Facile creation of modified surface possessing the controlled wettability between superamphiphobic and superoleophobic–superhydrophilic characteristics by using perfluorocarboxamides/calcium carbonate/calcium fluoride nanocomposites: Application to the separation of oil and water

A variety of perfluoroacyl fluorides such as perfluoro-3-(1-piperidinyl)propionyl fluoride, perfluoro-2-methyl-3-morpholinopropionyl fluoride, perfluoro-3-di-n-propylaminopropionyl fluoride, and perfluoro-3-di-n-butylaminopropionyl fluoride were applied to the nanocomposite reactions with calcium carbonate nanoparticles under alkaline conditions to afford the corresponding perfluorocarboxamides/calcium carbonate/calcium fluoride nanocomposites. The modified glass surfaces treated with the fluorinated nanocomposites, which were prepared by using perfluoro-2-methyl-3-morpholinopropionyl fluoride and perfluoro-3-(1-piperidinyl)propionyl fluoride, afforded an oleophobic-superhydrophilic characteristic. The fluorinated nanocomposites, of whose each preparative feed ratio of perfluoro-3-di-n-propylaminopropionyl fluoride (or PF-DBAPF) and CaCO3 is 0.50 (g/g) (2.50 (mol/mol) ), can provide a superamphiphobic characteristic on the modified surfaces; however, the lower feed ratios: 0.25-0.17 (g/g) (1.25-0.83 (mol/mol)) of the acyl fluorides based on CaCO3 can afford a superoleophobic-superhydrophilic characteristic on the modified surfaces. The similar wettability was observed on the modified filter paper and polyethylene terephthalate fabric surfaces by using the fluorinated nanocomposites, which were prepared with perfluoro-3-di-n-butylaminopropionyl fluoride. Interestingly, these modified filter paper and polyethylene terephthalate fabric swatch were applied to the separation membranes for not only the mixture of oil and water but also the oil-in-water emulsion. The modified filter paper treated with the fluorinated nanocomposites possessing a superamphiphobic characteristic was also applied to the separation membrane for the mixture of fluorocarbon and hydrocarbon.