Yonsei University · Materials Science
Professor Du Yeol Ryu's research lab specializes in the design and fabrication of advanced nanostructured materials through block copolymer self-assembly, with a focus on controlling microphase separation for applications in nanofabrication, templating, and functional materials. The lab investigates the thermodynamics and kinetics of block copolymer phase behavior under external stimuli such as pressure and temperature, utilizing advanced scattering techniques and surface characterization. Key research directions include directed self-assembly for large-area, high-order nanostructures, hybrid and inorganic-containing block copolymers for ultra-small feature fabrication, and interfacial engineering to control microdomain orientation. The lab also explores functional block copolymers, including porphyrin-based systems, for applications in sensing, energy conversion, and biomedicine.
Figures are computed from collected data and may differ slightly.
The self-assembly of block copolymers (BCPs) is emerging as a promising route for numerous applications to generate templates and scaffolds for the fabrication of nanostructured materials. Here, we present an overview of recent progress in the directed self-assembly of BCPs with a focus on guiding the assemblies of extreme (small and large) features over large areas. We introduce inorganic-containing hybrid BCPs that enable access to ultra-small feature sizes. To achieve the desired orientation
Porphyrin derivatives are ubiquitous in bio-organisms and are associated with proteins that play important biological roles, such as oxygen transport, photosynthesis, and catalysis. Porphyrins are very fascinating research objects for chemists, physicists, and biologists owing to their versatile chemical and physical properties. Porphyrin derivatives are actively used in various fields, such as molecular recognition, energy conversion, sensors, biomedicine, and catalysts. Porphyrin derivatives c
The effect of hydrostatic pressure (P) on closed-loop phase behavior of deuterated polystyrene-block-poly(n-pentyl methacrylate) copolymers [dPS-PnPMA] was investigated by using small-angle neutron scattering and birefringence. For P<20.7 bar, dPS-PnPMA exhibited a lower disorder-to-order transition temperature (T(LDOT)) at 175 degrees C, and then an upper order-to-disorder transition temperature (T(UODT)) at 255 degrees C. With increasing pressure both T(LDOT) and T(UODT) were markedly changed,
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTCylindrical Microdomain Orientation of PS-b-PMMA on the Balanced Interfacial Interactions: Composition Effect of Block CopolymersDu Yeol Ryu*, Sujin Ham, Eunhye Kim, Unyong Jeong, Craig J. Hawker§, and Thomas P. Russell⊥View Author Information† Department of Chemical Engineering‡ Department of Materials Science and Engineering and Active Polymer Center for Pattern Integration Yonsei University, Seoul 120-749, Korea§ Material Research Laboratory and Depart
Ultrathin films of benzocyclobutene (BCB)-functionalized random copolymer with styrene and methyl methacrylate, P(S-r-BCB-r-MMA), with thicknesses ranging from 0 to 10.5 nm, were thermally cross-linked on Si substrates. The penetration of deuterated PMMA (dPMMA) into the P(S-r-BCB-r-MMA) films and the microdomain orientation of PS-b-PMMA diblock copolymers on P(S-r-BCB-r-MMA) coated substrates were investigated by neutron reflectivity (NR) and scanning force microscopy (SFM), respectively. NR me
The phase behavior of deuterated polystyrene-block-poly(n-pentyl methacrylate) copolymers (dPS−PnPMA) was investigated by using small-angle X-ray (SAXS) and neutron (SANS) scatterings and rheology. This block copolymer exhibited a closed-loop type of phase behavior as did hydrogenated PS−PnPMA copolymers. The closed loop consists of two transitions: lower disorder-to-order transition (LDOT) and upper order-to-disorder transition (UODT) occurring at a lower and higher temperature, respectively. T
In the search for the formation of Frank-Kasper phases from diblock copolymer self-assembly, a series of compositionally asymmetric poly(dimethylsiloxane)-b-poly(2,2,2-triflouroethyl acrylate)s (PDMS-b-PTFEAs) are synthesized to produce PDMS-rich phases with PDMS volume fractions (f<sub>PDMS</sub> ) ranging from 0.746 to 0.869. As determined by small-angle X-ray scattering analysis, the Frank-Kasper σ and C14 phases are identified at f<sub>PDMS</sub> = 0.796 and 0.851, respectively, plausibly du
The effective interaction parameters, (χF) of the homologous series of deuterated polystyrene-block-poly(n-alkyl methacrylate) copolymers (dPS-b-PAnMA) from methyl (n = 1) to hexyl (n = 6) side groups have been investigated by small-angle neutron scattering and a Hartree (fluctuation correction) analysis. While χF for dPS-b-PAnMA with n = 1 and 6 is a typical decreasing function of temperature, it is shown that χF for n from 2 to 4 changes to a monotonic increase with temperature, revealing grow
We propose a new approach to fluorine-containing, high-χ styrenic block copolymers (BCPs) via side-chain modification in one block. Polystyrene-b-poly(2,2,2-trifluoroethyl acrylate)s (PS-b-PTFEAs) were synthesized by high-conversion transesterification in acrylate units of polystyrene-b-poly(tert-butyl acrylate)s (PS-b-PtBAs) with the narrow dispersity being unchanged. A simple modification from PtBA into PTFEA block effectuates a remarkable increase in Flory–Huggins interaction parameter (χ) be
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