equal channel angular pressing (ECAP) and high pressure torsion (HPT), are successfully employed to produce ultra fine grain (UFG) and nanocrystalline (NC) microstructures in a Ti,50.7,at% Ni shape memory alloy. The effect of grain size on subsequent Ni-rich particle precipitation during annealing is investigated by transmission electron microscopy (TEM), selected area electron diffraction (SAD, SAED), and X-ray diffraction (XRD). It is observed that Ni4Ti3 precipitation is suppressed in grains of cross-sectional equivalent diameter below approximately 150,nm, and that particle coarsening is inhibited by very fine grain sizes. The results suggest that fine grain sizes impede precipitation processes by disrupting the formation of self-accommodating particle arrays and that the arrays locally compensate for coherency strains during nucleation and growth. [source]

Silver Nanoparticles with Controlled Dispersity and Their Assembly into Superstructures

ADVANCED ENGINEERING MATERIALS, Issue 5 2010
Karsten Moh
In this paper we report on the influence of particle size distribution, particle substrate interaction, and drying behavior on the self-assembly process using ligand stabilized silver particles. Two-dimensional particle arrays were characterized using transmission electron microscopy and extensive image analysis. The formation of such structures was observed in situ using an environmental scanning electron microscope in WET-STEM mode. The results confirm that a small particle size distribution is crucial for the formation of regular particle patterns with long range order, but also the particle substrate interaction and the particle density have an influence on the degree of ordering. Additionally, we find that separated binary particle assemblies keep the orientation of their two-dimensional hexagonal lattices over alternating domains of small and big particles. This is probably enabled due to the formation of dislocations and a small change of the course of the lattice lines within the respective boundary. [source]

Multifaceted and Nanobored Particle Arrays Sculpted Using Colloidal Lithography,

Mesoscopic Au "Meatball" Particles,

ADVANCED MATERIALS, Issue 4 2008
H. Wang
Sub-micrometer meatball-like Au particles provide a very interesting mesoscopic regime in which their optical responses are determined by both the mesoscopic size and the particle's nanoscale surface roughness. The unique optical properties of these mesoscopic particles and particle arrays hold great potential in chemical sensing and spectroscopic applications. [source]

Structural estimation of particle arrays at air,water interface based on silica particles with well-defined and highly grafted poly(methyl methacrylate)

POLYMER ENGINEERING & SCIENCE, Issue 6 2010
Jung-Min Moon
Silica nanoparticles with well-defined, highly grafted dense poly(methyl methacrylate) (MMA) were prepared by surface-initiated activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP) of methyl methacrylate with an initiator-fixed silica particle in the presence of air. Two different polymerizations of MMA were carried out under the same conditions using tris[2-(dimethylamino)ethyl]amine (Me6TREN) and N,N,N,,N,,N,-pentamethyldiethylene-triamine (PMDETA) as the ligand, respectively. In the CuCl2/PMDETA system, polymerization appeared to be more controlled with a lower polydisperisty compared with the CuCl2/Me6TREN system. The monolayer of these particles was formed at the air,water interface using Langmuir-Blodgett (LB) technique. Multilayers of the particles were fabricated by repetition of LB depositing. A surface pressure,area (,,A) measurement and SEM observation were used to characterize the particle arrays. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers [source]

Hydrodynamic Cell Model: General Formulation and Comparative Analysis of Different Approaches

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2007
Emiliy K. Zholkovskiy
Abstract This paper is concerned with the Cell Model method of addressing hydrodynamic flow through system of solid particles. The starting point of the analysis is the general problem formulation intended for describing a pressure driven flow through a diaphragm which can be considered as a set of representative cells having arbitrary shape and containing any number of particles. Using the general problem formulation, the hydrodynamic field inside an individual representative cell is interrelated with the applied pressure difference and the external flow velocity. To this end, four relationships containing integrals over the outer boundary of a representative cell are derived in the paper. Assuming that the representative cell is a sphere containing a single particle in the centre, the derived general relationships are transformed into outer cell boundary conditions employed in the literature by different authors. The general number of the obtained outer boundary conditions is more than the required number. Accordingly, by choosing different sets of the outer boundary conditions, different models are considered and compared with each other and with the results obtained by others for regular particle arrays. The common and different features of the hydrodynamic and electrodynamic versions of the Cell Model approaches are analyzed. Finally, it is discussed which version of the cell model gives the best approximation while describing pressure and electrically driven flows through a diaphragm and sedimentation of particles. On s'intéresse dans cet article à la méthode du Modèle de Cellules pour traiter l'écoulement à travers un système de particules solides. Le point de départ de l'analyse consiste à formuler le problème général dans le but de décrire un écoulement sous pression dans un diaphragme qui peut être considéré comme un ensemble de cellules représentatives de forme arbitraire et contenant un nombre quelconque de particules. À l'aide de cette formulation générale du problème, l'hydrodynamique dans une cellule représentative donnée est reliée à la différence de pression appliquée et à la vitesse d'écoulement externe. À cette fin, quatre relations contenant des intégrales sur la frontière d'une cellule représentative sont établies dans cette étude. Si l'on suppose que la cellule représentative est une sphère contenant une particule unique en son centre, les relations générales calculées peuvent être transformées en conditions à la frontière des cellules semblables à celles employées dans la littérature scientifique par différents auteurs. Le nombre général de conditions limites obtenues dépasse le nombre requis. Par conséquent, en choisissant différents ensembles de conditions limites, différents modèles sont considérés et comparés entre eux ainsi qu'avec les résultats obtenus pour des arrangements réguliers de particules. Les caractéristiques des versions hydrodynamiques et électrodynamiques des approches du Modèle de Cellules sont analysées. Finalement, on examine quelle version de modèle de cellule donne la meilleure approximation des écoulements sous pression et des écoulements électrodynamiques à travers un diaphragme et pour la sédimentation des particules. [source]