Journal of Colloid and Interface Science, Vol.428, 276-285, 2014
Effects of chemical structure on the dynamic and static surface tensions of short-chain, multi-arm nonionic fluorosurfactants
Fluorinated surfactants with short perfluoroalkyl chains (R-F) as potential substitutes for the environmentally questionable, long R-F systems are presented. Three types of nonionic hydrophilic-fluorophilic amphiphiles are synthesized and evaluated based on surface activity in equilibrated (static) and non-equilibrated (dynamic) states. Furthermore, several mono- and disaccharide-based fluorosurfactants are also examined as potential non-bioaccumulative alternatives. A correlation between the chemical structure and resulting surface properties is made by comparing R-F length, number and size, alkyl-spacer, and hydrophilic moieties. Based on dynamic and static surface tension experiments, the effects of surfactant structure are summarized to provide a basis for the future design of fluorosurfactants. We have found that surfactants with more perfluorinated chains tend to have a higher surface tension reduction, but typically result in slower dynamic behaviors. Using the presented structural characteristics, surfactants with R-F < 4 can be prepared with static surface tensions as low as 18.1 mN/m or reduce surface tension within milliseconds. (C) 2014 Published by Elsevier Inc.
Keywords:Fluorosurfactants;Static surface tension;Dynamic surface tension;Multi-arm structures;Structure-property relations;Non-ionic surfactants;Short perfluoroallcyl chains