Thin coating manufactured by vapor deposition of solid oligomers

Abstract

A monomer is selected to produce a polymeric film having desirable characteristics for a particular application. The monomer is polymerized under controlled conditions to produce a solid oligomer having those characteristics at a molecular weight suitable for evaporation under vacuum at a temperature lower than its thermal decomposition temperature. The process of polymerization to produce the oligomer is carried out under conditions that yield a finite molecular-chain length with no residual reactive groups. The solid oligomer so produced is liquefied and extruded as a film onto a revolving drum in the evaporation section of a conventional vapor deposition chamber, and it is then cryocondensed on a cold substrate to form a solid thin film having the same desirable characteristic selected in the solid oligomer constituting the starting material. As a result of the initial complete reaction to produce the oligomer, the thin-film product does not contain unreacted groups and all attendant disadvantages are avoided.