The present invention provides an electronic or electrical device or component thereof comprising a cross-linked polymeric coating on a surface of the electronic or electrical device or component thereof; wherein the cross-linked polymeric coating is obtainable by exposing the electronic or electrical device or component thereof to a plasma comprising a monomer compound and a crosslinking reagent for a period of time sufficient to allow formation of the cross-linked polymeric coating on a surface thereof,wherein the monomer compound has the following formula: where R1, R2 and R4 are each independently selected from hydrogen, optionally substituted branched or straight chain C1-C6 alkyl or halo alkyl or aryl optionally substituted by halo, and R3 is selected from: where each X is independently selected from hydrogen, a halogen, optionally substituted branched or straight chain C1-C6 alkyl, halo alkyl or aryl optionally substituted by halo; and n1 is an integer from 1 to 27; and wherein the crosslinking reagent comprises two or more unsaturated bonds attached by means of one or more linker moieties and has a boiling point at standard pressure of less than 500° C.