Stabilization of Fluorocarbon Emulsion by Fluorinated Nonionic Surfactants

Abstract

The stabilities of 20% fluorocarbon (FC) /water emulsions containing 5% fluorinated nonionic surfactants were determined by measuring the variation of droplet diameter distribution with time (up to 10 months). For comparison of less effective emulsifiers, the rate of phase separation was also used. O/W emulsions containing HCF2 (CF2) 3CH2O (C2H4O) 9.7H showed low stability, but those stabilized by HCF2 (CF2) 7CH2O (C2H4O) 10.5H showed excellent stability. Although emulsions containing HCF2 (CF2) 5CH2O (C2H2O) 10.3H separate a minor proportion of the aqueous phase in a relatively short time, the distribution of FC droplet diameter changed little over a long period.In the present investigation, emulsions stabilized by CF3 (CF2) 6CH2O (C2H4O) 10.3H exhibited the highest stability, indicating the importance of a greater affinity of the terminal CF3 group for FC.The percentages of the aqueous phase formed 5h after preparation of emulsions containing various surfactants were as follows : HCF2 (CF2) 7CH2O (C2H4O) 10.5H (0%), CF3 (CF2) 6CH2O (C2H4O) 10.3H (00.3%), CF3 (CF2) 5CH2O (C2H4O) 10.3H (00.6%), HCF2 (CF2) 3CH2O (C2H4O) 9.7H (01%), HCF2 (CF2) 5CH2O (C2H4O) 10.3H (12.613.4%), CH3 (CH2) 11O (C2H4O) 8H (6670%).