Reaction of fluorinated aliphatic alcohols with calcium chloride: formation of the fluorinated alcohol/calcium fluoride nanocomposites—thermal stability and application to the surface modification of these nanocomposites

A variety of fluorinated aliphatic alcohols such as 1H,1H,2H,2H-nonafluoro-1-hexanol (FA-4), 1H,1H,2H,2H-tridecafluoro-1-n-octanol (FA-6), 1H,1H,2H,2H-heptadecafluoro-1-decanol (FA-8), 1H,1H,2H,2H,6H,6H-nonadecafluoro-1-undecanol (DTFA), 2,3,3,3-tetrafluoro-2-[1,1,2,3,3,3-hexafluoro-2-(heptafluoropropoxy) propoxy]-1-propanol (PO-3-OH), and 2,4,4,5,7,7,8,10,10,11,13,13,14,16,16,17,17,18,18,18-icosafluoro-2,5,8,11,14-pentakis(trifluoromethyl)-3,6,9,12,15-pentaoxaoctadecane-1-ol (PO-6-OH) were applied to the reaction with calcium chloride under alkaline conditions. In these fluorinated alcohols, only the DTFA can react with calcium chloride under alkaline conditions to provide the corresponding fluorinated alcohol/calcium fluoride nanocomposites. This reactivity is due to the relatively higher acidity of the inside methylene unit in the DTFA, whose acidic protons should react with the neighboring fluorines and successively with calcium chloride under alkaline conditions to afford the DTFA/calcium fluoride nanocomposites. Interestingly, the DTFA/CaF₂ nanocomposites were found to exhibit a no weight loss characteristic even after calcination at 800°C. More interestingly, the DTFA/CaF₂ nanocomposites after calcination at 800°C are applicable to the surface modification of poly(methyl methacrylate) (PMMA) to exhibit both good oleophobicity and lower refractive indices imparted by longer fluoroalkyl units in the composites on the modified PMMA film surfaces, as well as those before calcination of the DTFA/CaF₂ nanocomposites.