Author: Wubin Bai Publisher: ISBN: Category : Languages : en Pages : 136
Book Description
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.
Author: Monali N. Basutkar Publisher: ISBN: Category : Block copolymers Languages : en Pages : 237
Book Description
The aggressive miniaturization of nanoelectronic devices poses a pressing challenge in using conventional patterning technologies that are fast approaching their intrinsic resolution limits. Molecular self-assembling block copolymers (BCPs) are promising candidates for integrating and extending the current photolithographic constraints, facilitating the fabrication of next-generation nanotemplating materials via directed self-assembly. The current work focuses on the development of viable dynamic self-assembly strategies for achieving highly ordered versatile BCP nanostructures with precise feature size control and registration, as well as provides insights into the fundamentals of BCP thin film self-assembly driven by dynamic annealing fields A continuous template-free method toward rapid fabrication (2-4 minutes) of highly ordered through-thickness vertical lamellar polystyrene-block-poly(methyl methacrylate) l-PS-b-PMMA) microdomains in l-BCP films on quartz (silicon oxide) substrate was developed. A molecular relaxation induced vertical l-BCP ordering occurs under a transient macroscopic vertical strain field, imposed by a high film thermal expansion rate under sharp thermal gradient cold zone annealing (CZA-S). The high thermal gradient had to be selectively tuned with the CZA-S sweep rates for controlling the polymer chain relaxation dynamics for vertical order. Comparable conventional static thermal annealing of identical l-BCP films using vacuum oven failed to induce the desired nanostructure. Morphology evolution tracked in real time along the CZA-S thermal gradient profile using in situ grazing incidence small angle x-ray scattering (GISAXS) demonstrated four regimes of ordering: microphase separation from a quenched-disordered state (Regime 1), initial formation of vertical lamellae due to the sharp thermal gradient imposed on the l-BCP film (Regime 2), polygrain structure resulting from the broad [del] T region around Tmax (Regime 3), and an ultimate highly vertically ordered l-BCP morphology due to grain coarsening on the cooling edge (Regime 4). A detailed examination of the influence of CZA process parameters such as temperature gradient field strength ([del] T) of the thermal annealing profile, sweep velocity (v) and the corresponding annealing time (t) on the mechanism and dynamics of l-BCP ordering was performed. The complex interplay between thermodynamic equilibrium, surface and interfacial energies, confinement effects and BCP ordering kinetics was also investigated to determine the effect of BCP film attributes on morphological development. By tuning the CZA-S process dynamics with the l-BCP relaxation timescales, this process created vertical l-BCP nanodomains with controlled feature sizes via molecular weight control. Besides regulating the out-of-plane nanostructure orientation, the alignment of BCP microdomains in-plane was locally tuned by biasing the BCP assembly energetics using an edge-templating strategy. The relaxation of residual stresses and minimization of chain distortion energy penalties along the film boundary were the factors governing the edge-templating mechanism that spontaneously aligns the BCP microdomains orthogonal to the film-discontinuity. Both, kinetic and thermodynamic factors were associated with the boundary-propagation effect. This research demonstrates a new paradigm for advancement of BCP nanotemplating and nanolithography applications due to its potential to fabricate user-defined hierarchical micro-nanopatterns.
Author: Karim Raafat Gadelrab Publisher: ISBN: Category : Languages : en Pages : 140
Book Description
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.
Author: Ian W. Hamley Publisher: Oxford University Press on Demand ISBN: 9780198502180 Category : Science Languages : en Pages : 424
Book Description
This comprehensive and systematic text is the first of its kind to deal with the fundamental physics underlying the remarkable structural and dynamical properties of block copolymers. It provides the polymer scientist and technologist with a firm grounding in the principles underlying the wide applications of these important materials. It also highlights the intrinsically fascinating properties of block copolymers, such as nanoscale self-assembly in bulk and two-dimensions. The first textof its kind on the subject since the mid-1980s, this book stands alone - previous texts have focused on the chemical and material properties of block copolymers. During the last decade, there have been major developments in the field, and these experimental and theoretical advances are discussed in depth. Topics covered include: the thermodynamics and dynamics of block copolymer melts, block copolymers in dilute, semidilute and concentrated solutions, the structure of crystalline block copolymers and block copolymers in blends with other polymers. This informative book is essential to the polymer physics and materials science researcher in industry and academia, and postgraduates in related fields. Final year undergraduate students in chemistry, physics and materials science will also find this book useful as a reference text.
Author: Roel Gronheid Publisher: Woodhead Publishing ISBN: 0081002610 Category : Technology & Engineering Languages : en Pages : 328
Book Description
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
Author: Katsuhiko Ariga Publisher: Elsevier ISBN: 0323994733 Category : Technology & Engineering Languages : en Pages : 648
Book Description
Materials Nanoarchitectonics: From Integrated Molecular Systems to Advanced Devices provides the latest information on the design and molecular manipulation of self-organized hierarchically structured systems using tailor-made nanoscale materials as structural and functional units. The book is organized into three main sections that focus on molecular design of building blocks and hybrid materials, formation of nanostructures, and applications and devices. Bringing together emerging materials, synthetic aspects, nanostructure strategies, and applications, the book aims to support further progress, by offering different perspectives and a strong interdisciplinary approach to this rapidly growing area of innovation. This is an extremely valuable resource for researchers, advanced students, and scientists in industry, with an interest in nanoarchitectonics, nanostructures, and nanomaterials, or across the areas of nanotechnology, chemistry, surface science, polymer science, electrical engineering, physics, chemical engineering, and materials science. - Offers a nanoarchitectonic perspective on emerging fields, such as metal-organic frameworks, porous polymer materials, or biomimetic nanostructures - Discusses different approaches to utilizing "soft chemistry" as a source for hierarchically organized materials - Offers an interdisciplinary approach to the design and construction of integrated chemical nano systems - Discusses novel approaches towards the creation of complex multiscale architectures
Author: Anbanandam Parthiban Publisher: John Wiley & Sons ISBN: 1118860489 Category : Technology & Engineering Languages : en Pages : 408
Book Description
Understanding the reactivity of monomers is crucial in creating copolymers and determining the outcome of copolymerization. Covering the fundamental aspects of polymerization, Synthesis and Applications of Copolymers explores the reactivity of monomers and reaction conditions that ensure that the newly formed polymeric materials exhibit desired properties. Referencing a wide-range of disciplines, the book provides researchers, students, and scientists with the preparation of a diverse variety of copolymers and their recent developments, with a particular focus on copolymerization, crystallization, and techniques like nanoimprinting and micropatterning.
Author: Li Yao Publisher: ISBN: Category : Block copolymers Languages : en Pages : 150
Book Description
This dissertation explores the use of block copolymers which can self-assemble into different morphologies as templates to fabricate nanostructured materials. The first section (Chapters 2-4) reports the formation of mesoporous silica films with spherical, cylindrical and bicontinuous pores up to 40 nm in diameter through replicating the morphologies of the solid block copolymer (BCP) templates, polystyrene-b-poly(tert-butyl acrylate) (PS-b-PtBA), via phase selective condensation of tetraethylorthosilicate in supercritical CO2. Next, directed self-assembly was used to control the orientation of cylindrical domains in PS-b-PtBA templates. Large-area aligned mesochannels in silica films with diameters tunable between 5 and 30 nm were achieved through the replication of oriented templates via scCO2 infusion. The long-range alignment of mesochannels was confirmed through GISAXS with sample stage azimuthal rotation. In the second section (Chapters 5-6), enantiopure tartaric acid was used as an additive to dramatically improve ordering in poly(ethylene oxide-block-tert-butyl acrylate) (PEO-b-PtBA) copolymers. Transmission electron microscopy (TEM), atomic force microscopy (AFM) and X-ray scattering were used to study the phase behavior and morphologies within both bulk and thin films. With the addition of a photo acid generator, photo-induced disorder in the PEO-b-PtBA/tartaric acid composite system was achieved upon UV exposure which deprotected the PtBA block to yield poly(acrylic acid) (PAA), which is phase-miscible with PEO. Area-selective UV exposure using a photo-mask was applied with the assistance of trace amounts of base quencher to achieve high-resolution hierarchical patterns. Helical superstructures were observed by TEM in this BCP/chiral additive system with 3D handedness confirmed by TEM tomography. In the last section (Chapter 7), ultra-high loadings of nanoparticles into target domains of block copolymer composites were achieved by blending the block copolymer hosts with small molecule additives that exhibit strong interactions with one of the polymer chain segments and with the nanoparticle ligands via hydrogen bonding. The addition of 40 wt% D-tartaric acid to poly(ethylene oxide-block-tert-butyl acrylate) (PEO-b-PtBA) enabled the loading of up to 150 wt% of 4-hydroxythiophenol functionalized Au nanoparticles relative to the mass of the target hydrophilic domain. This was equivalent to over 40% Au by mass of the resulting well ordered composite as measured by thermal gravimetric analysis.
Author: Li-Chen Cheng (Ph.D.) Publisher: ISBN: Category : Languages : en Pages : 188
Book Description
Self-assembly of block copolymers (BCPs) is emerging as a promising route for numerous technological applications to fabricate a variety of nanoscopic structures. The resulting feature sizes range from a few to several hundred nanometers, and are readily tunable by varying the molecular weights of block copolymers. Directed self-assembly of block copolymer is an effective way to pattern periodic arrays of features with long-range order, to generate complex patterns, and to multiplicatively increase the pattern density and resolution that are far beyond the limit of conventional lithography. Despite of the significant progress in the area of directed self-assembly in recent years, critical research problems regarding the dimension scalability toward sub-10-nm regime and large feature sizes on hundreds of nanometers scale as well as the capability of generating complex device-oriented patterns remain challenging. In this thesis, BCP systems, including high-v BCPs that are capable of self-assembling into extreme small and large feature sizes as well as those with more complex block architectures, are identified and studied in order to understand how those materials may be processed and directed selfassembly to bridge the patterning size spectrum between nano- and micro-fabrication. Another focus is placed on the scientific exploration of directed self-assembly of triblock terpolymers and the investigation on the mechanisms that regulate the scaling and geometry of self-assembled patterns. A comprehensive understanding about self-assembly of BCP thin films will enable developing device-oriented geometries, manipulating BCPs phase behavior, and incorporating new functional materials for a wider range of applications. In the meanwhile, optimizing the processing condition of self-assembly of various BCPs is essential to confirm viability of the directed self-assembly of block copolymers process in manufacturing.
Author: B.-L. Su Publisher: John Wiley & Sons ISBN: 3527639594 Category : Technology & Engineering Languages : en Pages : 676
Book Description
This first book devoted to this hot field of science covers materials with bimodal, trimodal and multimodal pore size, with an emphasis on the successful design, synthesis and characterization of all kinds of hierarchically porous materials using different synthesis strategies. It details formation mechanisms related to different synthesis strategies while also introducing natural phenomena of hierarchy and perspectives of hierarchical science in polymers, physics, engineering, biology and life science. Examples are given to illustrate how to design an optimal hierarchically porous material for specific applications ranging from catalysis and separation to biomedicine, photonics, and energy conversion and storage. With individual chapters written by leading experts, this is the authoritative treatment, serving as an essential reference for researchers and beginners alike.
Author: Wubin Bai
Author: Monali N. Basutkar
Author: Karim Raafat Gadelrab
Author: Ian W. Hamley
Author: Roel Gronheid
Author: Katsuhiko Ariga
Author: Anbanandam Parthiban
Author: Li Yao
Author: Li-Chen Cheng (Ph.D.)
Author: B.-L. Su