Surface tension of liquid polysiloxanes having fluorinated alkyl side‐chains

The surface tension of viscous polymer liquids, viz. polysiloxanes having fluorinated alkyl sidechains, was evaluated based on the pendant‐drop method. The polysiloxane fluids studied are poly‐(3,3,3‐trifluoropropylmethylsiloxane), poly(3,3,4,4,5,5,6,6,6‐nonafluorohexylmethylsiloxane) (PNFHMS), poly(3,3,4,4,5,5,6,6,7,7,8,8‐tridecafluorooctylmethylsiloxane) (PTDFOMS) and poly(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10‐heptadecafluorodecylmethylsiloxane) (PHDFDMS). The surface tension of liquid poly(dimethylsiloxane)s was also examined as standard silicone fluids. The surface tensions of liquid PNFHMS, PTDFOMS and PHDFDMS were very low, as low as the value previously reported for poly(oxyhexafluoropropylene) fluids. Low‐ and hightemperature properties of these highly fluorinated polysiloxanes were also evaluated.