[PDF] Anisotropic Self Assembly Of Spherical Polymer Grafted Nanoparticles eBook

Author :
Publisher :
Page : 7 pages
File Size : 34,27 MB
Release : 2009
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ISBN :

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It is easy to understand the self-assembly of particles with anisotropic shapes or interactions (for example, cobalt nanoparticles or proteins) into highly extended structures. However, there is no experimentally established strategy for creating a range of anisotropic structures from common spherical nanoparticles. We demonstrate that spherical nanoparticles uniformly grafted with macromolecules ('nanoparticle amphiphiles') robustly self-assemble into a variety of anisotropic superstructures when they are dispersed in the corresponding homopolymer matrix. Theory and simulations suggest that this self-assembly reflects a balance between the energy gain when particle cores approach and the entropy of distorting the grafted polymers. The effectively directional nature of the particle interactions is thus a many-body emergent property. Our experiments demonstrate that this approach to nanoparticle self-assembly enables considerable control for the creation of polymer nanocomposites with enhanced mechanical properties. Grafted nanoparticles are thus versatile building blocks for creating tunable and functional particle superstructures with significant practical applications.

Author : Tsung-Yeh Tang
Publisher :
Page : 156 pages
File Size : 49,72 MB
Release : 2019
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ISBN :

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Polymer-nanoparticle composites have attracted considerable interest over the past few decades. While many traditional applications of composites require the nanoparticles (NPs) to remain well dispersed within the polymer matrix, some of the newer proposed applications rely on higher-order organization of NPs. Self-assembly provides a powerful bottom-up approach for organizing nanoparticles in a highly parallelized fashion. However, directing nanoparticles to self-assemble into anisotropic architectures more complex than the isotropic, close-packed structures or random aggregates observed under equilibrium or non-equilibrium conditions is highly challenging. In this dissertation, I will demonstrate how we have used molecular dynamics simulations to investigate and propose new polymer-mediated strategies for assembling spherical NPs into anisotropic, and often unique, configurations. We first investigated the underlying basis for anisotropic interactions between spherical NPs uniformly grafted with polymer chains, which were recently shown to assemble into anisotropic phases like strings and sheets. The anisotropy was shown to arise from the expulsion of polymer grafts between two contacting NPs, which led to anisotropic graft-mediated steric repulsion felt by a third approaching NP. Our computed phase diagram for formation of isotropic versus anisotropic 3-particle clusters agreed qualitatively with that obtained experimentally for larger aggregates of NPs. Next, we proposed a new strategy for assembling spherical nanoparticles into unique, anisotropic architectures in a polymer matrix. The approach takes advantage of the interfacial tension between two mutually immiscible polymers forming a bilayer to trap NPs within two-dimensional planes parallel to the interface. We demonstrated both trapping NPs at tunable distances from the interface and assembling them into a variety of unconventional nanostructures. We also developed a theoretical model to predict the preferred positions and free energies of NPs. Lastly, we studied the dynamics of polymer-grafted gold nanoparticles loaded into polymer melts. Under certain annealing conditions, the diffusion is one-dimensional and related to the direction of heat flow during annealing and is associated with an dynamic alignment of the host polymer chains. We used molecular dynamics simulations to investigate a single gold nanoparticle diffusing in a partially aligned polymer network which semi-quantitatively reproduce the experimental results to a remarkable degree.

Author : Xiaoteng Wang
Publisher :
Page : 172 pages
File Size : 20,88 MB
Release : 2019
Category : Nanoimprint lithography
ISBN :

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Controlled dispersion and distribution of functional nanoparticles (NPs) in polymer matrix is prerequisite for improved properties of the composite materials. How to control the distribution of NPs in a facile manner remains to be a recurring challenge in the applications of polymer nanocomposites (PNCs). Surface functionalization of NPs with polymer brushes has emerged as an effective and versatile platform of tuning the interactions between the nanoparticles and the polymer hosts, allowing their integration into polymer nanocomposites. The current work aims to understand the phase behaviors of polymer-grafted nanoparticles (PGNPs) in polymer thin films and further control the spatial distribution of PGNPs through the interactions between the grafted and matrix polymer chains. In particular, polystyrene-grafted titanium dioxide nanoparticles (PS-TiO2) embedded in polystyrene (PS) thin film matrices having an initial film thickness h0 » 90 nm were investigated, where fluctuations in the grafting brush layer enables the formation of self-assembled PGNP clustering structures. Nanoimprinting directed lateral organization of the PGNP clusters in polymer thin films via topographically soft-pattern confinement was demonstrated. The PGNP clusters segregate to thicker film regions where they are less confined during thermal annealing. The partitioning of the PGNP clusters to the patterned regions was quantified by introducing the cluster partition coefficient Kc. It shows that the highly selective segregation of the clusters was driven by entropic driving forces while the film surface homogenization and shape transition of the clusters were induced by geometrical confinement of the nanopatterning. Simultaneously, the stability of the low molecular weight PS thin films is greatly enhanced against dewetting by the addition of PGNPs. The extent of the dewetting suppression depends on the PGNP concentration and can also be altered by nanopatterning. This form of soft pattern-directed self-assembly may boost colligative properties and provide enhanced and anisotropic optical such as UV-Vis, electronic and other material properties associated with organized NP clusters into precise large-scale patterns. With better understanding of the chemically identical blend systems, we further extend our model study to other PGNP/polymer blends where enthalpic interactions also participate in the phase behavior. The hybrid blend system composed of polystyrene-grafted silica nanoparticles in a poly (vinyl methyl ether) (PS-SiO2/PVME) blend thin film (≈100 nm) was studied where the brush and matrix polymers exhibit LCST type of phase behavior. Phase separation between the polymer-grafted nanoparticles (PGNPs) and matrix polymer occurs at a temperature ≈ 40° C lower than the LCST of classic binary linear PS/PVME polymer blends. Spatially organized PGNP domain structures on submicrometer scale were illustrated by introducing the symmetry-breaking soft elastomer pattern. Selective partition of the nanoparticles in both one-phase and two-phase regions can be obtained via nanoimprinting. Thermal cycling of the composite film through the critical temperature allows for thermodynamically reversible formation and dissolution of PGNP-rich domain structures. This nanoimprinting guided assembly of PGNPs in polymer nanocomposites would open pathways of novel hybrid materials for many technological applications such as responsive materials.

Author : Dwaipayan Chakrabarti
Publisher : Elsevier
Page : 184 pages
File Size : 17,37 MB
Release : 2019-04-25
Category : Science
ISBN : 0081023030

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Self-assembly of Nano- and Micro-structured Materials Using Colloidal Engineering, Volume 12, covers the recent breakthroughs in the design and manufacture of functional colloids at the micro- and nanoscale level. In addition, it provides analyses on how these functionalities can be exploited to develop self-assembly pathways towards nano- and micro-structured materials. As we seek increasingly complex functions for colloidal superstructures, in silico design will play a critical role in guiding experimental fabrication by reducing the element of trial-and-error that would otherwise be involved. In addition to novel experimental approaches, recent developments in computational modelling are also presented, along with an overview of the arsenal of designing tools that are available to the modern materials scientist. Focuses on promoting feedback between experiment, theory and computation in this cross-disciplinary research area Shows how colloid science plays a crucial role in the bottom-up fabrication of nanostructured materials Presents recent developments in computational modelling

Author : Ivan Coluzza
Publisher : Springer
Page : 139 pages
File Size : 43,76 MB
Release : 2018-03-23
Category : Medical
ISBN : 331971578X

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This book provides in-depth insights into assembling dynamics of proteins, DNA and other nanoparticles. The applications of basic knowledge in the development of artificial self-assembling systems will be discussed and state of the art methodology in the field will be presented.This interdisciplinary work brings together aspects of different fields of expertise such as Biology, Physics and Material Sciences and is intended for researchers, professors and graduate students interested in the design of self-assembling materials.

Author :
Publisher : Elsevier
Page : 292 pages
File Size : 13,8 MB
Release : 2018-11-20
Category : Science
ISBN : 0128139358

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Nano-sized Multifunctional Materials: Synthesis, Properties and Applications explores how materials can be down-scaled to nanometer-size in order to tailor and control properties. These advanced, low-dimensional materials, ranging from quantum dots and nanoparticles, to ultra-thin films develop multifunctional properties. As well as demonstrating how down-scaling to nano-size can make materials multifunctional, chapters also show how this technology can be applied in electronics, medicine, energy and in the environment. This fresh approach in materials research will provide a valuable resource for materials scientists, materials engineers, chemists, physicists and bioengineers who want to learn more on the special properties of nano-sized materials. Outlines the major synthesis chemical process and problems of advanced nanomaterials Shows how multifunctional nanomaterials can be practically used in biomedical area, nanomedicine, and in the treatment of pollutants Demonstrates how the properties of a variety of materials can be engineered by downscaling them to nano size

Author : Sanjay Mavinkere Rangappa
Publisher : Woodhead Publishing
Page : 552 pages
File Size : 21,54 MB
Release : 2022-07-15
Category : Technology & Engineering
ISBN : 0323853293

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Nanoparticle-Based Polymer Composites discusses recent advancements on the synthesis, processing, characterization and applications of this new class of hybrid materials. Chapters cover recycling and lifecycle assessment, with contributions from leading researchers in industry, academics, the government and private research institutes from across the globe. As nanoparticle-based polymer composites are now replacing traditional polymer composites in a broad range of applications such as fuel cells, electronic and biomedical devices, this book presents the latest advancements in the field. Studies have shown that incorporating metal nanoparticles in polymer matrices can improve their mechanical, thermal, electrical and barrier properties. The unique combination of these properties makes this new class of materials suitable for a broad range of different and advanced applications. Features recent advancements on the synthesis, processing and characterization of nanoparticle-based polymer composites Discusses recycling and lifecycle assessment Highly application-orientated, with contributions from leading international researchers in industry, academia, the government and private research institutes

Author : Wolfgang Knoll
Publisher : John Wiley & Sons
Page : 1107 pages
File Size : 46,79 MB
Release : 2013-02-12
Category : Science
ISBN : 3527638490

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Very thin film materials have emerged as a highly interesting and useful quasi 2D-state functionality. They have given rise to numerous applications ranging from protective and smart coatings to electronics, sensors and display technology as well as serving biological, analytical and medical purposes. The tailoring of polymer film properties and functions has become a major research field. As opposed to the traditional treatise on polymer and resin-based coatings, this one-stop reference is the first to give readers a comprehensive view of the latest macromolecular and supramolecular film-based nanotechnology. Bringing together all the important facets and state-of-the-art research, the two well-structured volumes cover film assembly and depostion, functionality and patterning, and analysis and characterization. The result is an in-depth understanding of the phenomena, ordering, scale effects, fabrication, and analysis of polymer ultrathin films. This book will be a valuable addition for Materials Scientists, Polymer Chemists, Surface Scientists, Bioengineers, Coatings Specialists, Chemical Engineers, and Scientists working in this important research field and industry.

Author : Anil N. Netravali
Publisher : John Wiley & Sons
Page : 444 pages
File Size : 27,72 MB
Release : 2016-11-29
Category : Technology & Engineering
ISBN : 1119185130

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Significant research has been done in polymeric nanocomposites and progress has been made in understanding nanofiller-polymer interface and interphase and their relation to nanocomposite properties. However, the information is scattered in many different publication media. This is the first book that consolidates the current knowledge on understanding, characterization and tailoring interfacial interactions between nanofillers and polymers by bringing together leading researchers and experts in this field to present their cutting edge research. Eleven chapters authored by senior subject specialists cover topics including: Thermodynamic mechanisms governing nanofiller dispersion, engineering of interphase with nanofillers Role of interphase in governing the mechanical, electrical, thermal and other functional properties of nanocomposites, characterization and modelling of the interphase Effects of crystallization on the interface, chemical and physical techniques for surface modification of nanocellulose reinforcements Electro-micromechanical and nanoindentation techniques for interface evaluation, molecular dynamics (MD) simulations to quantify filler-matrix adhesion and nanocomposite mechanical properties.

Author : Olga A. Shenderova
Publisher : William Andrew
Page : 582 pages
File Size : 10,4 MB
Release : 2012-09-11
Category : Science
ISBN : 1437734650

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Ultrananocrystalline Diamond: Synthesis, Properties, and Applications is a unique practical reference handbook. Written by the leading experts worldwide it introduces the science of UNCD for both the R&D community and applications developers using UNCD in a diverse range of applications from macro to nanodevices, such as energy-saving ultra-low friction and wear coatings for mechanical pump seals and tools, high-performance MEMS/NEMS-based systems (e.g. in telecommunications), the next generation of high-definition flat panel displays, in-vivo biomedical implants, and biosensors. This work brings together the basic science of nanoscale diamond structures, with detailed information on ultra-nanodiamond synthesis, properties, and applications. The book offers discussion on UNCD in its two forms, as a powder and as a chemical vapor deposited film. Also discussed are the superior mechanical, tribological, transport, electrochemical, and electron emission properties of UNCD for a wide range of applications including MEMS/ NEMS, surface acoustic wave (SAW) devices, electrochemical sensors, coatings for field emission arrays, photonic and RF switching, biosensors, and neural prostheses, etc. Ultrananocrystalline Diamond summarises the most recent developments in the nanodiamond field, and presents them in a way that will be useful to the R&D community in both academic and corporate sectors. Coverage of both nanodiamond particles and films make this a valuable resource for both the nanotechnology community and the field of thin films / vacuum deposition. Written by the world's leading experts in nanodiamond, this second edition builds on its predecessor's reputation as the most up-to-date resource in the field.