A method for forming a polymeric coating on a substrate surface, by plasma treating a mixture comprising a free-radical initiated polymerisable monomer having one or more free-radical polymerisable groups in the presence of a free radical initiator, wherein said plasma treatment is a soft ionisation plasma process (a process wherein precursor molecules are not fragmented during the plasma process and as a consequence, the resulting polymeric coating has the physical properties of the precursor or bulk polymer) aid depositing the resulting polymeric coating material onto a substrate surface.