Download or read book Controlled Self assembly of Gyroid forming Block Copolymer Templates for Optical Metamaterials written by Karolina Godlewska and published by . This book was released on 2018 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Gyroid Optical Metamaterials written by James A. Dolan and published by Springer. This book was released on 2018-11-04 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis explores the fabrication of gyroid-forming block copolymer templates and the optical properties of the resulting gyroid optical metamaterials, significantly contributing to our understanding of both. It demonstrates solvent vapour annealing to improve the long-range order of the templates, and investigates the unique crystallisation behaviour of their semicrystalline block. Furthermore, it shows that gyroid optical metamaterials that exhibit only short-range order are optically equivalent to nanoporous gold, and that the anomalous linear dichroism of gyroid optical metamaterials with long-range order is the result of the surface termination of the bulk gyroid morphology. Optical metamaterials are artificially engineered materials that, by virtue of their structure rather than their chemistry, may exhibit various optical properties not otherwise encountered in nature (e.g. a negative refractive index). However, these structures must be significantly smaller than the wavelength of visible light and are therefore challenging to fabricate using traditional “top down” techniques. Instead, a “bottom up” approach can be used, whereby optical metamaterials are fabricated via templates created by the self-assembly of block-copolymers. One such morphology is the gyroid, a chiral, continuous and triply periodic cubic network found in a range of natural and synthetic self-assembled systems.

Download or read book Optical Metamaterials by Block Copolymer Self Assembly written by Stefano Salvatore and published by Springer. This book was released on 2014-07-11 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metamaterials are artificially designed materials engineered to acquire their properties by their specific structure rather than their composition. They are considered a major scientific breakthrough and have attracted enormous attention over the past decade. The major challenge in obtaining an optical metamaterial active at visible frequencies is the fabrication of complex continuous metallic structures with nano metric features. This thesis presents the fabrication and characterization of optical metamaterials made by block copolymer self assembly. This approach allows fabrication of an intriguing and complex continuous 3D architecture called a gyroid, which is replicated into active plasmonic materials such as gold. The optical properties endowed by this particular gyroid geometry include reduction of plasma frequency, extraordinarily enhanced optical transmission, and a predicted negative refractive index. To date, this is the 3D optical metamaterial with the smallest features ever made.

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 Block Copolymer Self assembly as a Template for the Generation of Ordered Arrays of Nanowires written by Thomas Garrett Fitzgerald and published by . This book was released on 2008 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: Upon self-assembly block copolymers (BCP) form a variety of well-ordered nanometer-sized structures in thin films which satisfy the size requirement for many nanotechnologies. This thesis details the in-depth study of three different BCP systems including the various factors which influence the final film structure, the generation of nanoporous polymer templates and their subsequent use a lithographic etch masks. Chapter 1 provides a general introduction to the principles of BCP self-assembly as well as a brief overview of the current state of this continually expanding field. Chapter 2 focuses on microphase separation within cylinder-forming polystyrene-block-polyisoprene-block-polystyrene BCP thin films. Thermal and solvent annealing are both investigated as potential routes to achieve microphase separation. Following a thermal anneal approach ordered cylindrical structures exhibiting excellent long-range order are achieved using directing effects imposed topographically channelled substrates. Control of film thickness within the channelled structures provides a simple method for control of cylinder orientation (parallel or perpendicular). In Chapter 3 macrophase separation is demonstrated in blends of polystyrene and poly(methyl metacrylate) illustrating the importance of the bonding between polymer units in a polystyrene-block-poly(methyl metacrylate) BCP as a requisite for microphase separation. Both cylinder- and lamellar-forming systems are demonstrated with this BCP, depending on the polymer ratio, and the orientation of the structures can be controlled via polymer-substrate interactions. Variation of molecular weight of the BCP provides a simple means of controlling resultant feature sizes. Reactive ion etching provides a rapid route for the generation of polystyrene template structures which can be subsequently used as positive etch mask to produce arrays of silicon lines. The microphase separation within both polystyrene-block-poly(ethylene oxide) BCP and polystyrene-block-poly(ethylene oxide)/polystyrene blend thin films, induced via solvent annealing, is discussed in Chapter 4. Blends of polystyrene homopolymer and polystyrene-block-poly(ethylene oxide) BCP result in a cylindrical structure rather than the predicted lamellar morphology due to the increased amount of polystyrene present. Selection of the appropriate solvent anneal conditions provides a simple means of controlling the orientation of the final structure. Variation of molecular weight again provides excellent control over feature size, however, if it is too low microphase separation will not occur. Reactive ion etching also provides a rapid route for the generation of polystyrene template structures. Chapter 5 provides a general overview of the various techniques used during the course of this thesis as well as providing supplementary information on calculations and BCP synthesis mentioned in previous chapters.

Download or read book Block Copolymer Self assembly and Templating Strategies written by Wubin Bai and published by . This book was released on 2016 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block copolymers microphase separate to form periodic patterns with period of a few nm and above without the need for lithographic guidance. These self-assembled nanostructures have a variety of bulk geometries (alternating lamellae, gyroids, cylinder or sphere arrays, tiling patterns, core-shell structures) depending on the molecular architecture of the polymer and the volume fraction of its blocks. And in thin films, surface interaction and commensurability effect influence the self-assembly and result in more diverse morphologies including hexagonal-packed perforated lamellae, square array of holes. The progress of self-assembly can be tracked in situ using Grazing Incidence Small Angle X-ray Scattering, and the annealed morphology can be revealed in 3D using TEM tomography. Moreover, non-bulk morphologies can be produced, the ordering of the microdomains can be improved and their locations directed using various templates and processing strategies. The blocks can themselves constitute a functional material, such as a photonic crystal, or they can be used as a mask to pattern other functional materials, functionalized directly by various chemical approaches, or used as a scaffold to assemble nanoparticles or other nanostructures. Block copolymers therefore offer tremendous flexibility in creating nanostructured materials with a range of applications in microelectronics, photovoltaics, filtration membranes and other devices.

Download or read book Solvent Vapor Assisted Self Assembly of Patternable Block Copolymers written by Joan K. Bosworth and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Block copolymer self assembly presents a method for patterning and templating applications on the 10-50 nm length scale, a smaller scale than can be easily achieved by photolithography. Here we investigate the use of functionalized polar-nonpolar block copolymers both as photopatternable self-assembling materials and for selective infiltration of one block for patterning. Block copolymer thin films with defect-free self-assembled morphology over large domains combined with careful control of the orientation of the morphology are critical for these patterning applications. Self assembly of block copolymers is facilitated by polymer chain mobility, commonly achieved by heating block copolymer films above the glass transition temperature of the blocks. However, many block copolymer systems, including those discussed here, are thermally incompatible. Swelling in a solvent vapor, called solvent annealing, provides sufficient mobility for self assembly. Solvent annealing proved critical to forming ordered structures of functional polar-nonpolar block copolymer thin films. Thermal instability initially led to limited self assembly of combined topdown/bottom-up block copolymer systems. In this case, photolithographic functionality has been designed into block copolymers, allowing the majority component of a block copolymer to behave as a negative-tone photoresist. Solvent vapor annealing has provided a simple and inexpensive method for allowing the bottom-up self assembly of these top-down photopatternable materials. An additional benefit of solvent annealing is the ability to reversibly tune the morphology formed using the selectivity of different swelling solvents to the two blocks: that is, the choice of solvent for annealing directs the formation of different morphologies in the dried film, here spherical and cylindrical. This behavior is reversible, alternating annealing sessions lead to switching of the morphology in the film. Secondary ordering techniques applied in tandem with solvent annealing can be used to further control the self assembly and give highly ordered block copolymer domains. Here we demonstrate the use of graphoepitaxy to align block copolymer self assembly to patterns in substrates. The combination of block copolymer self assembly with lithographic crosslinking in films was initially pursued to allow precise location of assembled patterns. Taking this behavior a step further, we combine solvent annealing, used to reversibly tune the self-assembled morphology, and lithographic patterning, used to prevent switching in exposed regions. This combined process has provided a method for selectively patterning 100 nm-wide domains of spherical morphology within regions of parallel-oriented cylindrical morphology. We also investigate solvent annealing of a block copolymer blended with a hydrogen bonding material that selectively segregates into the polar block. Blending provides a method of tuning the periodicity upon solvent annealing for self assembly, with morphology control again possible by solvent selectivity. Selective extraction of the blended material forms voids displaying the tunable periodicity, and the pattern is then transferred by templating to inorganic materials.

Download or read book Metamaterial Electromagnetic Wave Absorbers written by Willie J. Padilla and published by Morgan & Claypool Publishers. This book was released on 2022-01-24 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electromagnetic metamaterials are a family of shaped periodic materials which achieve extraordinary scattering properties that are difficult or impossible to achieve with naturally occurring materials. This book focuses on one such feature of electromagnetic metamaterials—the theory, properties, and applications of the absorption of electromagnetic radiation. We have written this book for undergraduate and graduate students, researchers, and practitioners, covering the background and tools necessary to engage in the research and practice of metamaterial electromagnetic wave absorbers in various fundamental and applied settings. Given the growing impact of climate change, the call for innovations that can circumvent the use of conventional energy sources will be increasingly important. As we highlight in Chapter 6, the absorption of radiation with electromagnetic metamaterials has been used for energy harvesting and energy generation, and will help to reduce reliance on fossil fuels. Other applications ranging from biochemical sensing to imaging are also covered. We hope this book equips interested readers with the tools necessary to successfully engage in applied metamaterials research for clean, sustainable energy. This book consists of six chapters. Chapter 1 provides an introduction and a brief history of electromagnetic wave absorbers; Chapter 2 focuses on several theories of perfect absorbers; Chapter 3 discusses the scattering properties achievable with metamaterial absorbers; Chapter 4 provides significant detail on the fabricational processes; Chapter 5 discusses examples of dynamical absorbers; and Chapter 6 highlights applications of metamaterial absorbers.

Download or read book Self assembly of Block Copolymers for Nanopatterning written by Nathanael Lap-Yan Wu and published by . This book was released on 2014 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: The impressive developments in the semiconductor industry over the past five decades have largely been dependent on the ability to continually reduce the dimensions of devices on a chip. However, as critical dimension requirements for these devices approach the limits of photolithography, new fabrication strategies must be introduced for these remarkable advances to continue. One technology listed by the International Technology Roadmap for Semiconductors as a candidate for next-generation nanostructure fabrication is the directed self-assembly of block copolymers. Block copolymers have received significant attention of late for their ability to template large regular arrays of nanostructures with dimensions ranging from 10 to 50 nm. The production of denser sub-10 nm nanostructures is also possible by reducing the size of these polymers, but a reduction of the polymer size also compromises the quality of nanostructures, making small polymers extremely difficult to use. In this thesis, two different patterning approaches are introduced to push the nanostructure density limits possible for a given polymer. In the first, a novel patterning approach involving thin films of bilayer block copolymer domains is used to effectively double the nanostructure density patterned by a given polymer. The technique is successfully applied to different types and sizes of polymer, and can also form highly controlled arrays of patterns with the help of surface topography. By varying different process parameters during the self-assembly or subsequent plasma steps, the dimensions of these density-doubled patterns may be finely-tuned to the desired width and pitch. The surface coverage of these density-doubled nanostructures is also maximized through adjusting the film thickness and parameters in the self-assembly process. Besides using bilayer films, dense arrays of nanostructures may also be patterned using a multi-step patterning approach. In this approach, multiple layers of block copolymer films are subsequently deposited onto the substrate to template nanostructures. Because nanostructures from previous layers contribute to the surface topography, they influence the self-assembly of successive layers and more dense and complex patterns may be produced as a result.

Download or read book Self assembled Patterns of Block Copolymer homopolymer Blends written by Dongsik Park and published by . This book was released on 2008 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many researchers have studied the orientation behavior of block copolymers (BCPs) with the most recent works directed towards nanotechnologies. Self-assembly of block copolymers is very relevant in controlling periodic nanostructures for nanotechnological applications. Nanotechnological applications of BCPs are possible due to their physical properties related to mass and energy transport, as well as mechanical, electrical, and optical properties. These properties provide substantial benefits in nanostructure membranes, nanotemplates, photonic crystals, and high-density information storage media. In many applications, such nanopatterns need to be achieved as ordered and tunable structures. Consequently, the control of orientation of such structures with defect-free ordering on larger length scales still remain as major research challenge in many cases. In addition to their pure block forms, blends of copolymers with other polymers offer productive research areas in relation to nanostructural self-assembly. We prepared well-aligned nanocylinders into block copolymer over the enhanced sample area and scale of height without any external field applications or modification of interaction between the sample and the substrate. Self-assembled 3-dimensional perpendicular cylinder orientation was achieved mainly by blending of minority homopolymer into the blockcopolymer. Thus, this study investigated a spontaneous and simple method for the orientation of perpendicular cylinders in BCP/homopolymer mixtures on a preferential substrate, by increasing the interaction force between the homologous polymer pair at a fixed composition of minority block component. Since the thermodynamical changes have been simply accomplished by the control of incompatibility between the block components, the intrinsic advantages of block copolymer nanopatterning, such as fast and spontaneous 3-dimensional nanopatterning with a high thermodynamic stability and reproducibility, have been completely preserved in this fabrication strategy. By exploiting thermodynamical changes using temperature variation and by blending a homopolymer with well controlled molecular weight, we illustrated that redistribution of homopolymer resulted in a shift of phase boundaries and in the stabilization of well-ordered structures to create new opportunities for nanotechnologies.

Download or read book Block Copolymer Self assembly Fundamentals and Applications in Formulation of Nano structured Fluids written by Biswajit Sarkar and published by . This book was released on 2013 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dispersions of nanoparticles in polymer matrices form hybrid materials that can exhibit superior structural and functional properties and find applications in e. g. thermo-plastics, electronics, polymer electrolytes, catalysis, paint formulations, and drug delivery. Control over the particle location and orientation in the polymeric matrices are essential in order to realize the enhanced mechanical, electrical, and optical properties of the nanohybrids. Block copolymers, composed of two or more different monomers, are promising for controlling particle location and orientation because of their ability to organize into ordered nanostructures. Fundamental questions pertaining to nanoparticle-polymer interfacial interactions remain open and formulate the objectives of our investigation. Particle-polymer enthalpic and entropic interactions control the nanoparticle dispersion in polymer matrices. Synthetic chemical methods for modifying the particle surface in order to control polymer-particle interactions are involved and large scale production is not possible. In the current approach, a physical method is employed to control polymer-particle interactions. The use of commercially available solvents is found to be effective in modifying particle-polymer interfacial interactions. The approach is applicable to a wide range of particle-polymer systems and can thereby enable large scale processing of polymer nanohybrids. The systems of silica nanoparticles dispersed in long-range or short-range self-assembled structures of aqueous poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymers (Pluronics) is considered here. The effect of various parameters such as the presence of organic solvents, pH, and particle size on the block copolymer organization and the ensuing particle-polymer interactions are investigated. Favorable surface interactions between the deprotonated silica nanoparticle and PEO-rich domain facilitate particle incorporation in the cylindrical lyotropic mesophase formed by hydrated PEO-PPO-PEO block copolymer. The amount of nanoparticle dispersed is limited to 10 wt% due to restrictions posed by a combination of thermodynamics and geometry. Incorporation of deprotonated nanoparticles by replacing equal mass of water did not affect the lattice parameter of the hexagonal lyotropic liquid crystalline structures formed by hydrated PEO-PPO-PEO block copolymer. The incorporation of protonated NPs resulted in an increase in the lattice parameter due to stronger nanoparticle-polymer enthalpic interactions. Two dimensional swelling exponent (d ~ Φpolymer-0. 65) suggests that deprotonated nanoparticles are located inside the PEO-rich domains, away from PEO-PPO interfaces. The presence of organic solvents screen the effect of protonated NPs on the lattice parameter of the hexagonal lyotropic liquid crystalline structures formed by hydrated PEO-PPO-PEO block copolymer.

Download or read book Templated Self assembly for Complex Pattern Fabrication written by Jae-Byum Chang and published by . This book was released on 2014 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: The long-term goal of my Ph.D. study has been controlling the self-assembly of various materials using state-of-the-art nanofabrication techniques. Electron-beam lithography has been used for decades to generate nanoscale patterns, but its throughput is not high enough for fabricating sub-10-nm patterns over a large area. Templated block copolymer(BCP) self assembly is attractive for fabricating few-nanometer-scale structures at high throughput. On an unpattermed substrate, block copolymer self-assembly generates dense arrays of lines or dots without long-range order. Fortunately, physical features defined by electron lithography can guide the self-assembly of block copolymer. In our previous work, the orientation of cylindrical phase block copolymer was controlled simply by changing the distance between physical features, and resulting polymer patterns were analyzed by an image analysis program. Here, we first demonstrated high throughput sub-10-nm feature sizes by applying the same approach to a cylindrical morphology 16kg/mol PS-PDMS block copolymer. The half-pitch of the PDMS cylinders of this block copolymer film is 9 nm, so sub-10-nm structures can be fabricated. We also applied the similar approach to a triblock terpolymer to achieve dot patterns with square symmetry. To achieve a more complex pattern, electron-beam induced cross-linking of a block copolymer and second solvent-annealing process was used. By using this method, a line-dot hybrid pattern was achieved. Despite that the block copolymer self-assembly area had been heavily studied, researchers had yet to ascertain how to design nanostructures to achieve a desired target pattern using block copolymers. To address this problem, we developed a modular method that greatly simplifies the nanostructure design, and using this method, we achieved a circuit-like block-copolymer pattern over a large area. The key innovation is the use of a binary set of tiles that can be used to very simply cover the desired patterning area. Despite the simplicity of the approach, by exploiting neighbor-neighbor interactions of the tiles, a complex final pattern can be formed. The vision is thus one of programmability of patterning by using a simple instruction set. This development will thus be of interest to scientists and engineers across many fields involving self-assembly, including biomolecule, quantum-dot or nanowire positioning; algorithmic self-assembly; and integrated-circuit development. We applied this concept - controlling the assembly of materials using nanostructures - to a different material, protein. Single-molecule protein arrays are useful tools for studying biological phenomena at the single-molecule level, but have been developed only for a few specific proteins using the streptavidin-biotin complex as a linker. By using carefully designed gold nanopatterns and cysteine-gold interaction, we developed a process to make single-molecule protein arrays that can be used for patterning a broad range of proteins.

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 Electrochemically Controlled Self assembly of Block Copolymer Nanostructures written by Hany Basam Eitouni and published by . This book was released on 2005 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Self assembly of Block Copolymers Grafted Onto a Flat Substrate Recent Progress in Theory and Simulations Project Supported by the National Natural Science Foundation of China Grant Nos 20990234 20925414 and 91227121 the Program for Changjiang Scholars and Innovative Research Team in University China Grant No IRT1257 the Programme of Introducing Talents of Discipline to Universities China and by the Tianhe No 1 China written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Block copolymers are a class of soft matter that self-assemble to form ordered morphologies on the scale of nanometers, making them ideal materials for various applications. These applications directly depend on the shape and size of the self-assembled morphologies, and hence, a high degree of control over the self-assembly is desired. Grafting block copolymer chains onto a substrate to form copolymer brushes is a versatile method to fabricate functional surfaces. Such surfaces demonstrate a response to their environment, i.e., they change their surface topography in response to different external conditions. Furthermore, such surfaces may possess nanoscale patterns, which are important for some applications; however, such patterns may not form with spun-cast films under the same condition. In this review, we summarize the recent progress of the self-assembly of block copolymers grafted onto a flat substrate. We mainly concentrate on the self-assembled morphologies of end-grafted AB diblock copolymers, junction point-grafted AB diblock copolymers (i.e., Y-shaped brushes), and end-grafted ABA triblock copolymers. Special emphasis is placed on theoretical and simulation progress.

Download or read book The Self assembly of Lamellae forming Block Copolymer for High Resolution Nanolithography written by Zhiwei Sun and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis will be focused on the thin film self-assembly and high resolution nanolithography of lamellae-forming PS-b-P2VP block copolymer. Some of the scientific and engineering problems of block copolymer self-assembly will be studied using the state-of-the-art characterization facilities including AFM, SEM and synchrotron radiation X-ray scattering, pushing forward the application of block copolymer in high resolution nanolithography, storage media, and separation membranes, etc. The first challenge is the design of BCP with small domain spacing, which defines the resolution of BCP nanolithography. Small domain spacing can be achieved by reducing the degree of polymerization, but order-to-disorder transition happens when the critical [chi]N is reached. In this thesis, we will first discuss the disorder-to-order transition of low molecular weight PS-b-P2VP by increasing the [chi] parameter using salt doping. The domain spacing of PS-b-P2VP will be pushed down one step further by design BCPs with star shape chain architecture, achieving lamellar nanostructures with sub-10 nm repeating period. Another challenge that hampers the application of BCP is the defect in the self-assembled BCP thin film. The defects in the thin film reduces the grain sizes of BCP lattices and also brings in new challenges in lithography and pattern transfer, thus the defect density in the self-assembled BCP thin film has to be reduced. It is important to understand how the defects were generated and how it can be removed using annealing and directed self-assembly (DSA). In this thesis, in situ grazing incidence small angle X-ray scattering will be used to characterize the solvent vapor annealing of P2VP-b-PS-b-P2VP triblock copolymer in thin film. The trade-off between the in-plane and out-of-plane defect density was revealed during solvent evaporation. Furthermore, long-range ordered lamellar line patterns were prepared using directed self-assembly on patterned substrate.

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.