Surface tension of pentafluoroethane and 1,1,1,2,3,3,3-heptafluoropropane

The surface tension of pentafluoroethane (HFC-125) and 1,1,1,2,3,3,3-heptaf luoropropane (HFC-227ea) has been measured in the present work. The measure ments were conducted at vapor-liquid equilibrium conditions. Thirty-nine da ta points have been obtained by the differential capillary rise method (DCR M) in the temperature range from 243 to 340 K for HFC-227ea, and 20 data po ints from 248 to 323 K for HFC-125. The temperature uncertainty is within /-20 mK. The accuracy of surface tension measurements is estimated to be wi thin +/-0.15 mN m(-1). Also correlations of the surface tension data are pr oposed. (C) 2000 Elsevier Science B.V. All rights reserved.