Protective Coatings

A coating composition comprising a first layer and a second layer disposed on top of the first layer, wherein the first layer comprises colloidal silica and a first polymer comprising monomer units represented by the structures:

• wherein R1 is alkyl, R2 is alkyl, and each R3 is independently hydrogen or an oxygen-silicon covalent bond to at least a portion of the colloidal silica;
• and
• the second layer comprises a carbon additive and a crosslinked polymer comprising a second polymer and a third polymer, wherein the second polymer comprises monomer units represented by the structures:
• wherein R4 is alkyl, R5 is alkyl, and each R6 is alkyl;
• and the third polymer comprises monomer units represented by the structures:
• wherein R7 is alkyl, R8 is alkyl, and each R9 is alkyl, wherein
• in the second polymer and
• in the third polymer represents a covalent bond therebetween.