HW 5 Problem 4 The term "polymer brush" refers to the connection of polymers to a surface to act as a lubricant. The connection is referred to as "tethering". In order to be effective, the grafting of the polymer brushes must be dense and it must be immersed in a good solvent. This, in turn, will result in a low frictional surface. The advantage of a polymer brush opposed to a liquid lubricant is that the polymer brush will remain in place where as a liquid lubricant must be bounded and/or pressurized to keep it in place. This is especially useful in systems where the sliding motion between two surfaces is of a low velocity.