AbstractNovel biocompatible polymer films were derived from LLA with molecularly smooth surfaces by using a plasma deposition method significantly enhanced with higher monomer vapor densities. It was found that hydrocarbons (and chain crosslinks) increased relative to the oxygen‐containing moieties as plasma power or reaction time increased, following a reaction scenario dominated by energy‐mediated molecular scission pathways. With the hydroxyl groups being retained, the films of excellent mechanical strength were highly hydrophilic and manifested excellent biocompatibility applicable for a wide range of biomedical coatings. This work also demonstrated the feasibility of converting common molecules to useful polymers under appropriate plasma conditions.magnified image