Download or read book Modeling and Theoretical Design Methods for Directed Self assembly of Thin Film Block Copolymer Systems written by Adam Floyd Hannon and published by . This book was released on 2014 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block copolymers (BCPs) have become a highly studied material for lithographic applications due to their ability to self-assemble into complex periodic patterns with feature resolutions ranging from a few to 100s nm. BCPs form a wide variety of patterns due the combination of their enthalpic interactions promoting immiscibility between the blocks and the bonding constraint through their chain topology. The morphologies formed can be tailored through a directed self-assembly (DSA) process using chemical or topographical templates to achieve a desired thin film pattern. This method combines the traditional top-down lithographic methods with the bottom-up self-assembly process to obtain greater control over long range order, the local morphology, and overall throughput of the patterns produced. This work looks at key modeling challenges in optimizing BCP DSA to achieve precision morphology control, reproducibility, and defect control. Modeling techniques based on field theoretic simulations are used to both characterize and predict the morphological behavior of a variety of BCPs under a variety of processing conditions including solvent annealing and DSA under topographical boundary conditions. These methods aid experimental studies by saving time in performing experiments over wide parameter spaces as well as elucidating information that may not be available by current experimental techniques. Both forward simulation approaches are studied where parameters are varied over a wide range with phase diagrams of potential morphologies characterized and inverse design approaches where given target patterns are taken as simulation input and required conditions to produce those patterns are outputted from the simulation for experimental testing. The studies ultimately help identify the key control parameters in BCP DSA and enable a vast array of possible utility in the field.
Download or read book Computation by Block Copolymer Self assembly written by Hyung Wan Do and published by . This book was released on 2018 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unconventional computation is a paradigm of computation that uses novel information tokens from natural systems to perform information processing. Using the complexity of physical systems, unconventional computing systems can efficiently solve problems that are difficult to solve classically. In this thesis, we use block copolymer self-assembly, a well-studied phenomenon in polymer science, to develop a new approach to computing by applying directed self-assembly to implement Ising-model-based computing systems in materials. In the first part of the thesis, we investigate directed self-assembly of block copolymer thin films within templates of different polygonal shapes. We define a two-state system based on the two degenerate alignment orientations of the ladder-shaped block copolymer structures formed inside square confinements, and study properties of the two-state system. In the second part of the thesis, we demonstrate an Ising lattice setup for directed self-assembly of block copolymers defined on two-dimensional arrays of posts. We develop an Ising-model-based simulation method that can perform block copolymer pattern prediction and template design. Finally, we design simple Boolean logic gates as a proof-of-concept demonstration of computation.
Download or read book Block Copolymer Self assembly a Computational Approach Towards Novel Morphologies written by Karim Raafat Gadelrab and published by . This book was released on 2019 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spontaneous self-assembly of materials is a phenomenon exhibited by different molecular systems. Among many, Block copolymers (BCPs) proved to be particularly interesting due to their ability to microphase separate into periodic domains. Nonetheless, the rising need for arbitrary, complex, 3D nanoscale morphology shows that what is commonly achievable is quite limited. Expanding the range of BCPs morphologies could be attained through the implementation of a host of strategies that could be used concurrently. Using directed self-assembly (DSA), a sphere forming BCP was assembled in a randomly displaced post template to study system resilience towards defect creation. Template shear-like distortion seemed to govern local defect generation. Defect clusters with symmetries compatible with that of the BCP showed enhanced stability. Using 44 and 32434 Archimedean tiling templates that are incompatible with BCP six-fold symmetry created low symmetry patterns with an emergent behavior dependent on pattern size and shape. A variation of DSA is studied using modulated substrates. Layer-by-layer deposition of cylinder forming BCPs was investigated. Self-consistent field theory (SCFT) and strong segregation theory SST were employed to provide the understanding and the conditions under which particular orientations of consecutive layers were produced. Furthermore, deep functionalized trenches were employed to create vertically standing high-[chi] BCP structures. Changing annealing conditions for a self-assembled lamellar structure evolved the assembled pattern to a tubular morphology that is non-native to diblock copolymers. A rather fundamental but challenging strategy to go beyond the standard motifs common to BCPs is to synthesize multiblock molecules with an expanded design space. Triblock copolymers produced bilayer perforated lamellar morphology. SCFT analysis showed a large window of stability of such structures in thin films. In addition, a model for bottlebrush BCPs (BBCPs) was constructed to investigate the characteristics of BBCPs self-assembly. Pre-stacked diblock sidechains showed improved microphase separation while providing domain spacing relevant to lithography applications. A rich phase diagram was constructed at different block concentrations. The ability to explore new strategies to discover potential equilibrium morphologies in BCPs is supported by strong numerical modeling and simulations efforts. Accelerating SCFT performance would greatly benefit BCP phase discovery. Preliminary work discussed the first attempt to Neural Network (NN) assisted SCFT. The use of NN was able to cut on the required calculations steps to reach equilibrium morphology, demonstrating accelerated calculation, and escaping trapped states, with no effect on final structure.
Download or read book Predictive Modeling and Uncertainty Quantification for Diblock Copolymer Self assembly written by Lianghao Cao and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diblock copolymers (Di-BCP) are polymers consistent of two blocks of distinct monomers. Upon thermal or solvent annealing, the two blocks in a Di-BCP melt spontaneously segregate as a result of their incompatibility. Periodically-ordered nano-scale structures emerge as the melt achieves an equilibrium. This phenomenon is known as the self-assembly of Di-BCPs. The self-assembly can be further influenced by external guidance, such as chemically modified substrates, enabling the design of complex nano-structures. This process is referred to as the directed self-assembly (DSA) of Di-BCPs. The DSA of BCPs has attracted massive attention for its application in patterning for lithography to be used for fabricating nano-scale devices. Recently, there has been a rising interest in making consequential decisions based on computer simulations of Di-BCP self-assembly; most noticeably being the use of model-based simulations to propose DSA procedures for meeting the manufacturing constraints of nanofabrication. With the growing impact of computer simulations in the applications of the self-assembly, it is more imperative than ever to understand as well as systematically control and enhance the quality, validity, and reliability of these simulations. Aiming at these goals, this study focuses on predictive modeling with quantified uncertainties for Di-BCP self-assembly. First, the physical and mathematical origins of models for Di-BCP self-assembly are presented to set the ground for understanding the predictability of continuum models for the self-assembly, such as those based on self-consistent field theory and density functional theory. Then fast algorithms are designed based on approximations of the Hessian operators for solving these models via free energy minimization. These algorithms help accelerate many-query applications, such as design and inverse problems, associated with model-based simulations of Di-BCP self-assembly. A Bayesian framework for predictive modeling of Di-BCP thin film self-assembly via the Occam Plausibility Algorithm is presented. This procedure involves model calibration, selection, and validation centered around Bayes' rule and image data produced by microscopy or X-ray scattering characterizations. The aleatoric uncertainties of Di-BCP self-assembly represented by metastability and defectivity require introducing randomness into model predictions. These uncertainties, however, lead to integrated likelihoods that are generally intractable to evaluate. To tackle this challenge that hampers the execution of the predictive modeling procedure, likelihood-free inference approaches via pseudo-marginal methods and measure transport are considered in this study. To improve the efficiency of these inference methodologies, they are used in adjunct with carefully designed summary statistics that extract features of characterization images. Several Fourier- and energy-based summary statistics are proposed for top-down microscopy characterizations of Di-BCP thin films. Expected information gains are used to quantify the utilities of summary statistics choices, and we show that they can be computed via measure transport with no significant additional computational cost
Download or read book Self Assembling Systems written by Li-Tang Yan and published by John Wiley & Sons. This book was released on 2016-10-06 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides comprehensive knowledge on concepts, theoretical methods and state-of-the-art computational techniques for the simulation of self-assembling systems Looks at the field of self-assembly from a theoretical perspective Highlights the importance of theoretical studies and tailored computer simulations to support the design of new self-assembling materials with useful properties Divided into three parts covering the basic principles of self-assembly, methodology, and emerging topics
Download or read book Theory of Block Polymer Self Assembly written by Benjamin R. Magruder and published by American Chemical Society. This book was released on 2024-03-13 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: This primer introduces the theory of self-assembly of block polymers, most notably self-consistent field theory (SCFT). Block polymer self-assembly is a fascinating and highly interdisciplinary topic. This primer can be read at several levels, depending on what readers want to get out of it. Readers who want an overview of self-assembly in block polymer and what SCFT says about the process can read Chapters 1-3 and skip to Chapter 7 to see the open questions. If the reader is further interested in the output of SCFT calculations but not how those outputs are generated, they should read Chapter 6 as well. But if the reader wants to learn how to do the SCFT calculations themselves, Chapters 4 and 5 offer an accessible introduction to the theory and numerical methods, providing an excellent entry point into the literature. This primer includes data that the authors have computed using SCFT. All calculations use the open-source software package Polymer Self-Consistent Field (PSCF), developed by David Morse at the University of Minnesota. Take breaks from reading to watch ten “Insider Q&A” videos included throughout, which offer additional insight from experts in the field, such as An-Chang Shi, Chinedum O. Osuji, Frank S. Bates, Christopher M. Bates, Glenn H. Fredrickson, and Lisa Hall. Furthermore, this primer includes multiple features to aid and enhance readers’ learning. “That’s a Wrap” summarizes key concepts at the end of each chapter, while “Read These Next” suggests references that may interest further reading. A pop-up glossary ensures readers have definitions as needed throughout the primer.
Download or read book Numerical Simulations of Directed Self assembly Methods in Di block Copolymer Films for Efficient Manufacturing of Nanoscale Patterns with Long range Order written by Joseph Dee Hill and published by . This book was released on 2020 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Directed self-assembly (DSA) of block copolymers (BCPs) has been shown as a viable method to achieve bulk fabrication of surface patterns with feature sizes smaller than those available through traditional photolithography. Under appropriate thermodynamic conditions, BCPs will self-assemble into ordered micro-domain morphologies, a desirable feature for many applications. One of the primary interests in this field of research is the application of thin-film BCPs to existing photolithography techniques. This "bottom-up" approach utilizes the self-assembled BCP nanostructures as a sacrificial templating layer in the lithographic process. While self-assembly occurs spontaneously, extending orientational uniformity over centimeter-length scales remains a critical challenge. A number of DSA techniques have been developed to enhance the long range order in an evolving BCP system during micro-phase separation. Of primary interest to this dissertation is the synergistic behavior between chemoepitaxial templating and cold-zone annealing. The first method involves pre-treating a substrate with chemical boundaries that will attract or repel one of the monomer blocks before application of the thin-film via spin-coating. The second method applies a mobile, thermal gradient to induce micro-phase separation in a narrow region within the homogeneous thin-film . Parametric studies have been performed to characterize the extent of long range order and defect densities obtained by applying various thermal zone velocities and template patterns. These simulations are performed by utilizing a Time-Dependent Ginzburg-Landau (TDGL) model and an optimized phase field (OPF) model. Parallel processing is implemented to allow large-scale simulations to be performed within a reasonable time period.
Download or read book Modeling Self assembly and Structure property Relationships in Block Copolymers written by Manas Ravindra Shah and published by . This book was released on 2009 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block copolymers have been subject of tremendous research interest owing to their capability of undergoing self-assembly which allows them to tailor their electrical, optical, and mechanical properties. Statistical mechanics of flexible block copolymers is well understood. However, there are many unresolved issues with confinement of block copolymers as well as structure formation in block copolymers having non-flexible polymer blocks. We develop mean field theory models to address the issues arising in thermodynamics of such complex block copolymers. Also, we develop theoretical formalisms to understand the link between morphology and macroscopic properties in these block copolymers. We study the stability and ordering in thin films of flexible diblock copolymer in the presence of compressible solvent using a combined polymer mean field theory and lattice gas model for binary fluid mixtures. We utilize mean field theory model to understand the self-assembly behavior in side-chain liquid crystalline block copolymers which involve interplay between microphase separation and liquid crystalline ordering of side chain mesogenic units. We extend the field theoretic models for block copolymer to account for self-assembly in semicrystalline block copolymers. The semicrystalline chain is modeled as a semiflexible chain having non-bonded attractions between parallel bonds. We characterize the structure formation in such block copolymers as a function of the rigidity of the semicrystalline chain. Then we extend the formalism to study semicrystalline triblock and pentablock copolymers and evaluate bridging fractions in different sequences of semicrystalline multiblock copolymers. Rod-coil block copolymers have a flexible polymer covalently linked to rigid polymer. Such polymers have potential applications as organic LEDs and photovoltaic devices. We study the self-assembly of such block copolymer under confinement. To make these block copolymers viable as photovoltaic devices, we performed the photovoltaic modeling of devices based on self-assembly of block copolymers. We characterize the interplay between self-assembly and anisotropy of charge transport (arising due to rigid polymer chains) in determining the eventual photovoltaic properties.
Download or read book Coarse Grained Modeling of Block Copolymer Lithography The Effects of Pattern Design on the Thermodynamics and Kinetics of the Directed Self Assembly of Block Copolymers written by Grant Parker Garner and published by . This book was released on 2017 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Prior to the work presented in Chapter 2, the TICG model has been used in conjunction with a chemical pattern that is approximated as a hard-impenetrable surface. As many experimental systems use polymer brushes to help guide the polymer melt deposited on the substrate, this work analyzes the consequences of such an assumption by comparing a model where the polymer brush is explicitly implemented to the hard-wall substrate used in the past. Then, a methodology which utilizes a evolutionary optimization method is used to map the parameters of the more detailed model to the hard-surface model. This provides a qualitative understanding of how to interpret the model parameters used in previous works in the context of real experimental pattern designs.
Download or read book Directed Self assembly of Block Copolymer Films on Chemically Nanopatterned Surfaces written by Adam M. Welander and published by . This book was released on 2009 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Directed Assembly of Block Copolymer Films Via Surface Energy Tunable Elastomers written by Arzu Hayirlioglu and published by . This book was released on 2014 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ordering of block copolymer (BCP) thin films has been great interest for potential applications due to nanometer scale size self-assembly pattern formation. Numerous methods (chemical, physical, etc.) have been developed to create desired alignment and ordering properties in such block copolymer systems. However, the drawback of most current technologies such as brittleness and lack conformability to different surfaces makes them difficult to implement new emerging high-tech flexible technologies. On the other hand, there is a lack of knowledge in block copolymer wettability characteristics and morphological behavior on soft substrates which makes them attractive to explore for further investigations. A notable challenge in this regard is that successful deployment of BCPs for applications requires an understanding of BCP ordering properties on flexible substrate as a function of their surface chemistry, topography including patterning, roughness, stiffness, modulus and thermal conductivity, etc. Therefore, the general purpose of this research is to investigate the thermodynamics and kinetics of directed assembly of cylinder and lamellar forming polystyrene-block-polymethlymethacrylate (PS-b-PMMA) diblock copolymer films on elastomeric polydimethylsiloxane (PDMS) substrates with controlled surface energy and substrate topography. In first part, wettability characteristics of cylinder and lamellae forming PS-b-PMMA thin films versus surface energy of elastomeric PDMS substrates were increasing surface energy of PDMS by tuning with Ultraviolet Ozone (UVO) exposure and elasticity by varying the crosslinking concentration. In this extended wetting regime gradual perpendicular to parallel orientation change was shown for lamellar BCP films unlike cylindrical films where the transition was very sharp, reflecting lamellar BCP intrinsic stability over a wider range of substrate surface energy, consistent with theoretical estimates. In second part of the study, we extended the part on wettability characteristics of polystyrene (PS) homopolymer and PS-b-PMMA block copolymer thin films on flat, periodic and non-periodic nanopatterned elastomeric PDMS substrates. We discovered creating non-periodically nanopatterned surface properties induced retardation of BCP dewetting and mostly eliminate on periodically nanopatterned surface properties without any surface chemistry modification. Time kinetic study results also showed the patterning has a slowing down effect on dewetting mechanism for both homopolymer and block copolymer systems and dewetted droplet shape. In final part of this study, we focused on block copolymer morphology on periodically and non-periodically (rough) patterned elastomeric PDMS substrates with and without tuning the substrate surface energy via UVO exposure. The regular uniform film properties were achieved with parallel or perpendicular microdomain orientation to the substrate at even imcommensurate thicknesses which normally shows island and holes on flat surfaces. In addition to the bottom pattern confinement effect on BCP ordering, uniform size patterned elastomeric top capping layer was also used. Mixed or long range ordered structures were obtained with different annealing conditions.
Download or read book Directed Self assembly of Diblock Copolymer Thin Films on Chemically Nanopatterned Substrates written by Erik WiIliam Edwards and published by . This book was released on 2005 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Directed Self assembly of Block Copolymers for High Breakdown Strength Polymer Film Capacitors written by and published by . This book was released on 2016 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Emerging needs for fast charge/discharge yet high-power, lightweight, and flexible electronics requires the use of polymer-film-based solid-state capacitors with high energy densities. Fast charge/discharge rates of film capacitors on the order of microseconds are not achievable with slower charging conventional batteries, supercapacitors and related hybrid technologies. However, the current energy densities of polymer film capacitors fall short of rising demand, and could be significantly enhanced by increasing the breakdown strength (EBD) and dielectric permittivity ([epsilon]r) of the polymer films. Co-extruded two-homopolymer component multilayered films have demonstrated much promise in this regard showing higher EBD over that of component polymers. Multilayered films can also help incorporate functional features besides energy storage, such as enhanced optical, mechanical, thermal and barrier properties. In this work, we report accomplishing multilayer, multicomponent block copolymer dielectric films (BCDF) with soft-shear driven highly oriented self-assembled lamellar diblock copolymers (BCP) as a novel application of this important class of self-assembling materials. Results of a model PS-b-PMMA system show ~50% enhancement in EBD of self-assembled multilayer lamellar BCP films compared to unordered as-cast films, indicating that the breakdown is highly sensitive to the nanostructure of the BCP. The enhancement in EBD is attributed to the "barrier effect", where the multiple interfaces between the lamellae block components act as barriers to the dielectric breakdown through the film. The increase in EBD corresponds to more than doubling the energy storage capacity using a straightforward directed self-assembly strategy. Lastly, this approach opens a new nanomaterial paradigm for designing high energy density dielectric materials.
Download or read book Directed Self Assembly of Block Copolymers Based on the Heterogeneous Nucleation Process written by Tao Yang and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: By introducing the heterogeneous nucleation concept to directed self-assembly of block copolymers, the ordering of dynamical process and defect pattern design in thin films of binary blend, AB diblock/C homopolymer (AB/C), are investigated by the time-dependent Ginzburg-Landau theory and simulated by the cell dynamics simulations. The detailed annealing process of a few isolated defects occurring in AB/C blend under triangular and hexagonal confinements is presented, and it indicates that angle-matched confinement of triangular and hexagonal potential well is favorable conditions for generating defect-free ordered structures. Meanwhile, we gave a model which composed of many double-spot potentials with controllable position and orientation to investigate the relationship between defect spacing and mismatched angle, and we found the relationship is similar to hard crystals. Additionally, as an example, the design of defect pattern of ,ÄúNXU,Äù for abbreviation of Ningxia University is proposed and tested. In this chapter, the feasibility of directed self-assembly of block copolymers based on the heterogeneous nucleation process is systematically confirmed.
Download or read book Self assembly of Block Copolymers and Polymer Brushes written by Wei Wei and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-assembly of block copolymer materials (BCPs) and polymer brushes in the sub-50 nm length scale are explored in this thesis. BCPs and mixed polymer brushes have the ability to self-assemble into well-ordered structures which are ideal for surface patterning, templating and growth of nanomaterials. Compared to the extensively studied morphologies resulting from BCPs, phase behavior of mixed brushes is experimentally less explored, mainly due to the synthetic and characterization challenges. In this thesis we derive from the studies in the BCP self-assembly in thin films to study the melt phase behavior of mixed brushes on a planar substrate. In the first part of the thesis we study the thin film assembly of a strongly phase-separating cylinder forming poly(styrene-b-2 vinylpyridine) (PS-b-P2VP). The cylinders are used to template arrays of sub-20-nm-wide molybdenum disulfide (MoS2) nanowires. In the second part of the thesis we develop a synthetic route to grow uniform, high-grafting density polymer brushes with controlled brush length on planar substrates. This method starting from an initiator coating overcomes all the previous synthetic challenges. This chemistry is first tested by growing a mixed brush poly(methyl methacrylate)/polystyrene (PMMA/PS). We validate for the first time the predicted morphology for mixed brush in melt using the PS/PMMA. The deviation from the expected phase behavior as we move to strongly segregating PS/P2VP mixed brush system is discussed. Lessons learned from the thin film assembly of the PS-b-P2VP in the first part of the thesis led to the largely unexplored area of chain-end effects on morphology in mixed polymer brushes. Potential solutions towards the self-assembly of PS/P2VP mixed bushes in melt is discussed. Three major contributions are made in this thesis: 1) development of an universal method to synthesize A/B mixed brushes with uniform grafting of A/B chains; 2) development of a model to experimentally evaluate the grafting densities of the two brushes; and 3) discovery of chain end effect on thermal stability of mixed brushes and its influence on the morphology. This thesis paves the way for synthesizing mixed brushes with unprecedented level of control, hence opening up new phase behavior and potential surface patterning methods.
Download or read book Block Copolymer Self assembly written by Gayashani Kanchana Ginige and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular self-assembly is the basis of structure in nature. While of far less complexity than a natural system, the same physical rules apply to simple synthetic designed systems that spontaneously form self-assembled structures and patterns. The self-assembly of block copolymers (BCPs) is an interesting example, as it can be harnessed to form both 2D (in thin films) and 3D (in bulk) porous and chemically controlled morphologies at scale. The self-assembly of BCPs on surfaces is of interest for a range of applications, but due to the enormous economic driver that is the computer industry, this direction has been pushed most strongly. Self-assembly of BCPs has been described in the International Technology Roadmap for Semiconductors (the ITRS, and now the IDRS) for almost two decades for lithography on semiconductors and for patterning the magnetic material of hard drives. As a result, there has been much academic interest, both fundamental and applied, to meet the challenges as outlined in the ITRS/IDRS due to the promise of this scalable and low-cost nanopatterning approach. More recently, the remarkable work harnessing BCP self-assembly has been directed to other applications, one being optical metamaterials; this thesis will add to this growing body of science. One aspect holding BCP self-assembly back is the defectivity in the patterned material or surface; some applications are more defect tolerant than others, but hard drive and other computer-industry applications have very low tolerance for defects. It is, therefore, important to have systematic control over the self-assembly process as well as quality of the final patterns generated by BCP self-assembly for these applications and others not yet imagined. This thesis examines the defectivity of the hexagonal nanoscale patterns derived from BCP self-assembly and looks at extending them to produce nanoscale patterns of native and non-native morphologies that have plasmonic properties. This thesis is divided into two parts. The first part deals with optimization of solvent vapor annealing of BCP self-assembly, the critical step in which the actual nanoscale phase segregation takes place; in this case, it uses a controlled solvent vapor flow annealing apparatus, design of experiment and machine learning approaches. In this work, it was discovered that slight variations in the initial film thickness on the order of even a couple of nanometers and the final swelling degree have a huge influence on the defectivity and the quality of the resulting patterns. Next, machine learning approaches are applied to compile qualitative and quantitative defect analysis into a single figure of merit that is mapped across an experimental parameter space. This approach enables faster convergence of results to arrive at the optimum annealing conditions for the annealing of thin films of BCPs of PS-b-PDMS that generate nanoscale hexagonal patterns of silica dots with a minimum number of defects. In the second part of the thesis, mixed metal/oxide double layer patterning was studied using sequential self-assembly of BCPs. The second part of the thesis starts with optimization of reactive ion etching (RIE) for producing single layer metal nanopatterns from metal ion-loaded thin films of PS-b-P2VP BCPs to generate single layers of hexagonal metal nanopatterns that can withstand a second consecutive reactive ion etching step. The goal of this work is to enable density doubled and/or Moiré pattern formation via self-assembly of a second layer of BCP on the initial pattern prepared by self assembly of either the same or different BCP, as will be described in Chapter 4. Therefore, the initial pattern produced via BCP self-assembly and RIE etching would need to withstand a second treatment step of BCP self-assembly and RIE. While single layer nanopatterns of Au and Pt nanoparticles can be produced without much trouble, these resulting patterns could not be applied for density multiplication of metal-metal nanopatterns since the metal dots become too small and disordered. To demonstrate that metal nanoparticles derived from BCPs could be used, at least, to produce a mixed metal oxide/metal patterns, arrays of SiOx dots were first produced from PS-b-PDMS BCPs and then layered a BCP of PS-b-P2VP that was subsequently loaded with gold or platinum ions. Upon RIE etching, the BCP is removed and the SiOx/Au or Pt nanoparticle arrays were produced. Based upon the outcomes of the optimization of the etching work, mixed Au-Pt commensurate and incommensurate hexagonal lattice patterns were produced on both silicon and quartz substrates. Finally, the optical properties of these mixed metal Pt-Au bilayer patterns were studied. They demonstrated interesting plasmonic properties of the bilayer patterns, including consistent observation of extended plasmon bands that suggest coupling of the localized surface plasmon resonances (LSPRs) of the gold nanoparticles through proximal platinum nanoparticles when arrayed in periodic patterns.
Download or read book Directed Self assembly of Block Copolymer Thin Films From Fundamentals Science to Applications written by and published by . This book was released on 2014 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Chapter 4, the alignment of block copolymer domains in tapered width channels has been studied. Confined polymer chains undergo elastic deformation to satisfy the channel width constraint and narrow end of the channel imparts a stronger directing field on the alignment of block copolymer domains.
