8-12 Dec 2019, Singapore
2018-Now Namgo Chaired Professor (POSTECH)
2011-2014 POSTECH Fellow
2012-2015 Outside member, Board of Director of LG Chem. Co.
2009 APS fellow
2007 KAIST Alumni Award
2006 Samsung Polymer Award
2003 Scientist of Month
2004-Present: Director of the Center for Smart Block Copolymer Self-Assembly funded by the National Research Foundation in Korea
1993-Present: Assistant, Associate, and full Professor, Pohang University of Science and Technology (POSTECH) in Chemical Engineering
1991-93 Senior Research Scientist, LG Chem. Co, Korea
1990: Ph. D. from Polytechnic University in Chemical Engineering, New York, USA
1982 M. S. from KAIST (Korea Advanced Institute of Science and Technology) in Chemical Engineering, Daejeon, Korea
1980: B.S. from Seoul National University in Chemical Engineering, Seoul, Korea
Phase behavior and phase transition of block copolymers, development of new functional nanomaterials for membranes, and nanocomposites containing polymer blends and organoclays.
"Functional Nanomaterials Based on Block Copolymer Self-Assembly"
Because the microdomains obtained by block copolymer (BCP) self-assembly are mainly decided by the volume fraction of one block, it is very difficult to fabricate highly asymmetric line patterns based on BCP. We obtained highly asymmetric lamellar morphologies by the use of binary blends of block copolymers [polystyrene-b-poly(2-vinyl pyridine) copolymer (PS-b-P2VP) and PS-b-poly(4-hydroxystyrene) copolymer (PS-b-PHS)] where P2VP and PHS are capable of the hydrogen bonding. We obtained the asymmetric lamellar microdomains having lamellar width ratio of 4:1.1 This ratio was even increased up to 6:1 with increasing the degree of hydrogen bonding. Also, we observed for the first time the cylindrical and double gyroid microdomains in neat linear block copolymers at the symmetric overall volume fraction by using tetrablock copolymers PS-block-polyisoprene-block-PS-block-polyisoprene (S1I1S2I2).2
Also, nanopatterns with multiple shapes and sizes could not easily prepared by BCP self-assembly. Though various methods have been introduced in the literature to achieve dual nanopatterns for the next-generation nanolithography, all the methods are not useful for making dual-nanopatterns in a large size due to the complicated processes. By synthesizing a novel miktoarm block copolymer capable of cleavage of one block by ultraviolet, we successfully fabricated dual nanopatterns consisting of dots and lines at desired regions on a single substrate.3
A novel self-neutralization concept is introduced by using star-shaped 18 arm poly(methyl methacrylate)-block-PS copolymers ((PMMA-b-PS)18) exhibiting lamellar and PMMA cylindrical nanodomains. When a thin film was spin-coated on a substrate, vertically aligned lamellar and cylindrical nanodomains were obtained without any pre- or post-treatment, although thermal annealing for a short time (less than 30 min) was required to improve the spatial array of vertically aligned nanodomains. Moreover, vertical orientations are observed on versatile substrates, for instance, semiconductor (Si, SiOx), metal (Au), PS or PMMA-brushed substrate, and a flexible polymer sheet of polyethylene naphthalate (PEN).4
Finally, we fabricated a high-density array of “accordion-like” plasmonic silver nanorods over a large area (~cm2) exhibiting multiple electromagnetic responses in visible and near-infrared (NIR) wavelengths.5 The concept of fabricating sophisticated nanoscale architectures by utilizing block copolymer self-assembly and incorporating plasmonic metals into one nanodomains could be applied to realize large-scale metamaterials working at visible and NIR wavelengths.
1. Han, S. H.; Pryamitsyn, V.; Bae, D. S.; Kwak, J. H.; Ganesan, V.; Kim, J. K. ACS Nano 2012, 6, 7966.
2. Ahn, S.; Kim, J. K.; Zhao, G.; Duan, C.; W. Li, Macromolecules 2018, 51, 4415.
3. Choi, C.; Park, J.; Joseph, K.L. V.; Lee, L; Ahn, S.; Kwak, J.; Lee, K. S.; Kim, J. K., Nature Commun. 2017, 8, 1765.
4. Jang, S.; Lee, K.; Moon, H.C.; Kwak, K.; Park, J.; Jeon, G.; Lee, W. B.; Kim, J. K. Adv. Funct. Mater. 2015, 25, 5414.
5. Kim, M., Mun, J., Bae, S. Jeon, G., Go, M.C., Rho, J., Kim, J. K., NPG Asia Mater. 2018, 10, 190.