Du Yeol Ryu

Interfacial interactions underpin phenomena ranging from adhesion to surface wetting. Here, we describe a simple, rapid, and robust approach to modifying solid surfaces, based on an ultrathin cross-linkable film of a random copolymer, which does not rely on specific surface chemistries. Specifically, thin films of benzocyclobutene-functionalized random copolymers of styrene and methyl methacrylate were spin coated or transferred, then thermally cross-linked on a wide variety of metal, metal oxid

The microdomain orientation in thin films of cylinder- and lamella-forming diblock copolymers, polystyrene- block -poly(methyl methacrylate) (PS- b -PMMA), was investigated as a function of the film thickness and the composition of random copolymers composed of styrene (S) and methyl methacrylate (MMA), denoted as P(S- r -MMA), that were anchored to the substrate. Using scanning force microscopy (SFM) and grazing incidence small-angle X-ray scattering (GISAXS), the dependence of the microdomain

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

The directed assembly of block copolymer nanostructures with large periods exceeding 100 nm remains challenging because the translational ordering of long-chained block copolymer is hindered by its very low chain mobility. Using a solvent-vapor annealing process with a neutral solvent, which was sequentially combined with a thermal annealing process, we demonstrate the rapid evolution of a perpendicularly oriented lamellar morphology in high molecular weight block copolymer films on neutral subs

symmetry, which allows for the symmetrical introduction of self-assembling motifs. This review describes the fabrication of porphyrin-based supramolecular polymers and novel discoveries in supramolecular polymer growth. First, we summarise the (i) design concepts, (ii) growth mechanism and (iii) analytical methods of porphyrin-based supramolecular polymers. Then, the examples of porphyrin-based supramolecular polymers formed by (iv) hydrogen bonding, (v) metal coordination-based interaction, (vi

Nanoporous structures were obtained by the self-assembly of polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) block copolymers (BCP) where, in thick films, cylindrical microdomains were oriented normal to the substrate and air interfaces, and in the interior of the films, the microdomains were randomly oriented. Continuous nanopores that penetrated through the film were readily produced by a simple preferential swelling of the PMMA microdomains. The confined swelling and rapid contraction of P

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), respe

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, respectivel

Abstract 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 PDMS ) 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 PDMS = 0.796 and 0.851, respectively, plausibly due to h

Three-dimensional (3D) nanostructures were obtained by the directed formation of multilayer block copolymer (BCP) thin films. The initial step in this strategy involves the assembly and cross-linking of cylinder-forming polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) BCP, in which 1.5 mol % of reactive azido (-N(3)) groups were randomly incorporated along the styrene backbone. Significantly, assembly of thin films of lamellar-forming BCPs on top of the underlying cross-linked cylindrical lay

The effective interaction parameters, (χ F ) of the homologous series of deuterated polystyrene- block -poly( n -alkyl methacrylate) copolymers (dPS- b -PA n MA) 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 χ F for dPS- b -PA n MA with n = 1 and 6 is a typical decreasing function of temperature, it is shown that χ F for n from 2 to 4 changes to a monotonic increase with temperatu

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