Reduction and Control of Friction in Hydrogels

Hydrogels are soft elastic materials composed of sparsely crosslinked polymers and a large amount of water. Corresponding to such a specific structure of hydrogels, several striking features, such as flexibility, optical transparency, water retention (swelling) ability, stimuli (pH, temperature, electric field) response, and so on, are provided. Owing to the similarities in structures and properties to living tissues, hydrogels are expected to be biocompatible materials or replacements for damaged parts of the human body, such as artificial articular skins, corneas, and cartilages.
In this mini-review, we focus on the frictional properties of hydrogels.