Directed Self Organization Of Polymer Grafted Nanoparticles In Polymer Thin Films

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Directed Self-organization of Polymer-grafted Nanoparticles in Polymer Thin Films

Author : Ren Zhang (Chemical engineer)
Publisher :
ISBN 13 :
Total Pages : 157 pages
Book Rating : 4.:/5 (1 download)

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Book Synopsis Directed Self-organization of Polymer-grafted Nanoparticles in Polymer Thin Films by : Ren Zhang (Chemical engineer)

Download or read book Directed Self-organization of Polymer-grafted Nanoparticles in Polymer Thin Films written by Ren Zhang (Chemical engineer) and published by . This book was released on 2016 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: The controlled organization of nanoparticle (NP) constituents into superstructures of well-defined shape, composition and connectivity represents a continuing challenge in the development of novel hybrid materials for many technological applications. Surface modification of NPs with grafted polymer ligands has emerged as a versatile means to control the interaction and organization of particle constituents in polymer-matrix composite materials. In this study, by incorporating polymer-grafted nanoparticles (PGNPs) into polymeric thin films, we aim to understand and control the spatial organization of PGNPs through the interactions between polymer brush layer and matrix chains. As model systems, we investigate thermodynamic behaviors of polystyrene-tethered gold nanoparticles (denoted as AuPS) dispersed in polymer thin film matrices with identical and different chemical compositions (PS and PMMA, respectively), and evaluate the influence of external perturbation fields on directed organization of nanofillers.With the presence of unfavorable enthalpic interactions between grafted and free polymer chains (i.e. AuPS/ PMMA blend thin films), phase-separated structures are generated upon thermal annealing, characterized with morphologies ranging from discrete droplets to spinodal structures, which is consistent with composition-dependent classic binary polymer blends phase separation. The phase separation kinetics of AuPS/ PMMA blends exhibit distinct features compared to the parent PS/ PMMA homopolymer blends. We further illustrate phase-separated AuPS-rich domains can be directed into unidirectionally aligned anisotropic structures through soft-shear dynamic zone annealing (DZA-SS) process with tunable domain aspect ratios.To exert exquisite control over the shape, size and location of phase-separated PGNP domains, topographically patterned elastomer confinement is introduced to PGNP/ polymer blend thin films during thermal annealing. When the phase-separated lengthscale coincides with confined pattern dimension, long-range ordered submicron-sized AuPS domains are generated in PMMA matrices with dense and well-dispersed nanoparticle distribution. Furthermore, preferential segregation of AuPS nanoparticles at patterned mesa regions can be induced in PS matrices where enthalpic interactions are absent. This selective segregation is achieved due to the local perturbation of grafted chains when confined in a restricted space. The efficiency of this particle segregation process within patterned mesa-trench films can be tuned by changing the relative entropic confinement effects on grafted and matrix chains. This physical pattern directed PGNP organization strategy is applicable to versatile pattern geometries and nanoparticle compositions.

Nanoimprinting-directed Assembly of Polymer-grafted Nanoparticles in Polymer Thin Films

Author : Xiaoteng Wang
Publisher :
ISBN 13 :
Total Pages : 172 pages
Book Rating : 4.:/5 (124 download)

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Book Synopsis Nanoimprinting-directed Assembly of Polymer-grafted Nanoparticles in Polymer Thin Films by : Xiaoteng Wang

Download or read book Nanoimprinting-directed Assembly of Polymer-grafted Nanoparticles in Polymer Thin Films written by Xiaoteng Wang and published by . This book was released on 2019 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Directed Self-assembly of Block Co-polymers for Nano-manufacturing

Author : Roel Gronheid
Publisher : Woodhead Publishing
ISBN 13 : 0081002610
Total Pages : 328 pages
Book Rating : 4.0/5 (81 download)

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Book Synopsis Directed Self-assembly of Block Co-polymers for Nano-manufacturing by : Roel Gronheid

Download or read book Directed Self-assembly of Block Co-polymers for Nano-manufacturing written by Roel Gronheid and published by Woodhead Publishing. This book was released on 2015-07-17 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: The directed self-assembly (DSA) method of patterning for microelectronics uses polymer phase-separation to generate features of less than 20nm, with the positions of self-assembling materials externally guided into the desired pattern. Directed self-assembly of Block Co-polymers for Nano-manufacturing reviews the design, production, applications and future developments needed to facilitate the widescale adoption of this promising technology. Beginning with a solid overview of the physics and chemistry of block copolymer (BCP) materials, Part 1 covers the synthesis of new materials and new processing methods for DSA. Part 2 then goes on to outline the key modelling and characterization principles of DSA, reviewing templates and patterning using topographical and chemically modified surfaces, line edge roughness and dimensional control, x-ray scattering for characterization, and nanoscale driven assembly. Finally, Part 3 discusses application areas and related issues for DSA in nano-manufacturing, including for basic logic circuit design, the inverse DSA problem, design decomposition and the modelling and analysis of large scale, template self-assembly manufacturing techniques. Authoritative outlining of theoretical principles and modeling techniques to give a thorough introdution to the topic Discusses a broad range of practical applications for directed self-assembly in nano-manufacturing Highlights the importance of this technology to both the present and future of nano-manufacturing by exploring its potential use in a range of fields

Polymer Thin Films

Author : Ophelia Kwan Chui Tsui
Publisher : World Scientific
ISBN 13 : 9812818820
Total Pages : 312 pages
Book Rating : 4.8/5 (128 download)

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Book Synopsis Polymer Thin Films by : Ophelia Kwan Chui Tsui

Download or read book Polymer Thin Films written by Ophelia Kwan Chui Tsui and published by World Scientific. This book was released on 2008 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ch. 1. Block copolymer thin films / J.-Y. Wang, S. Park and T. P. Russell -- ch. 2. Equilibration of block copolymer films on chemically patterned surfaces / G. S. W. Craig, H. Kang and P. F. Nealey -- ch. 3. Structure formation and evolution in confined cylinder-forming block copolymers / G. J. A. Sevink and J. G. E. M. Fraaije -- ch. 4. Block copolymer lithography for magnetic device fabrication / J. Y. Cheng and C. A. Ross -- ch. 5. Hierarchical structuring of polymer nanoparticles by self-organization / M. Shimomura ... [et al.] -- ch. 6. Wrinkling polymers for surface structure control and functionality / E. P. Chan and A. J. Crosby -- ch. 7. Crystallization in polymer thin films: morphology and growth / R. M. Van Horn and S. Z. D. Cheng -- ch. 8. Friction at soft polymer surface / M. K. Chaudhury, K. Vorvolakos and D. Malotky -- ch. 9. Relationship between molecular architecture, large-strain mechanical response and adhesive performance of model, block copolymer-based pressure sensitive adhesives / C. Creton and K. R. Shull -- ch. 10. Stability and dewetting of thin liquid films / K. Jacobs, R. Seemann and S. Herminghaus -- ch. 11. Anomalous dynamics of polymer Films / O. K. C. Tsui.

Self-Organization and Controlled Spatial Distribution of Cellulosic Nanofillers in Polymer Thin Films

Author : Danielle Grolman
Publisher :
ISBN 13 :
Total Pages : 164 pages
Book Rating : 4.:/5 (12 download)

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Book Synopsis Self-Organization and Controlled Spatial Distribution of Cellulosic Nanofillers in Polymer Thin Films by : Danielle Grolman

Download or read book Self-Organization and Controlled Spatial Distribution of Cellulosic Nanofillers in Polymer Thin Films written by Danielle Grolman and published by . This book was released on 2017 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer nanocomposites have generated widespread interest towards the development of engineered multifunctional materials and novel hybrid assemblies for high performance applications. The addition of anisotropic nanofillers in a polymer matrix can potentially modify the material's optical, thermal, electrical, or mechanical properties due to the high surface area to volume ratio, with increasing advances and focused efforts toward the development of environmentally friendly, reinforced materials from sustainable resources. In this regard, cellulose nanocrystals (CNCs) are promising nanomaterials derived from the world's most abundant natural polymer. However, one of the key challenges and current barriers towards commercialization is controlling uniform dispersion within the polymer matrix in order to achieve effective reinforcement. The objective of this research aims to gain a fundamental understanding on how to control the dispersion and spatial organization of cellulose nanocrystals in polymer thin films by tailoring the thermodynamic interactions between the host polymer matrix and rod-like nanoparticles.The first part of this dissertation focuses on developing a facile strategy to manipulate the spatial distribution of cellulose nanocrystals in polymer thin films, which are highly susceptible to particle aggregation due to strong hydrogen bonding interactions. A model symmetric diblock copolymer poly(styrene-block-methyl methacrylate) (PS-b-PMMA) was utilized as an ideal nanostructured template to selectively sequester and organize the cellulose nanocrystals via directed self-assembly wherein the CNCs were subjected to a degree of confinement within the multilayered structure. The incorporation of anisotropic nanofillers was observed to perturb the block copolymer (BCP) morphology at relatively low nanofiller concentrations. Surface chemistry modification of the nanoparticle was employed to alter interparticle and particle-polymer interactions and subsequently control nanoparticle distribution. Furthermore, significant enhancement in the mechanical performance of these polymer nanocomposite systems were attributed to the multiscale interfacial interactions between the polymer matrix and fillers. To gain insight into the stabilization and wetting behavior of polymer nanocomposite thin films, the presence of anisotropic nanofillers in a polymer matrix was investigated on non-wetting, low surface energy substrates. Control measurements on the film morphology of homopolymer systems without nanoparticles exhibited immediate film rupture and dewetting due to unfavorable interactions between the substrate and polymer thin film. The addition of cellulose nanocrystals was observed to significantly retard dewetting kinetics and resulted in dewetting suppression where thin film stabilization was achieved at a critical particle threshold. These findings exploit the tunable wettability and nanoparticle-induced stabilization of nanoscale films without any required substrate modification which could have significant ramifications towards the development of novel functional coatings.

Nanostructured Polymer Blends

Author : Juan Rodríguez-Hernández
Publisher : Elsevier Inc. Chapters
ISBN 13 : 012809088X
Total Pages : 108 pages
Book Rating : 4.1/5 (28 download)

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Book Synopsis Nanostructured Polymer Blends by : Juan Rodríguez-Hernández

Download or read book Nanostructured Polymer Blends written by Juan Rodríguez-Hernández and published by Elsevier Inc. Chapters. This book was released on 2013-11-28 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: The design of polymer blends constitutes an interesting alternative to obtaining micro- and nanostructured surfaces. The cost is reasonable and it is free from time-consuming procedures. Blending of polymers can yield materials with unprecedented properties that cannot be provided otherwise by using a single polymer. The free surface topography of polymer blend films, often related to phase domain structure, is critical to the applications. Two main aspects need to be considered in the preparation of multistructured blends: the interfaces involved and the morphology to be obtained. The control of these two aspects depends further on materials-related parameters involving the composition of the blend, the interfacial tension or viscosity ratio, and the processing conditions related to the temperature, time, or intensity of mixing, among others. Both domain structure and topography of the blend films have garnered increasing interest over the past decade. This chapter describes the nanomicrostructures formed at the polymer surface from polymer blends. Despite the crucial role that surfaces play in the final application of the material, up to now most of the studies concerning polymer blends have been related to the control of the mechanical properties (toughness, stiffness, thermal expansion, etc.), their barrier properties, or the electrical conductivity. This chapter focuses on the analysis of the structured polymer surfaces and thin films, giving an overview of the role of these structures on the final application. The principles of phase separation and the resulting structures formed are briefly discussed, followed by a wide overview of the possibilities of producing stimuli-responsive interfaces by introducing, among other things, pH- or temperature-responsive polymers within the blend. Finally, we look at how using particular preparation conditions and/or self-assembly of block copolymers, the formation of films and surfaces with hierarchical order length-scales can be induced. We also examine the main areas in which multiscale-ordered interfaces obtained from polymer blends have been applied.

Brush-Coated Nanoparticle Polymer Thin Films

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (925 download)

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Book Synopsis Brush-Coated Nanoparticle Polymer Thin Films by :

Download or read book Brush-Coated Nanoparticle Polymer Thin Films written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Executive Summary Our work was devoted to understanding the structure and properties of a class of thin film polymer nanocomposites (PNCs). PNCs are composed of polymer hosts into which nanoparticles (metallic nanoparticles, quantum dots, nanorods, C60, nanotubes) are incorporated. PNCs exhibit a diverse range of functional properties (optical, electronic, mechanical, biomedical, structural), determined in part by the chemical composition of the polymer host and the type of nanoparticle. The properties PNCs rely not only on specific functional, size-dependent, behavior of the nanoparticles, but also on the dispersion, and organizational order in some cases, inter-nanoparticle separation distances, and on relative interactions between the nanoparticles and the host. Therefore the scientific challenges associated with understanding the interrelations between the structure and function/properties of PNCs are far more complex than may be understood based only on the knowledge of the compositions of the constituents. The challenges of understanding the structure-function behavior of PNCs are further compounded by the fact that control of the dispersion of the nanoparticles within the polymer hosts is difficult; one must learn how to disperse inorganic particles within an organic host. The goal of this proposal was to develop an understanding of the connection between the structure and the thermal (glass transition), mechanical and optical properties of a specific class of PNCs. Specifically PNCs composed of polymer chain grafted gold nanoparticles within polymer hosts. A major objective was to understand how to develop basic principles that enable the fabrication of functional materials possessing optimized morphologies and combinations of materials properties. Accomplishments: We developed: (1) fundamental principles that enabled the creation of thin film PNCs possessing more complex morphologies of homopolymers and block copolymer micellar systems [1-6]; (2) a new understanding of physical phenomena associated with the structure of PNC systems and the glass transition and dynamics [7-11], including surface dynamics [12, 13]; designed PNCs to understand the connection between structure and specific optical responses of the material [14, 15]; electrorheological phenomena [16-18]; coarsening/aggregation phenomena [19, 20]; directed assembly [21] and elastic mechanical properties of thin supported films [22]. We established procedures to design and control the spatial distribution of gold nanoparticles (Au-NP), onto which polystyrene (PS) chains were end-grafted, within thin film PS hosts.[1-3] We explained how enthalpic and entropic interactions between the grafted layers and the polymer host chains, the nanoparticle (NP) sizes and shapes determine the spatial distribution of NPs within the host (i.e.: the morphology). In brief, the chemistries of the grafted chains and the polymer hosts, the degrees of polymerization of grafted and host chains (N and P, respectively), and the surface grafting densities [Sigma] influence the thermodynamic interactions. Thin films are unique: the external interfaces (substrate and free surface) profoundly influence the spatial distribution of NPs within the PNC. For example, thin films are thermodynamically less stable than their bulk analogs due to the preferential attraction between the brush-coated nanoparticles and the external interfaces (i.e.: the free surface/polymer interface and the polymer/substrate interface). We investigated the organization of the brush-coated nanoparticles within a host composed on block copolymer micelles in a homopolymer [4, 5]. Block copolymers, composed of a polymer of type A that is bonded covalently to another polymer of type B (A-b-B) are known to form micelles within homopolymers A or B.A micelle is composed of an inner core of the A component of the copolymer and an outer corona of the B-component, that resides within homopolymer B, which serves as the host. If t ...

Phase Separation of Polymer-grafted Nanoparticle Blend Thin Films

Author : Yue Zhang
Publisher :
ISBN 13 :
Total Pages : 45 pages
Book Rating : 4.:/5 (14 download)

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Book Synopsis Phase Separation of Polymer-grafted Nanoparticle Blend Thin Films by : Yue Zhang

Download or read book Phase Separation of Polymer-grafted Nanoparticle Blend Thin Films written by Yue Zhang and published by . This book was released on 2017 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays, the addition of nanoparticles (NPs) in polymer has attracted intensive attention because nanoparticles can bring some excellent properties to polymer materials. To get better control of the dispersion of NPs, polymer-grafted nanoparticle (PGNP) has been used in this work because the polymer ligands on the surface of NPs can give phase separation in the system. The phase separation behavior of bianary PGNP blend thin films has been investigated in this work. The blend thin film is composed of PS-g-SiO2 and PMMA-g-SiO2 nanoparticles. The phase-separated domain growth was slower than PGNP blends with shorter grafted chain lengths. With the application of capillary force lithography (CFL), more PMMA-g-SiO2 nanoparticles were segregated in imprinted trenches with longer thermal annealing time. In contrast, faster soft-shear cold-zone-annealing (CZA-SS) speed induced selective segregation of PMMA-g-SiO2 particles. The process under CFL is a wetting-driven process and that under CZA-SS is a shear-driven process.

Directed Nano-Patterning of Polymer Nanocomposite Thin Films

Author : Xiaoteng Wang
Publisher :
ISBN 13 :
Total Pages : 75 pages
Book Rating : 4.:/5 (96 download)

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Book Synopsis Directed Nano-Patterning of Polymer Nanocomposite Thin Films by : Xiaoteng Wang

Download or read book Directed Nano-Patterning of Polymer Nanocomposite Thin Films written by Xiaoteng Wang and published by . This book was released on 2016 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer-nanoparticle (NP) composites have been studied extensively as a core material that exhibits advantageous optical, electrical and mechanical properties in nanotechnology. It has been well-established that a specific distribution state of nanoparticles in a polymer matrix is the key issue to optimize a desired polymer nanocomposite (PNC) property. However effective way of controlling the spatial distribution of nanoparticles is still a recurring challenge. Here we demonstrated facile processing approach to fabricate nanocomposite thin films with controlled nanoparticle dispersion state by exploiting the entropic interactions, thereby controlling the macroscopic performance of the material. The interactions of nanoparticles with polymers are mediated by the ligands attached to the nanoparticles. Location and dispersion of polystyrene grafted titanium dioxide (PS-g-TiO2) and hydroxyl-functionalized polyhedral oligomeric silsesquioxanes (DPOSS) molecular nanoparticles in homopolymer matrices under various annealing conditions were investigated. PS-g-TiO2 NP filled low molecular weight polystyrene thin films were thermally annealed under nanoscale pattern confinement, which was fabricated by imprinting digital recording media discs (DVD) pattern onto polydimethylsiloxane (PDMS). The NP dispersion changed from randomly distributed to aggregating at the elevated regions of the imprinted films due to the entropic interaction caused by the size difference between the particles and the matrix chains. DPOSS-PS is a type of giant shape amphiphiles which are built up by covalent bonding of molecular nanoparticles. When added to low molecular weight homopolymer matrices, DPOSS-PS nanoparticles exhibited better dispersion in PMMA than in PS matrix. Additionally, to understand the morphology transition and phase separation kinetics, various loading fraction of DPOSS-PS were incorporated into PMMA matrix. Phase separation at multiple length scales was observed when the composition of DPOSS-PS is in the range of 5% and 70%.

Polymer-Mediated Assembly of Nanoparticles Into Anisotropic Architectures

Author : Tsung-Yeh Tang
Publisher :
ISBN 13 :
Total Pages : 156 pages
Book Rating : 4.:/5 (111 download)

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Book Synopsis Polymer-Mediated Assembly of Nanoparticles Into Anisotropic Architectures by : Tsung-Yeh Tang

Download or read book Polymer-Mediated Assembly of Nanoparticles Into Anisotropic Architectures written by Tsung-Yeh Tang and published by . This book was released on 2019 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Directed Self-assembly in Block Polymer Thin Films

Author : Cameron K. Shelton
Publisher :
ISBN 13 : 9780355465679
Total Pages : 273 pages
Book Rating : 4.4/5 (656 download)

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Book Synopsis Directed Self-assembly in Block Polymer Thin Films by : Cameron K. Shelton

Download or read book Directed Self-assembly in Block Polymer Thin Films written by Cameron K. Shelton and published by . This book was released on 2017 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block polymers (BPs) have attracted significant attention for emerging nanotechnologies such as nanolithographic masks, nanotemplates, nanoporous membranes, organic photovolatics, and lithium ion battery membranes due to their ability to self-assembly into periodic assemblies of nanoscale features. Many of these applications require thin film geometries, which have additional confinement interactions in comparison to bulk self-assembly that must be understood to control nanostructure orientation, ordering, and alignment precisely. Two approaches to study the nuanced effects of these additional interactions are in situ characterization and neutron scattering, used concurrently or independently. With these techniques, more predictive and optimized methods to direct self-assembly can be established to unlock the full potential of BP thin films in commercial and research applications. In this dissertation work, four aspects of BP thin film self-assembly were explored with these powerful characterization tools. First, chlorosilane-modified substrate surfaces were employed to investigate the effect of the substrate-polymer interaction on nanostructure orientation and ordering. Predictive formalisms were developed that defined substrate wetting behavior, nanostructure ordering, and through-film orientation control as a function of total and decoupled (dispersive and polar) substrate-polymer interfacial energy components. Second, solvent vapor annealing was studied with in situ small-angle neutron scattering (SANS), neutron reflectometry (NR), and selective deuteration to determine how factors such as solvent-polymer interactions and solvent concentration affected BP thin film self-assembly. Next, in situ SANS during solvent vapor annealing with soft shear (SVA-SS) was used to track shear-induced nanostructure disordering and ordering. By understanding the kinetic pathways during SVA-SS, more robust and high-throughput methods to define the alignment direction(s) were developed. Lastly, lithium salt-doped poly(styrene-b-oligo[oxyethylene] methacrylate) films were investigated with NR to achieve the first high-resolution, non-destructive, and quantitative analysis regarding how lithium salts distribute within the conducting domain of BP electrolyte thin films. Overall, the work in this dissertation contributes predictive and translatable approaches to direct self-assembly and the design of powerful characterization strategies to extract key information from BP thin film systems to improve their rational design and application.

Control of C60-POSS Nanoparticle Locaiton in Directed Self-assembly of Block Copolymer Thin Films

Author : Jiajie Qian
Publisher :
ISBN 13 :
Total Pages : 53 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Control of C60-POSS Nanoparticle Locaiton in Directed Self-assembly of Block Copolymer Thin Films by : Jiajie Qian

Download or read book Control of C60-POSS Nanoparticle Locaiton in Directed Self-assembly of Block Copolymer Thin Films written by Jiajie Qian and published by . This book was released on 2014 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the advantage in self-assembly property of block copolymer (BCP), the nanoscale periodic patterns produced by the block copolymer have recently been identified as the next-generation precursor technique in many fields like nanolithographic templates, magnetic data storage, nanoporous membranes. The range of BCP periodicity is usually between 5nm and 100nm. By changing the molecular weight (N), volume fraction (f) of the components and segmental interaction, the anticipated results vary. These variations include BCP with lamellar, cylindrical, gyroid and spherical structures. Cylinder and lamella BCP are the invested especially popular, as their strong preferential interaction on the substrate results in the parallel or vertical orientation of micro domain. On the other hand, the material properties such as conductivity, hydrophilicity, mechanical and optical properties will be significantly affected depending on the way how nanoparticles (NPs) disperse within the polymer matrix. Therefore the ability to control the NPs arrangement is required. Although, a variety of methods have been explored to guide the NPs into the expected location, the ability to control positioning is still very limited, especially when the novel NPs are applied. The kinetics and intermolecular attraction are the generally accepted methods used to estimate the NPs location. In this study, location and dispersion of dumbbell-shaped fullerene (C60) bonding polyhedral oligomeric silsesquioxane (POSS) NPs were investigated on a variety of polystyrene (PS) and polymethylmethacrylate (PMMA) derivative polymer conditions. In the cases of homopolymers and polymer blends samples, the priority of C60-POSS NPs to PMMA phase was achieved due to the intermolecular forces. For the Z-direction distribution, enrichment areas of C60-POSS NPs were detected both on the top layer and bottom layer after the thin film samples were annealed due to the lower surface energy of C60-POSS NPs. Additionally, the exotic C60-POSS NPs would affect the PS-PMMA block copolymer self-assembly results involving both surface morphology and inner structure. More horizontal cylinders would form as the proportion of C60-POSS NPs was increased. In this study, Cold Zone Annealing-sharp was also used as a novel thermal annealing approach to explore the potential influences on the alignment of BCP/NPs nanocomposite.

Assembly of Polymer-Grafted Nanoparticles in Polymer Matrices

Author : Clement Koh
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (125 download)

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Book Synopsis Assembly of Polymer-Grafted Nanoparticles in Polymer Matrices by : Clement Koh

Download or read book Assembly of Polymer-Grafted Nanoparticles in Polymer Matrices written by Clement Koh and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Entropic effects, i.e. the translational entropy of the NPs and the matrix, the entropy of mixing of the grafts and the matrix, and the conformational entropy of the chains appear to thus play a second order effect even in the context of these model systems. Each of these insights provides details around controlling the organization and assembly of NPs in polymers for the purpose of improving their mechanical properties, all while changing the way in which the material is designed.

Anisotropic Self-Assembly of Spherical Polymer-Grafted Nanoparticles

Author :
Publisher :
ISBN 13 :
Total Pages : 7 pages
Book Rating : 4.:/5 (574 download)

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Book Synopsis Anisotropic Self-Assembly of Spherical Polymer-Grafted Nanoparticles by :

Download or read book Anisotropic Self-Assembly of Spherical Polymer-Grafted Nanoparticles written by and published by . This book was released on 2009 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Polymer-grafted Au Nanorods in Polymer Thin Films

Author : Michael-Jon Ainsley Hore
Publisher :
ISBN 13 :
Total Pages : 183 pages
Book Rating : 4.:/5 (893 download)

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Book Synopsis Polymer-grafted Au Nanorods in Polymer Thin Films by : Michael-Jon Ainsley Hore

Download or read book Polymer-grafted Au Nanorods in Polymer Thin Films written by Michael-Jon Ainsley Hore and published by . This book was released on 2012 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt:

An Investigation Into the Structural Design of Polymer Thin Films

Author : Rachel Irene Ramirez
Publisher :
ISBN 13 :
Total Pages : 203 pages
Book Rating : 4.:/5 (114 download)

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Book Synopsis An Investigation Into the Structural Design of Polymer Thin Films by : Rachel Irene Ramirez

Download or read book An Investigation Into the Structural Design of Polymer Thin Films written by Rachel Irene Ramirez and published by . This book was released on 2018 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding how the structural design of polymer thin films impacts their response to stimuli, such as pH, is crucial for developing systems with targeted attributes to further expand the scope of their applications. These polymer systems can be modified based on the choice of monomers, composition, and structural design, which provides a tunable source for both functionality and tailorability. This tailorability in design gives rise to a wide array of molecular properties that have a significant impact on the macroscopic properties of thin films. This dissertation work aims to provide insight into how the structural design can impact properties on two categories of polymer thin films: copolymer-grafted nanocomposites and polymer brushes. Copolymer nanocomposites were investigated on how the miscibility of the copolymer-grafted nanoparticles can be tuned by using the enthalpic interactions between the graft and the polymer matrix. Changing the overall composition of the copolymer allowed us to drive dispersion of the resulting nanocomposites in the matrix. The copolymer-grafted nanoparticles were synthesized using surface-initiated activators regenerated via electron transfer atom transfer radical polymerization in which poly(methyl methacrylate-r-cyclohexyl methacrylate) was grown from the silica nanoparticle surface and dispersed in a chemically dissimilar polystyrene matrix. An investigation into how the thermomechanical properties of the resulting copolymer-grafted nanocomposites was conducted using fused deposition modeling. The second category of polymer thin films examined was polyampholyte brushes in which the impact of modifying the composition on swelling behavior was investigated. Polyampholytes are comprised of charge-positive and charge-negative repeat units, which directly contributes to trade-offs between charge which is externally regulated by solution pH and added salt, and structure. A series of swelling studies were performed to examine how copolymer composition affects structural response of random polyampholyte brushes as pH is changed and betaine, a zwitterion, is added. The work in this dissertation involves the investigation of several types of polymer thin films, the common theme is clarifying how the structural design and composition affects the properties of polymer brushes, both as copolymer-grafted nanocomposites and on planar surfaces. In total, this research provides insight into how polymer design, polymer structure, and behavior responses are associated.

Self-Healing Polymers

Author : Wolfgang H. Binder
Publisher : John Wiley & Sons
ISBN 13 : 3527670203
Total Pages : 638 pages
Book Rating : 4.5/5 (276 download)

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Book Synopsis Self-Healing Polymers by : Wolfgang H. Binder

Download or read book Self-Healing Polymers written by Wolfgang H. Binder and published by John Wiley & Sons. This book was released on 2013-03-29 with total page 638 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-healing is a well-known phenomenon in nature: a broken bone merges after some time and if skin is damaged, the wound will stop bleeding and heals again. This concept can be mimicked in order to create polymeric materials with the ability to regenerate after they have suffered degradation or wear. Already realized applications are used in aerospace engineering, and current research in this fascinating field shows how different self-healing mechanisms proven successful by nature can be adapted to produce even more versatile materials. The book combines the knowledge of an international panel of experts in the field and provides the reader with chemical and physical concepts for self-healing polymers, including aspects of biomimetic processes of healing in nature. It shows how to design self-healing polymers and explains the dynamics in these systems. Different self-healing concepts such as encapsulated systems and supramolecular systems are detailed. Chapters on analysis and friction detection in self-healing polymers and on applications round off the book.