# Dong Ki Yoon
**Dong Ki Yoon** (윤동기) is a South Korean chemist who works on liquid crystals and self-assembly in soft matter, and is known for turning self-assembled liquid-crystal textures into lithographic templates and security devices. He is an Endowed Chair Professor in the Department of Chemistry at the [Korea Advanced Institute of Science and Technology](https://www.edgepedia.org/korea-advanced-institute-of-science-and-technology) (KAIST), where he leads the Soft Material Assembly Group.[1](https://chem.kaist.ac.kr/eng/faculty/view/id/25) • [2](https://yoon.kaist.ac.kr/members-1) He also holds adjunct professorships in the Graduate School of Nanoscience and Technology and the KAIST Institute for the NanoCentury.[2](https://yoon.kaist.ac.kr/members-1) His ORCID identifier is 0000-0002-9383-8958.[3](https://orcid.org/0000-0002-9383-8958)
| Fact | Detail |
|---|---|
| Field | Liquid crystals and self-assembly in soft matter; organic optics and electronics[1](https://chem.kaist.ac.kr/eng/faculty/view/id/25) |
| Position | Endowed Chair Professor, Department of Chemistry, KAIST; professor since September 2021[1](https://chem.kaist.ac.kr/eng/faculty/view/id/25) • [2](https://yoon.kaist.ac.kr/members-1) |
| Training | B.S. Yonsei University (2001); M.S. (2003) and Ph.D. (2007) in Chemical & Biomolecular Engineering, KAIST[4](https://pure.kaist.ac.kr/en/persons/dong-ki-yoon/) |
| Industry | Senior Engineer, Advanced Process Development Team, Memory Division, Samsung Electronics, 2007–2009[4](https://pure.kaist.ac.kr/en/persons/dong-ki-yoon/) |
| Postdoctoral work | Research Associate, Department of Physics and the Liquid Crystal Materials Research Center, University of Colorado Boulder, 2009–2011[2](https://yoon.kaist.ac.kr/members-1) |
| Signature work | "Internal structure visualization and lithographic use of periodic toroidal holes in liquid crystals", Nature Materials, 2007[5](https://www.personal.kent.edu/~olavrent/pdf/96_Internal_Structure_Visualization_and_Lithoghraphic_Nature_Materials_2007.pdf) |
| Patent | Korean application 10-2016-0033332 on lyotropic chromonic liquid-crystal coating layers for multi-domain alignment[6](https://yoon.kaist.ac.kr/publications-patents) |
## Education and career
Yoon studied chemical engineering at [Yonsei University](https://www.edgepedia.org/yonsei-university) from March 1997 to February 2001, then moved to KAIST for graduate work in Chemical & Biomolecular Engineering, completing an M.S. in February 2003 and a Ph.D. in February 2007.[1](https://chem.kaist.ac.kr/eng/faculty/view/id/25) • [4](https://pure.kaist.ac.kr/en/persons/dong-ki-yoon/) From March 2007 to March 2009 he worked as a Senior Engineer in the Advanced Process Development Team of Samsung Electronics' Memory Division, Semiconductor Business.[4](https://pure.kaist.ac.kr/en/persons/dong-ki-yoon/)
His postdoctoral position, from March 2009 to March 2011, was at the [University of Colorado Boulder](https://www.edgepedia.org/university-of-colorado-boulder), in the Department of Physics and the Liquid Crystal Materials Research Center (LCMRC).[2](https://yoon.kaist.ac.kr/members-1) He joined KAIST as an Assistant Professor in April 2011, became Associate Professor in April 2014, and has been Professor since September 2021.[1](https://chem.kaist.ac.kr/eng/faculty/view/id/25)
## Field and research program
His group's work sits at the junction of chemistry, materials science, and nanoscience, listed on the KAIST faculty page under the areas ORG, MAT, and NANO.[1](https://chem.kaist.ac.kr/eng/faculty/view/id/25) Three directions recur across his record: synthesis of soft materials including liquid crystals, supramolecules, polymers, biopolymers, and inorganic particles; nano- and microfabrication and orientation control of soft materials by topographic confinement; and organic optics and electronics built from soft materials.[1](https://chem.kaist.ac.kr/eng/faculty/view/id/25) • [4](https://pure.kaist.ac.kr/en/persons/dong-ki-yoon/)
## Representative work
His 2007 paper in *Nature Materials* showed that perfect ordered arrays of toric focal conic domains (TFCDs) covering large areas could be formed from semi-fluorinated [smectic liquid crystals](https://www.edgepedia.org/smectic-liquid-crystal) grown in silicon microchannels.[5](https://www.personal.kent.edu/~olavrent/pdf/96_Internal_Structure_Visualization_and_Lithoghraphic_Nature_Materials_2007.pdf) The TFCDs were arranged in periodically ordered arrays with an average center-to-center spacing of about 2.5 µm, and each TFCD was associated with a depression of the smectic A free surface by a depth of about 300 nm.[5](https://www.personal.kent.edu/~olavrent/pdf/96_Internal_Structure_Visualization_and_Lithoghraphic_Nature_Materials_2007.pdf) The paper introduced "smectic liquid-crystal lithography": TFCDs grown from a mixture of liquid-crystal molecules and fluorescent particles acted as a template, trapping the particles in an ordered array.[5](https://www.personal.kent.edu/~olavrent/pdf/96_Internal_Structure_Visualization_and_Lithoghraphic_Nature_Materials_2007.pdf)
A 2010 follow-up in the *Journal of Materials Chemistry* developed highly periodic patterns with sub-micrometer features over large areas, using hexagonal TFCD arrays as molds for UV-curable polymers to make liquid-crystal defect stamps, with patterns transferred by microcontact printing; the paper argued that smectic liquid crystals are strong candidates for periodic templates compared with other soft building blocks such as block copolymers, colloids, and surfactants.[7](https://doi.org/10.1039/b924401h)
Recent work carries the defect-as-pattern idea into security. In 2023 his group published "Paintable Physical Unclonable Function Using DNA" and "Planar spin glass with topologically-protected mazes in the liquid crystal targeting for reconfigurable micro security media", both in *Advanced Materials*.[1](https://chem.kaist.ac.kr/eng/faculty/view/id/25) In 2025 several further *Advanced Materials* papers extended the program: one on spatial control of chiral self-assembly in liquid-crystal polymer networks, and one on a reconfigurable liquid-crystal physical unclonable function.[8](https://koasas.kaist.ac.kr/handle/10203/334950) • [9](https://koasas.kaist.ac.kr/handle/10203/334879)
## Applications: lithography, anti-counterfeiting and patents
A 2022 chiral PUF built from racemized photonic crystals, arising from spontaneous mirror-symmetry breaking in molecular self-assembly, had an encoding capacity of about \(10^{13{,}000}\) in an area of 1 mm², a level the KAIST release estimated would take about \(10^{199}\) years to predict by a typical brute-force algorithm; random patterns removed by heating could not be intentionally recovered even by the manufacturer of the same sample, and the patterns could be read with cell phones.[10](https://kmatrix.kaist.ac.kr/racemized-photonic-crystals-for-physical-unclonable-function/)
The 2025 *Advanced Materials* PUF went further by integrating the function into an [organic field-effect transistor](https://www.edgepedia.org/organic-field-effect-transistor), combining optical fingerprint textures with the random molecular alignment of a semiconductive smectic liquid crystal, so that optical and electrical PUFs coexist in one device.[9](https://koasas.kaist.ac.kr/handle/10203/334879) The key can be reconfigured by a simple heating and cooling process, overcoming the fixed-key limitation of earlier PUFs, and the system supports hierarchical authentication for anticounterfeiting and cryptographic applications.[9](https://koasas.kaist.ac.kr/handle/10203/334879)
On the lithography side, a 2016 Korean patent application (10-2016-0033332) covers a method of preparing coating layers of lyotropic chromonic liquid crystal for multi-domain liquid-crystal alignment.[6](https://yoon.kaist.ac.kr/publications-patents)
## Recent work
His 2023 publications also include a *Nature Communications* paper on plasmonic metasurfaces of cellulose nanocrystal matrices with aligned gold nanorods for photothermal anti-icing (volume 14, article 8096, December 2023), and an *ACS Nano* paper on on-demand aligned DNA hydrogels via light scanning (volume 17, pages 22778–22787, November 2023).[1](https://chem.kaist.ac.kr/eng/faculty/view/id/25) The 2025 record shows the group's direction toward reconfigurable security media and tunable chiral soft materials, with the two 2025 papers on chiral self-assembly and reconfigurable PUFs.[8](https://koasas.kaist.ac.kr/handle/10203/334950) • [9](https://koasas.kaist.ac.kr/handle/10203/334879) In the 2025 chiral self-assembly work, spontaneous twist self-assembly generates periodic zigzag line defects that define alternating enantiomeric domains; an LC polymer network stabilizes the defects, and their kink density and orientation can be modulated by sample thickness, applied voltage, and electrode configurations, giving tunable periodicity and macroscopic direction.[8](https://koasas.kaist.ac.kr/handle/10203/334950)
## References
1. [Faculty profile: Professor Yoon, Dong Ki, KAIST Department of Chemistry](https://chem.kaist.ac.kr/eng/faculty/view/id/25)
2. [Members, Soft Material Assembly Group @ KAIST](https://yoon.kaist.ac.kr/members-1)
3. [Dong Ki Yoon (0000-0002-9383-8958), ORCID](https://orcid.org/0000-0002-9383-8958)
4. [Dong Ki Yoon, KAIST Pure research portal](https://pure.kaist.ac.kr/en/persons/dong-ki-yoon/)
5. [Internal structure visualization and lithographic use of periodic toroidal holes in liquid crystals, Nature Materials (2007)](https://www.personal.kent.edu/~olavrent/pdf/96_Internal_Structure_Visualization_and_Lithoghraphic_Nature_Materials_2007.pdf)
6. [Publications and patents, Soft Material Assembly Group @ KAIST](https://yoon.kaist.ac.kr/publications-patents)
7. [Self-assembled periodic liquid crystal defects array for soft lithographic template, Journal of Materials Chemistry (2010)](https://doi.org/10.1039/b924401h)
8. [Spatial Control of Chiral Self-Assembly and Lithographic Applications in Liquid Crystal Polymer Network, KOASAS record](https://koasas.kaist.ac.kr/handle/10203/334950)
9. [Reconfigurable Liquid Crystal-Based Physical Unclonable Function Integrating Optical and Electrical Responses, KOASAS record](https://koasas.kaist.ac.kr/handle/10203/334879)
10. [Racemized photonic crystals for physical unclonable function, KAIST MatriX](https://kmatrix.kaist.ac.kr/racemized-photonic-crystals-for-physical-unclonable-function/)
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*Topic: Encyclopedia › Physical world and mathematics › Physical and mathematical scientists › Physicists and astronomers › Researchers in soft matter, statistical physics, and biological physics › Liquid crystals and self-assembly*
*Initially written Sep 21, 2026 · Reviewed: Sep 25, 2026 · Edited: Sep 25, 2026; Oct 15, 2026 · Last review: Sep 25, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license