Bottlebrush polymer compositions, lubricating fluid, porous materials comprising said compositions, and surface bearing said compositions

A mixture of polymers with lubricating properties is provided. The polymer can be used to produce a lubricating fluid. They can also be born on a surface or embedded in a porous material. This mixture of polymers comprises (a) a pharmaceutically acceptable bottle-brush polymer comprising a back bone with polymeric pendant chains, and (b) a pharmaceutically acceptable linear polymer. In the lubricating fluid, the bottle-brush polymer and the linear polymer are dissolved together in a pharmaceutically acceptable solvent.