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Joona Bang(방준하) 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.1
Bottlebrush polymers (BBPs) have been of significant interest for over two decades due to their unique physical and solution properties. With recent progress in synthetic techniques, their detailed architectures can be precisely controlled with various monomers. The most popular method to synthesize BBPs is ring-opening metathesis polymerization (ROMP) with Grubbs’ catalyst. In this case, it has been well recognized that the purity of macromonomers (MMs) is critical for a successful ROMP reaction. To provide a better guide of MM synthesis for a ROMP, we investigated the impact of various impurities on MM-ROMP by adding possible poisoning species to purified MMs. As an example of BBP application, we demonstrate that BBPs with statistical side-chains were employed as additives to induced the perpendicular orientation of high χ block copolymer lamellae in thin films through architecture-induced surface segregation.
Block Copolymer Nanolithography: Translation of Molecular Level Control to Nanoscale Patterns
Bang, Joona,Jeong, Unyong,Ryu, Du Yeol,Russell, Thomas P.,Hawker, Craig J. WILEY‐VCH Verlag 2009 Advanced Materials Vol.21 No.47
<P><B>Abstract</B></P><P>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.</P>
Design and Synthesis of Bottlebrush Copolymers as Functional Additives for Various Applications
Joona Bang(방준하) 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.2
Bottlebrush polymers (BBPs) have been of significant interest for over two decades due to their unique physical and solution properties. With recent progress in synthetic techniques, their three-dimensional architectures can be precisely controlled with various monomers. In this presentation, I will demonstrate the potential ability of BBPs as functional additives in various applications. First, BBPs with statistical sidechains were employed as additives to induce the perpendicular orientation of high χ block copolymer in thin films through architecture-induced surface segregation. As another examples, BBPs were used as functional additives for cathode in Li-ion battery or epoxy resins to improve their desired properties by taking advantage of BBP architectures and functionalities.
On the Selection of FCC and BCC Lattices in Poly(styrene-b-isoprene) Copolymer Micelles
Bang, Joona,Lodge, Timothy P. The Polymer Society of Korea 2008 Macromolecular Research Vol.16 No.1
Spherical micelles of poly(styrene-b-isoprene) (SI) diblock copolymers in selective solvents have been reported to pack onto either face-centered cubic (fcc) or body-centered cubic (bcc) lattices. The selection rule for fcc and bcc lattices has been understood in terms of the intermicellar potentials, and they have been quantified using the ratio of the corona layer thickness to the core radius, $L/R_c$, as suggested by McConnell and Gast. In order to test the validity of the McConnell-Gast criterion, this study compared the $L/R_c$ values from various solutions i.e. nine SI copolymers in several different selective solvents. The McConnell-Gast criterion was not found to be a determining factor, even though it could explain the fcc/bcc selection qualitatively. From the phase diagrams, the transition between fcc and bcc phases was also considered as a function of concentration and temperature, and their physical mechanisms are discussed based on the recent mean-field calculation reported by Grason.
Phase behaviors of a mixture of two kinds of Pluronic triblock copolymers in aqueous solution
Jang, Jong Dae,Bang, Joona,Han, Young Soo,Sokolova, Anna,Kim, Tae-Hwan Elsevier 2018 PHYSICA B-CONDENSED MATTER - Vol.551 No.-
<P><B>Abstract</B></P> <P>A new method to easily derive the phase transition of amphiphilic block copolymer in aqueous solution is suggested in this study. Using two kinds of Pluronic triblock copolymers, which have different mass fractions of the hydrophilic part of the block copolymer, the mixed block copolymers in aqueous solution self-assembled into a variety of nanostructures. Small angle neutron scattering revealed that the block copolymer complex formed spheres, cylinders, and vesicles depending on both the concentration of another Pluronic block copolymer (Pluronic PE6200) as an additive and temperature. This phase behavior can be easily explained in terms of the hydrophobicity of the block copolymer by increasing its effective hydrophobic moiety and temperature.</P>