Education & Certifications

  • M.S., Stanford University, Chemical Engineering (2018)
  • B.S., Seoul National University, Chemical and Biological Engineering (2015)

Stanford Advisors

All Publications

  • An Intrinsically Stretchable High-Performance Polymer Semiconductor with Low Crystallinity ADVANCED FUNCTIONAL MATERIALS Zheng, Y., Wang, G., Kang, J., Nikolka, M., Wu, H., Tran, H., Zhang, S., Yan, H., Chen, H., Yuen, P., Mun, J., Dauskardt, R. H., McCulloch, I., Tok, J., Gu, X., Bao, Z. 2019
  • An Ultrastretchable and Self-Healable Nanocomposite Conductor Enabled by Autonomously Percolative Electrical Pathways ACS NANO Kim, S., Seo, H., Kang, J., Hong, J., Seong, D., Kim, H., Kim, J., Mun, J., Youn, I., Kim, J., Kim, Y., Seok, H., Lee, C., Tok, J., Bao, Z., Son, D. 2019; 13 (6): 6531–39
  • Polyimide-PEG Segmented Block Copolymer Membranes with High Proton Conductivity by Improving Bicontinuous Nanostructure of Ionic Liquid-Doped Films MACROMOLECULAR CHEMISTRY AND PHYSICS Woo, E., Coletta, E., Holm, A., Mun, J., Toney, M. F., Yoon, D. Y., Frank, C. W. 2019; 220 (9)
  • Modular and Reconfigurable Stretchable Electronic Systems ADVANCED MATERIALS TECHNOLOGIES Kang, J., Son, D., Vardoulis, O., Mun, J., Matsuhisa, N., Kim, Y., Kim, J., Tok, J., Bao, Z. 2019; 4 (3)
  • Conjugated Carbon Cyclic Nanorings as Additives for Intrinsically Stretchable Semiconducting Polymers. Advanced materials (Deerfield Beach, Fla.) Mun, J., Kang, J., Zheng, Y., Luo, S., Wu, H. C., Matsuhisa, N., Xu, J., Wang, G. N., Yun, Y., Xue, G., Tok, J. B., Bao, Z. 2019: e1903912


    Molecular additives are often used to enhance dynamic motion of polymeric chains, which subsequently alter the functional and physical properties of polymers. However, controlling the chain dynamics of semiconducting polymer thin films and understanding the fundamental mechanisms of such changes is a new area of research. Here, cycloparaphenylenes (CPPs) are used as conjugated molecular additives to tune the dynamic behaviors of diketopyrrolopyrrole-based (DPP-based) semiconducting polymers. It is observed that the addition of CPPs results in significant improvement in the stretchability of the DPP-based polymers without adversely affecting their mobility, which arises from the enhanced polymer dynamic motion and reduced long-range crystalline order. The polymer films retain their fiber-like morphology and short-range ordered aggregates, which leads to high mobility. Fully stretchable transistors are subsequently fabricated using CPP/semiconductor composites as active layers. These composites are observed to maintain high mobilities when strained and after repeated applied strains. Interestingly, CPPs are also observed to improve the contact resistance and charge transport of the fully stretchable transistors. ln summary, these results collectively indicate that controlling the dynamic motion of polymer semiconductors is proved to be an effective way to improve their stretchability.

    View details for DOI 10.1002/adma.201903912

    View details for PubMedID 31489716

  • Electronic Skin: Recent Progress and Future Prospects for Skin-Attachable Devices for Health Monitoring, Robotics, and Prosthetics. Advanced materials (Deerfield Beach, Fla.) Yang, J. C., Mun, J., Kwon, S. Y., Park, S., Bao, Z., Park, S. 2019: e1904765


    Recent progress in electronic skin or e-skin research is broadly reviewed, focusing on technologies needed in three main applications: skin-attachable electronics, robotics, and prosthetics. First, since e-skin will be exposed to prolonged stresses of various kinds and needs to be conformally adhered to irregularly shaped surfaces, materials with intrinsic stretchability and self-healing properties are of great importance. Second, tactile sensing capability such as the detection of pressure, strain, slip, force vector, and temperature are important for health monitoring in skin attachable devices, and to enable object manipulation and detection of surrounding environment for robotics and prosthetics. For skin attachable devices, chemical and electrophysiological sensing and wireless signal communication are of high significance to fully gauge the state of health of users and to ensure user comfort. For robotics and prosthetics, large-area integration on 3D surfaces in a facile and scalable manner is critical. Furthermore, new signal processing strategies using neuromorphic devices are needed to efficiently process tactile information in a parallel and low power manner. For prosthetics, neural interfacing electrodes are of high importance. These topics are discussed, focusing on progress, current challenges, and future prospects.

    View details for DOI 10.1002/adma.201904765

    View details for PubMedID 31538370

  • An integrated self-healable electronic skin system fabricated via dynamic reconstruction of a nanostructured conducting network NATURE NANOTECHNOLOGY Son, D., Kang, J., Vardoulis, O., Kim, Y., Matsuhisa, N., Oh, J., To, J. F., Mun, J., Katsumata, T., Liu, Y., McGuire, A. F., Krason, M., Molina-Lopez, F., Ham, J., Kraft, U., Lee, Y., Yun, Y., Tok, J., Bao, Z. 2018; 13 (11): 1057-+
  • Effect of Nonconjugated Spacers on Mechanical Properties of Semiconducting Polymers for Stretchable Transistors ADVANCED FUNCTIONAL MATERIALS Mun, J., Wang, G., Oh, J., Katsumata, T., Lee, F. L., Kang, J., Wu, H., Lissel, F., Rondeau-Gagne, S., Tok, J., Bao, Z. 2018; 28 (43)
  • Nonhalogenated Solvent Processable and Printable High-Performance Polymer Semiconductor Enabled by Isomeric Nonconjugated Flexible Linkers MACROMOLECULES Wang, G., Molina-Lopez, F., Zhang, H., Xu, J., Wu, H., Lopez, J., Shaw, L., Mun, J., Zhang, Q., Wang, S., Ehrlich, A., Bao, Z. 2018; 51 (13): 4976–85
  • Tough and Water-Insensitive Self-Healing Elastomer for Robust Electronic Skin ADVANCED MATERIALS Kang, J., Son, D., Wang, G., Liu, Y., Lopez, J., Kim, Y., Oh, J., Katsumata, T., Mun, J., Lee, Y., Jin, L., Tok, J., Bao, Z. 2018; 30 (13): e1706846


    An electronic (e-) skin is expected to experience significant wear and tear over time. Therefore, self-healing stretchable materials that are simultaneously soft and with high fracture energy, that is high tolerance of damage or small cracks without propagating, are essential requirements for the realization of robust e-skin. However, previously reported elastomers and especially self-healing polymers are mostly viscoelastic and lack high mechanical toughness. Here, a new class of polymeric material crosslinked through rationally designed multistrength hydrogen bonding interactions is reported. The resultant supramolecular network in polymer film realizes exceptional mechanical properties such as notch-insensitive high stretchability (1200%), high toughness of 12 000 J m-2 , and autonomous self-healing even in artificial sweat. The tough self-healing materials enable the wafer-scale fabrication of robust and stretchable self-healing e-skin devices, which will provide new directions for future soft robotics and skin prosthetics.

    View details for PubMedID 29424026

  • Taming Charge Transport in Semiconducting Polymers with Branched Alkyl Side Chains ADVANCED FUNCTIONAL MATERIALS Schroeder, B. C., Kurosawa, T., Fu, T., Chiu, Y., Mun, J., Wang, G., Gu, X., Shaw, L., Kneller, J. E., Kreouzis, T., Toney, M. F., Bao, Z. 2017; 27 (34)
  • Phase transition of block copolymer/homopolymer binary blends under 2D confinement MACROMOLECULAR RESEARCH Kim, Y., Mun, J., Yu, G., Char, K. 2017; 25 (6): 656–61