coatings having very low critical surface tensions comprise a hydrophilic polymer such as polyacrylamide , an ionic perfluorocarbon compound such as 3 - sulfonyl ) amino ]- n , n , n - trimethyl - 1 - propanaminium iodide and a cyclic sulfonium zwitterion cross - linking agent such as 2 , 2 - bis - propylidene . such coatings are most advantageously employed as release coatings on internal surfaces of chemical reaction vessels in order to minimize the deposition of undesirable materials on such internal surfaces .