Block copolymer lithography is a promising method for fabricating periodical nanopatterns of less than 20 nm by self-assembly and can be applicable for fabricating patterned magnetic media with a recording density over 1 Tb/in.2. We found a simple technique to control the orientation of cylindrical microdomains in thin films. Simply by mixing polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymers with the homopolymer (PS or PMMA) of the major component, we could align the cylindrical microdomains perpendicular to the film surface. The added homopolymer induces conformational entropic relaxation of the block chains in microdomain space and stabilizes the perpendicular orientation of hexagonally packed cylindrical microdomains. Thus formed perpendicular cylinders can be readily aligned in a regular array with a grating substrate.
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Adv Mater
June 2024
Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
Fluorescent organic nanoparticles (NPs) with exceptional brightness hold significant promise for demanding fluorescence bioimaging applications. Although considerable efforts are invested in developing novel organic dyes with enhanced performance, augmenting the brightness of conventional fluorophores is still one of the biggest challenges to overcome. This study presents a supramolecular strategy for constructing ultrabright fluorescent nanoparticles in aqueous media (referred to as "Supra-fluorophores") derived from conventional fluorophores.
View Article and Find Full Text PDFACS Macro Lett
January 2024
National Creative Research Initiative Center for Hybrid Nano Materials by High-Level Architectural Design of Block Copolymer, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, Republic of Korea.
An A(AB) dendron-like miktoarm star copolymer consisting of polystyrene (PS, A) and poly(2-vinylpyridine) (P2VP, B) was synthesized using a series of anionic polymerization, atom-transfer radical polymerization (ATRP), and click reaction. The morphology of A(AB) changed greatly depending on the volume fraction of A and the chain asymmetry. Interestingly, a body-centered cubic spherical phase was found even at = 0.
View Article and Find Full Text PDFACS Macro Lett
July 2023
National Creative Research Initiative Center for Hybrid Nano Materials by High-level Architectural Design of Block Copolymer, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, Republic of Korea.
Hexagonally packed (HEX) cylindrical microdomains can be obtained through the self-assembly of block copolymers (BCPs) with a moderately asymmetric volume fraction of one block (), resulting in the formation of minor cylinders. However, for next-generation lithography and high-density memory devices, it is desirable to obtain densely and tetragonally packed inverted cylindrical microdomains, which are composed of the major block in the minor matrix. The inverted cylinders differ from conventional HEX cylinders, which consist of the minor block in the matrix of the major block.
View Article and Find Full Text PDFACS Nano
May 2023
Polymer Science and Engineering Department, University of Massachusetts, Amherst, Massachusetts 01003, United States.
Upon exposure to UV light (120 mW/cm, λ = 365 nm), a - isomerization occurs in a cylinder-forming, azobenzene-containing block copolymer of polydimethylsiloxane--poly((4(phenyldiazenyl)phenoxy)hexyl acrylate) (PDMS--PPHA) that enables the generation of monodomains of healable, long-range ordered arrays of nanoscopic domains over macroscopic distances. The - isomerization gives rise to a significant increase in the dielectric constant (from 6.52 to 19.
View Article and Find Full Text PDFNanoscale
February 2023
School of Chemical and Biological Engineering, Seoul National University, Seoul 08826, Republic of Korea.
Transition metal dichalcogenides (TMDs), , MoS, MoSe, ReS, and WSe, are effective materials for advanced optoelectronics owing to their intriguing optical, structural, and electrical properties. Various approaches for manipulating the surface of the TMDs have been suggested to unleash the optoelectronic potential of the TMDs. Herein, we employed the self-assembly of the poly(styrene--methyl methacrylate) (PS--PMMA) block copolymer (BCP) to prepare a nanoporous pattern and generate nanostructured charge-transfer p-doping on the WSe surface, maximizing the depletion region in the absorber layer.
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