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제  목 : Soft Matter at Rubbing Interfaces: Lessons from Nature to Design Water-friendly Tribosystems

연  사 : 이승환 교수님(Technical University of Denmark)

일  시 : 2017년 3월 30일(목) 오후 4시 30분

장  소 : 화학관 2층 서병인강의실 (330226호실)

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Soft Matter at Rubbing Interfaces: Lessons from Nature to Design Water-friendly Tribosystems

Seunghwan Lee

Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark

Life-long maintenance of biotribosystems, such as synovial joints, ocular tracts, and oral cavity, is remarkable and even puzzling considering that the base stock for the lubrication is water. For most man-made engineering systems, water is generally excluded as lubricant due to its poor capabilities to withstand external loads on its own. Nature solves this problem by incorporating pressure-responsive, “smart coatings”, such as mucus gel layers on the surface, and thus facilitate the entrainment and retainment of water (lubricant) at the rubbing interfaces. Mucins, a family of high-molecular-weight glycoproteins and a main macromolecular constituent of mucus gels, are interesting also because they show unique slipperiness at the interface composed of synthetic materials too. This, in turn, has inspired the development of mucin-like, brush-forming synthetic polymers, which can be applied in the lubrication of engineering materials with water. Biophysical properties of both mucinous glycoproteins and their mimics, brush-forming polymers, are very sensitive to environmental changes, and this feature can be exploited to optimize their properties for particular applications. Studies on soft matter at the rubbing interfaces firstly help understand the biological mechanisms of lubrication and provide useful hints for biomimetic lubrication engineering. Furthermore, various fundamental properties of soft matter on surface can be revealed only by being exposed to interfacial shear stresses. This talk will provide an overview on recent researches on the conformation, surface adsorption, and biotriobological properties of mucins/mucus gels with varying origin, purity, and environment as well as synthetic brush-like polymer chains, including poly(ethylene oxide)(PEO)-based copolymers, carbohydrate-based copolymers, and polyeletrolyte-based copolymers.