| Abstract: | Aqueous foaming solutions of permethylsiloxane surfactants and fluorocarbon surfactants are very resistant to antifoaming. Newly developed polysiloxane fluids having highly fluorinated chains showed very low surface tensions and were examined as antifoaming compounds to test against these two classes of surfactant systems. The fluorinated polysiloxanes evaluated were poly-(3,3,4,4,5,5,6,6,6 - nonafluorohexyl)methylsiloxane] (PNFHMS), and 1H,1H,2H,2H-perfluorodecyl-terminated polydimethylsiloxane (Def-DMS). Poly(dimethylsiloxane) (PDMS) was also studied as a standard siloxane polymer fluid for comparison. The antifoams composed of PNFHMS and Def-DMS polymer fluids incorporated with silica showed effective antifoaming against the low surface tension aqueous solutions of representative permethylsiloxane and fluorocarbon surfactants. |
