English Abstract
Tough Gel with Low Surface Friction
Jian Ping GONG
Graduate School of Science Hokkaido University
Nippon Gomu Kyokaishi,(2005),78(4),130-134 General Review in Japanese

The author's research group have systematically studied the surface sliding friction of hydrogels, and various unique features in gel friction have been discovered. The frictional force and its dependencies on the load are quite different depending on the chemical structures of the gels, surface properties of the opposing substrates, and the measurement condition, which are completely different from those of solids. Most importantly, the friction coefficient of gels exhibits a value as low as 0.001, which cannot be obtained from the friction between two solid materials.
Therefore, gels have a high potential as a low friction material, such as an artificial cartilage. However, conventional gels are mechanically too weak to be used as load bearing materials. The author's research group recently developed a general method to obtain very strong gels by introducing a double network structure of the gel. These high strength hydrogels, containing 90 water, sustain a compressive pressure as high as decades of MPa and show a high wear resistance due to their extremely low friction. These gels might open new era of soft and wet materials for substituting articular cartilage and other tissues.

Gel,Friction,Tough,Artificial Organ