| Project/Area Number |
14205133
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
高分子構造・物性(含繊維)
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| Research Institution | Hokkaido University |
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Principal Investigator |
GONG Jian Ping Hokkaido University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (20250417)
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| Co-Investigator(Kenkyū-buntansha) |
OSADA Yoshihito Hokkaido University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (60007804)
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| Project Period (FY) |
2002 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥54,080,000 (Direct Cost: ¥41,600,000、Indirect Cost: ¥12,480,000)
Fiscal Year 2005: ¥12,740,000 (Direct Cost: ¥9,800,000、Indirect Cost: ¥2,940,000)
Fiscal Year 2004: ¥12,740,000 (Direct Cost: ¥9,800,000、Indirect Cost: ¥2,940,000)
Fiscal Year 2003: ¥12,740,000 (Direct Cost: ¥9,800,000、Indirect Cost: ¥2,940,000)
Fiscal Year 2002: ¥15,860,000 (Direct Cost: ¥12,200,000、Indirect Cost: ¥3,660,000)
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| Keywords | gel / surface friction / static friction / artificial cartilage / relaxation / release / viscoelasticity / adsorption / electrostatic repulsion |
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| Research Abstract |
Our study shows that hydrogel shows a low surface sliding friction. Especially the presence of polyelectrolyte brushes on a hydrogel surface can effectively reduce the surface sliding frictional coefficient to a value as low as 10^<-4>.
The low friction of gel should have enabled the gel to find a wide application in many fields where low friction is required, such as articular cartilage, semi lunar cartilage. However, conventional hydrogels, especially polyelectrolyte gels, are mechanically too weak to be practically used in any stress or strain bearing applications. A hydrogel usually breaks down under a compressive stress not higher than 0.1 MPa. However, an articular cartilage, especially those of kneels and hips, sustains a daily compression of several to decades MPa, exhibits a friction coefficient as low as 10^<-3> over a wide range of sliding velocity. The mechanical weakness has hindered not only the extensive application of hydrogels as an industrial and biomedical materials, but also the fundamental researches on the friction behavior of gel under a pressure higher than MPa where desolvation might occur.
We discovered a general method to obtain very strong hydrogels containing 60-90 % water by inducing a double-network (DN) structure for various combinations of hydrophilic polymers. The DN hydrogel can exhibit fracture strength as high as a few to several tens of megapascals, that is, 100 kg/cm^2).
Based on these researches, we further developed a novel material, a high strength DN gel containing either a weakly cross-linked 3^<rd> network or non-cross-linked 3^<rd> linear chains which shows a fracture strength as high as 9 MPa and frictional coefficient μ as low as 10^<-4>.
The gel with both a high strength and an extremely low surface friction would find wide applications not only in industry but also in biomedical field, for example, as substitutes of articular cartilage or other bio-tissues.
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