Theory of a Possible Mechanism for Lubrication and Surface Protection by an Electrically Neutral Hydrogels

It is demonstrated that polymers sticking out of the surface of a neutral hydrogel are capable of preventing adhesive forces from pulling a hydrogel into close contact with a surface against which it is pressed. The proposed mechanism for lubrication or surface protection suggests a possible mechanism for protecting the cornea from a contact lens, which is held against the eye by Laplace pressure. This mechanism, however, is only able to keep a gel coated surface from sticking to a surface against which it is pressed, if the gel and surface are bathed in fluid. Expected optical properties of the gel-surface interface are discussed, in order to suggest possible ways to study the gel-solid interface experimentally.