Joona Bang

The self-asembly of block copolymers is a promising platform for the "bottom-up" fabrication of nanostructured materials and devices. This review covers some of the advances made in this field from the laboratory setting to applications where block copolymers are in use.

Improving membrane durability associated with fouling and chlorine resistance remains one of the major challenges in desalination membrane technology. Here, we demonstrate that attractive features of graphene oxide (GO) nanosheets such as high hydrophilicity, chemical robustness, and ultrafast water permeation can be harnessed for a dual-action barrier coating layer that enhances resistance to both fouling and chlorine-induced degradation of polyamide (PA) thin-film composite (TFC) membranes whi

Molecular layer-by-layer (mLbL) assembled thin-film composite membranes fabricated by alternating deposition of reactive monomers on porous supports exhibit both improved salt rejection and enhanced water flux compared to traditional reverse osmosis membranes prepared by interfacial polymerization. Additionally, the well-controlled structures achieved by mLbL deposition further lead to improved antifouling performance. As a service to our authors and readers, this journal provides supporting inf

The self-assembly of triblock copolymers of poly(ethylene oxide-b-methyl methacrylate-b-styrene) (PEO-b-PMMA-b-PS), where PS is the major component and PMMA and PEO are minor components, provides a robust route to highly ordered, nanoporous arrays with cylindrical pores of 10-15 nm that show promise in block copolymer lithography. These ABC triblock copolymers were synthesized by controlled living radical polymerization, and after solvent annealing, thin films showing defect-free cylindrical mic

An asymmetric poly(styrene- b -isoprene) diblock copolymer with block molecular weights of 13 000 and 71 000 g/mol, respectively, was dissolved at 1 vol % in a series of solvents with varying selectivity for styrene: dibuthyl phthalate (DBP), diethyl phthalate (DEP), and dimethyl phthalate (DMP). The degree of solvent selectivity was adjusted by mixing DBP/DEP and DEP/DMP in various proportions. With increasing solvent selectivity, the predominant micellar shape changes from spheres to cylinders

A new crosslinking system based on azide-functionalized random copolymers has been defined for the preparation of substrates with controllable surface interactions. The azido group is used for both thermal- and photo-crosslinking, which is found to be very efficient. Furthermore, the use of UV irradiation for crosslinking enables the preparation of patterned surfaces by conventional photolithographic techniques, combining the “bottom-up” self-assembly of block copolymer strategies with tradition

Various biophysical and biochemical factors are important for determining the fate of neural stem cells (NSCs). Among biophysical signals, topographical stimulation by micro/nanopatterns has been applied to control NSC differentiation. In this study, we developed a hierarchically patterned substrate (HPS) platform that can synergistically enhance the differentiation of human NSCs (hNSCs) by simultaneously providing microscale and nanoscale spatial controls to facilitate the alignment of the cyto

Solvent cast diblock and triblock copolymer films of poly(ethylene oxide- b -styrene) (PEO- b -PS) and poly(ethylene oxide- b -methyl methacrylate- b -styrene) (PEO- b -PMMA- b -PS), with cylindrical microdomains of PEO or PMMA−PEO, have a high degree of lateral ordering after solvent annealing. The relative humidity of the vapor during the solvent annealing has been shown to play an important role in achieving this order. After solvent annealing under high humidity a PEO- b -PMMA- b -PS tribloc

Micropatterns with a high stability, definition, and resolution are an absolute requirement in advanced display technology. Herein, patternable perovskite nanocrystals (PNCs) with excellent stability were prepared by exchanging pristine ligands with multifunctional polymer ligands, poly(2-cinnamoyloxyethyl methacrylate). The polymer backbone contains a cinnamoyl group that has been widely employed as a photo-cross-linker under 365 nm UV irradiation. Also, the terminal group is readily adjustable

We introduce an innovative and robust method for the preparation of nanocomposite multilayers, which allows accurate control over the placement of functional groups as well as the composition and dimensions of individual layers/internal structure. By employing the photocross-linkable polystyrene (PS-N(3), M(n) = 28.0 kg/mol) with 10 wt % azide groups (-N(3)) for host polymer and/or the PS-N(3)-SH (M(n) = 6.5 kg/mol) with azide and thiol (-SH) groups for capping ligands of inorganic nanoparticles

We introduce a novel and facile approach to improve the desalination performance of pressure-driven layer-by-layer (LbL) assembled membranes. Electrostatic LbL multilayers composed of weak polyelectrolytes (PEs), e.g., cationic poly(allylamine hydrochloride) (PAH) and anionic poly(acrylic acid) (PAA), were prepared on commercial polysulfone substrates. In order to measure the ion rejection and permeate flux of these membranes, the ionic concentration of the feed solution and operating pressure w

ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTFacile Synthesis of Thermally Stable Core−Shell Gold Nanoparticles via Photo-Cross-Linkable Polymeric LigandsMisang Yoo†, Seyong Kim†, Jongmin Lim‡, Edward J. Kramer§, Craig J. Hawker§, Bumjoon J. Kim*‡, and Joona Bang*†View Author Information† Department of Chemical and Biological Engineering, Korea University, Seoul 136-701, Republic of Korea‡ Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, Daejeo

The temperature dependence of the micelle structures formed by poly(styrene-b-isoprene) (SI) diblock copolymers in the selective solvents diethyl phthalate (DEP) and tetradecane (C14), which are selective for the PS and PI blocks, respectively, have been investigated by small angle neutron scattering (SANS). Two nearly symmetric SI diblock copolymers, one with a perdeuterated PS block and the other with a perdeuterated PI block, were examined in both DEP and C14. The SANS scattering length densi

Quantum dot (QD)-based displays call for nondestructive, high-throughput, and high-resolution patterning techniques with micrometer precision. In particular, self-emissive QD-based displays demand fine patterns of conductive QD films with uniform thickness at the nanometer scale. To meet these requirements, we functionalized QDs with photopatternable and semiconducting poly(vinyltriphenylamine-<i>random</i>-azidostyrene) (PTPA-N₃-SH) ligands in which hole-transporting triphenylamine a