- 本系公告 /
Properties and structures of hydrogels controlled by coordination bond
Professor Daewon Sohn
Metal complexation–based gelation imparts load-bearing hydrogels with striking properties like reversibility, self-healing, and mechanical tunability. Using a bio-inspired metal-catechol complex, these properties have been introduced to a variety of polymer hydrogels. We developed hyaluronic acid (HA) hydrogels by regulating the gelation kinetics of Fe3+ and a catechol cross-linker, including Fe3+-induced covalent bonding and coordination bonding. Dual roles of Fe3+ in catechol-modified HA (HA-CA), Fe3+-catechol coordination, and catechol oxidation followed by a coupling reaction, were selectively applied for different gelations. Tetra-poly(ethylene glycol) with catechol end groups (4-PCA) was also crosslinked through coordination bonds between catechol moieties and Fe(III) ions, which produce bis-complex and tris-complex depending on pH levels. The structure and properties of 4-PCA gels were examined upon the bonding types controlled by pH levels and molar ratios between catechol groups and Fe(III) ions. The results show structure and properties of gels can be controlled by geometries of crosslinking units as a strategy to develop novel polymer gels.
Daewon SOHN is a professor in the Department of Chemistry at Hanyang Univ., Seoul, Korea. He received his B.S (1984) and M.S. (1986) degrees from Hanyang Univ. and his Ph.D. (1994) from the Department of Chemistry at Louisiana State Univ., USA, (supervisor: Paul Russo). He was a postdoctoral fellow at Univ. of Wisconsin (supervisor: Hyuk Yu) (1994-1996) and Univ. of Toronto (supervisor: Eugenia Kumacheva) (1996-1997) before he joined Hanyang Univ. as a faculty in 1997. He also had experience in Combinatorial Group in NIST, USA, Kyushu Univ. (in Atsushi Takahara’s) and RIKEN, Japan (in Mizuo Maeda’s), and USTC-Hufei and CUHK, China (in Chi Wu’s) as a visiting scholar. He had served as a dean of the College of Natural Sciences at Hanyang Univ. for 2016-2020 and an editor in Polymer Bulletin (Springer) since 2008. His research interests are polymer characterizations in solution (3D) and at the interface (2D) by light scattering, X-ray and neutron scattering. Recently he has been interested in polymer hydrogels and nanocomposites.