Block copolymer based nanostructures: materials, processes, and applications to electronics.
IBM1
TL;DR: A comparison study of how three different approaches to placement control of block Copolymer Ordering in Thin Films changed the quality of the films they produced.
Abstract: 2.4. Block Copolymer Containing Hybrids 151 3. Block Copolymer Ordering in Thin Films 153 3.1. General Process Steps 153 3.2. Morphology of Thin Films 154 3.3. Thickness-Dependent Nanopatterning 154 3.3.1. Ultrathin Films: Monomolecular Films 155 3.3.2. Sub-L0 Thick Films 155 3.3.3. Thick Films 157 3.4. Placement Control: Directed Self-Assembly (DSA) 162 3.4.1. Topographic Guiding Patterns: Graphoepitaxy 163
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1,100 citations
TL;DR: This Review illustrates recent progress in the field of block copolymer materials by highlighting selected emerging applications by highlightingselected emerging applications.
Abstract: Recent advances in polymer synthesis have significantly enhanced the ability to rationally design block copolymers with tailored functionality. The self-assembly of these macromolecules in the solid state or in solution allows the formation of nanostructured materials with a variety of properties and potential functions. This Review illustrates recent progress in the field of block copolymer materials by highlighting selected emerging applications.
600 citations
TL;DR: In this article, the current state of block copolymer lithography and key challenges and opportunities within the field are discussed, focusing on advances and issues related to thermal annealing.
Abstract: This Perspective addresses the current state of block copolymer lithography and identifies key challenges and opportunities within the field. Significant strides in experimental and theoretical thin film research have nucleated the transition of block copolymers “from lab to fab”, but outstanding questions remain about the optimal materials, processes, and analytical techniques for first-generation devices and beyond. Particular attention herein is focused on advances and issues related to thermal annealing. Block copolymers are poised to change the traditional lithographic resolution enhancement paradigm from “top-down” to “bottom-up”.
511 citations
TL;DR: In this paper, the authors provide a critical analysis of the current knowledge concerning solvent vapor annealing (SVA) of block polymer thin films and identify key challenges that will be important to overcome for future development of SVA as a practical, reliable, and universal technique for the valorization of block polymers in a wide range of technologies.
Abstract: This Perspective provides a critical analysis of the current knowledge concerning solvent vapor annealing (SVA) of block polymer thin films. Herein, we identify key challenges that will be important to overcome for future development of SVA as a practical, reliable, and universal technique for the valorization of block polymer thin films in a wide range of technologies. The Perspective includes a brief background on thin film block polymer self-assembly, a historical account of the SVA technique, an overview of the SVA fundamentals that are necessary to develop a more comprehensive picture of the overall process, and summaries of relevant and important contributions from the recent literature. We also offer our outlook on SVA and suggest important future directions.
481 citations
TL;DR: The use of o-nitrobenzyl group (o-NB) in polymer chemistry has been extensively studied in this article, including the use of O-NB-based cross-linkers for photodegradable hydrogels, o-NB side chain functionalization in (block) copolymers, and oNB functionalization for thin film patterning for self-assembled monolayers.
Abstract: Polymers featuring photolabile groups are the subject of intense research because they allow the alteration of polymer properties simply by irradiation. In particular, the o-nitrobenzyl group (o-NB) is utilized frequently in polymer and materials science. This Perspective pays particular attention to the increasing utilization of this chemical group in polymer chemistry. It covers the use of (i) o-NB-based cross-linkers for photodegradable hydrogels, (ii) o-NB side chain functionalization in (block) copolymers, (iii) o-NB side chain functionalization for thin film patterning, (iv) o-NB for self-assembled monolayers, (v) photocleavable block copolymers, and (vi) photocleavable bioconjugates. We conclude with an outlook on new research directions in this rapidly expanding area.
456 citations
References
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TL;DR: In this paper, the synthesis of mesoporous inorganic solids from calcination of aluminosilicate gels in the presence of surfactants is described, in which the silicate material forms inorganic walls between ordered surfactant micelles.
Abstract: MICROPOROUS and mesoporous inorganic solids (with pore diameters of ≤20 A and ∼20–500 A respectively)1 have found great utility as catalysts and sorption media because of their large internal surface area. Typical microporous materials are the crystalline framework solids, such as zeolites2, but the largest pore dimensions found so far are ∼10–12 A for some metallophosphates3–5 and ∼14 A for the mineral cacoxenite6. Examples of mesoporous solids include silicas7 and modified layered materials8–11, but these are invariably amorphous or paracrystalline, with pores that are irregularly spaced and broadly distributed in size8,12. Pore size can be controlled by intercalation of layered silicates with a surfactant species9,13, but the final product retains, in part, the layered nature of the precursor material. Here we report the synthesis of mesoporous solids from the calcination of aluminosilicate gels in the presence of surfactants. The material14,15 possesses regular arrays of uniform channels, the dimensions of which can be tailored (in the range 16 A to 100 A or more) through the choice of surfactant, auxiliary chemicals and reaction conditions. We propose that the formation of these materials takes place by means of a liquid-crystal 'templating' mechanism, in which the silicate material forms inorganic walls between ordered surfactant micelles.
15,125 citations
TL;DR: Block copolymers are macromolecules composed of sequences, or blocks, of chemically distinct repeat units that make possible the sequential addition of monomers to various carbanion-ter minated ("living") linear polymer chains.
Abstract: Block copolymers are macromolecules composed of sequences, or blocks, of chemically distinct repeat units. The development of this field originated with the discovery of termination-free anionic polymerization, which made possible the sequential addition of monomers to various carbanion-ter minated ("living") linear polymer chains. Polymerization of just two dis tinct monomer types (e.g. styrene and isoprene) leads to a class of materials referred to as AB block copolymers. Within this class, a variety of molec ular architectures is possible. For example, the simplest combination, obtained by the two-step anionic polymerization of A and B monomers, is an (A-B) dioblock copolymer. A three-step reaction provides for the preparation of (ABA) or (BAB) triblock copolymer. Alternatively, "living" diblock copolymers can be reacted with an n-functional coupling agent to produce (A-B)n star-block copolymers, where n = 2 constitutes a triblock copolymer. Several representative (A-B)n block copolymer architectures
3,475 citations
3,434 citations
TL;DR: The Knitting Pattern as mentioned in this paper is a block copolymer that was discovered by Reimund Stadler and his coworkers and reflects a delicate free-energy minimization that is common to all blockcopolymer materials.
Abstract: Block copolymers are all around us, found in such products as upholstery foam, adhesive tape and asphalt additives. This class of macromolecules is produced by joining two or more chemically distinct polymer blocks, each a linear series of identical monomers, that may be thermodynamically incompatible (like oil and vinegar). Segregation of these blocks on the molecular scale (5–100 nm) can produce astonishingly complex nanostructures, such as the “knitting pattern” shown on the cover of this issue of PHYSICS TODAY. This striking pattern, discovered by Reimund Stadler and his coworkers, reflects a delicate free‐energy minimization that is common to all block copolymer materials.
2,824 citations
TL;DR: A simple, robust, chemical route to the fabrication of ultrahigh-density arrays of nanopores with high aspect ratios using the equilibrium self-assembled morphology of asymmetric diblock copolymers is shown.
Abstract: We show a simple, robust, chemical route to the fabrication of ultrahigh-density arrays of nanopores with high aspect ratios using the equilibrium self-assembled morphology of asymmetric diblock copolymers. The dimensions and lateral density of the array are determined by segmental interactions and the copolymer molecular weight. Through direct current electrodeposition, we fabricated vertical arrays of nanowires with densities in excess of 1.9 x 10(11) wires per square centimeter. We found markedly enhanced coercivities with ferromagnetic cobalt nanowires that point toward a route to ultrahigh-density storage media. The copolymer approach described is practical, parallel, compatible with current lithographic processes, and amenable to multilayered device fabrication.
2,106 citations