Abstract: An electronic or electrical device or component thereof having a coating formed thereon by exposing said electronic or electrical device or component thereof to a plasma comprising one or more monomer compounds for a sufficient period of time to allow a protective polymeric coating to form on a surface thereof; wherein the protective polymeric coating forms a physical barrier over a surface of the electronic or electrical device or component thereof; wherein each monomer is a compound of formula I(a): or a compound of formula I(b) wherein each of R1 to R9 is independently selected from hydrogen or halogen or an optionally substituted C1-C6 branched or straight chain alkyl group; each X is independently selected from hydrogen or halogen; a is from 0-6; b is from 2 to 14; and c is 0 or 1; and wherein when each X is F or when at least one X is halogen, in particular F, the FTIR/ATR intensity ratio of CX3/C?O of the coating is less than (c+1)0.6e?0.